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Results in Journal Peruvian Journal of Agronomy: 59

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A. Cerna, D. Vecco-Giove, M. Doria, H. Panduro, J. Rojas, P. García, , B. Sangama, J. Macedo, M. Ubeda, et al.
Peruvian Journal of Agronomy, Volume 5, pp 44-59; https://doi.org/10.21704/pja.v5i2.1773

Abstract:
The consumption of insects is a widespread practice among indigenous or native peoples of the Amazon. To assess the knowledge of the diversity of resources for entomophagy from the perspective of these peoples, testimonies or references about knowledge and feeding traditions of 100 people were collected in 37 localities in seven provinces of the department of San Martín in the basin of the Huallaga River. One cumulative species curve and the probability function of new species were estimated, then the probability of not finding a new species (99.5 %) to n100 was determined. The specimens that were captured in the field (54 %) were compared with representative specimens and databases, and the information provided by the participants was analysed to approximate the preliminary taxonomic locations of the remaining part of the sample. We found 46 resources for entomophagy and reported for first time in the Peruvian Amazon, the feeding with Chrysophora chrysochlora, Podalia sp., Lusura chera, and Cymothoidae, among others. Entomophagy is a deeply rooted practice in the native and riverine populations of the Huallaga basin, where Rhynchophorus palmarum, Rhinostomus barbirostris, Atta cephalotes sspp. and Brassolis sophorae were the most consumed for 78 % – 97 % of people. The least consumed species have the common characteristic of being scarce and they were part of the diet of the oldest segment in previous decades. At least 10 resources ceased to be consumed by the members of the sample. In addition to nutritional potential, the diversity of edible arthropod fauna represents complementary values for community health and cultural identity; however, most of these resources (87 %) are threatened and could disappear in brief time, as is the knowledge related to their use.
Alejandro Kepler Llanos Melo, Walter Eduardo Apaza-Tapia
Peruvian Journal of Agronomy, Volume 5, pp 60-70; https://doi.org/10.21704/pja.v5i2.1771

Abstract:
Stem-end rot (SER) of avocado is caused by several fungal species, and it is presented worldwide. This plant disease currently affects several avocado producer regions in Peru, causing fruit rot, impacting the industry negatively. Research about SER distribution in the canopy of avocado trees is limited. Thus, the present study aimed to compare which areas in the canopy are prone to have more SER in ‘Hass’ avocado harvested fruit in two different coastal areas in Peru. The experiment was conducted in the northern (Barranca) and southern (Cañete) of Lima. ‘Hass’Avocado fruits from both producer areas were collected to identify the causal agent; Lasiodiplodia theobromae was isolated from infected fruits. Identification was conducted based on morphological features and a partial DNA sequence of the translation elongation factor 1-α gene (tef1-α). The results showed that fruits inside the tree canopy were prone to have a higher disease incidence than the fruits located in the external site (P<0.001). Besides, internal-site fruits displayed a higher percentage of infected fruit for each grade disease (P<0.001) than external-site fruits, except for grade 0 (fruits without symptoms) and grade 1. Finally, the results suggested that the altitude where the fruit is positioned on the canopy could influence the incidence of SER, where fruits located in the high part revealed less incidence than the low section. The results are valuable for enhancing management strategies and avoiding postharvest loss of avocado fruits in our region.
Suzan Abd El- Latif Kamel Ibrahim, Mohamed Ali Abdelsatar, Mohamed Abd El-Raheem Ahmed, Magdy M. Niazy
Peruvian Journal of Agronomy, Volume 5, pp 1-17; https://doi.org/10.21704/pja.v5i1.1656

Abstract:
Six divergent genotypes of sesame (Sesamum indicum L.) were crossed using a half diallel excluding reciprocal crosses, to estimate heterosis, combining ability and nature of gene action for studied traits under two irrigation regimes. The two irrigation regimes were normal irrigation conditions with amount of applied water 5952.38 m3/ha and water stress conditions with amount of applied water 2976.19 m3/ha at Etay-El-Baroud Agricultural Research Station, Behaira governorate, Agricultural Research Center, Egypt during 2019 summer season. A randomized complete block design with three replications was used for each irrigation regimes. The variation of genotypes and their components from parents, crosses and parents versus crosses were highly significant for all studied traits under both irrigation regimes and their interactions with irrigation. Variation attributable to general and specific combining ability was highly significant for seed yield and yield components under both irrigation regimes. The parents L92 and L110 were the best combiners for seed weight per plant and most of its components under both irrigation regimes. The best F1 cross combination was L92 × L110 in specific combining ability and heterotic effects over mid- and better-parents under both irrigation regimes for seed weight per plant and most of its attributes. The preponderance of additive gene action in the inheritance of most studied traits was observed, that further confirmed by its significance and the value of average degree of dominance exceeding the unity. Narrow-sense heritability varied from 0.19 for number of branches per plant to 0.47 for 1000 seed weight under normal irrigation, whereas, under water stress conditions, it ranged from 0.14 for number of branches per plant to 0.42 for fruiting zone length. Parents L95 and L93 under normal irrigation and L93 and L110 under water stress conditions carried mostly genes with dominant effects for seed weight per plant, in contrary, L92 and L110 under normal irrigation and L92 and L12 under water stress conditions carried mostly recessive alleles for seed weight per plant. Hence, the results will be used to develop a sesame breeding scheme at Etay-El-Baroud Agricultural Research Station.
Denis Paolo Cáceres Candia, Alejandro Risco Mendoza, Patricia Elena Quiroz-Delgado, Walter Eduardo Apaza-Tapia
Peruvian Journal of Agronomy, Volume 5, pp 18-24; https://doi.org/10.21704/pja.v5i1.1670

Abstract:
The flowers blight caused by Botrytis cinerea Pers. is among the most important citrus diseases, especially in cultivars whose flowering coincides with the humid seasons of the year. As a result of the pathogenic features of this fungus and the complex nature of its control, it is necessary to establish a correct plan for the usage of highly efficient fungicides. The study aimed to evaluate the effect of four chemical fungicides, such as Captan (0.25%), Propineb (0.25%), Fludioxonil + Cyprodinil (0.05%), and Iprodione (0.15%); as well as the effect of a biological fungicide, such as Melaleuca alternifolia extract (0.1%), on Botrytis cinerea Pers. Two phases were established: the first, under laboratory conditions of Department of Plant Pathology of National Agrarian University-La Molina (UNALM), evaluated the effect on mycelial inhibition at 1, 3, and 7 days after inoculation with poisoned potato dextrose agar medium. The second, under field conditions (Sayan - Huaura), evaluated the effect on incidence of the disease in flowers. In the field condition, two applications, incidence, and humid chambers were evaluated. The yield was estimated by counting the fruits. The results showed that, under laboratory conditions, Captan, Fludioxonil + Cyprodinil, and Iprodione exhibited high efficacy in the control of B. cinerea. However, under field conditions, Fludioxonil + Cyprodinil and Iprodione exhibited a significant control of B. cinerea. A similar trend was obtained for the yield estimates.
Denis Paolo Cáceres Candia, Alejandro Risco Mendoza, Patricia Elena Quiroz-Delgado, Walter Eduardo Apaza-Tapia
Peruvian Journal of Agronomy, Volume 5; https://doi.org/10.21704/pja.v5i1.1360

Sandro Sardón Nina, Raúl D. Zapata Hernández, Luis A. Arias López
Peruvian Journal of Agronomy, Volume 5, pp 25-34; https://doi.org/10.21704/pja.v5i1.1676

Abstract:
This study compared the organic carbon (OC) content in fractions of humic acids (HA) and fulvic acids (FA) in five soil orders (Aridisol, Entisol, Histosol, Inceptisol and Mollisol) and know their association with the degree of humification. Extraction and fractionation, as well as the degree of humification was carried out by the Nagoya method proposed by Kumada. OC quantification was determined by the Walkley and Black method. The results are: the average OC content of HAs of the order Aridisol differs from that of Histosols, Inceptisols, and Mollisols. The order Entisol presented differences with the Histosols and Mollisols, the soils of the order Inceptisol presented differences with the Aridisols and Histosols and those of the order Histosol differed from the Aridisols, Entisols and Inceptisols. Similarly, those of the Mollisol order differed with the Aridisols, Entisols and Inceptisols. In the fraction of FA the average OC content of the order Aridisol deferred from that found in Histosols, Inceptisols and Mollisols. The Entisol order differed from the Mollisols; likewise, the Inceptisol order differed from the Aridisols and Mollisols and the Histosol order differed from the Aridisols. Finally, the order Mollisol was also different from the Aridisols, Entisols, and Inceptisols. Soil types do not show wetting patterns, because they are not based on pedogenetic processes and these have a wide range of characteristics in surface horizons.
Sandro Sardón Nina, Raúl D. Zapata Hernández, Luis A. Arias López
Peruvian Journal of Agronomy, Volume 5, pp 35-43; https://doi.org/10.21704/pja.v5i1.1680

Abstract:
Humic substances (HS) are the main component of soil organic matter (SOM), a product of the pedogenetic process. In this study, the morphometric factors and climatic variable that condition the degree of humification, the organic carbon content of humic acids (HA) fulvic acids (FA) of 42 soil samples are related through the functional equation of factors of state of the soil proposed by Jenny. The degree of humification was determined by the Nagoya method proposed by Kumada. The quantification of organic carbon was determined using the method by Walkley and Black. The morphometric parameters of the relief were obtained from the Digital Elevation Model (DEM) and the climate parameter of the MODIS sensor. The results show that the relief factor conditions the degree of humification and the climate factor conditions the organic carbon content of humic acids (HA) and fulvic acids (FA).
Jorge Ramón Castillo Valiente, Susana Patricia Rodríguez Quispe, Walter Eduardo Apaza Tapia, Alberto Marcial Julca-Otiniano, Manuel Antonio Canto Saenz, Teresa Rosales Sanchez
Peruvian Journal of Agronomy, Volume 4, pp 75-81; https://doi.org/10.21704/pja.v4i3.1645

Abstract:
The present study was conducted in the fields of the Chavimochic irrigation, located in La Libertad Region-Peru. Prodiplosis longifila Gagné (Diptera Cecidomyiidae) is considered the key pest of asparagus and other vegetables cultivation. This study aimed to characterize the presence of this insect pest in asparagus crop under drip irrigation conditions, in order to find the best alternatives for its control. The cultivar most planted in the Chavimochic Irrigation is cultivar UC 157 and that the meteorological conditions of the area are optimal for the production of asparagus; but also for the establishment and reproduction of the insect. The morphology of asparagus is favorable for reproduction of the insect, from larva to adult, since it frequently bracts and flowers at larval stage and establishs itself at the adult stage; at the base of the plant. All experiments conducted, had at least three repetitions and the results are given on average. The insect can have many hosts and an average biological cycle of 11 days, with the highest populations in the months of May and November. Throughout the day; the adult populations are very active from 10 pm to 4 am. The drip irrigation system provides better conditions for the establishment of the insect and its reproduction in the fields, as well as the design of double row sowing so water management becomes an important factor for managing its populations. From the 100% puparium that fell to the ground, only 37.95% emerged as adults. The percentage of damaged stems per linear meter can be 70.46 and healthy stems 29.54. The number of larvae per shoot can be from 68 to 489 while number of larvae per male flower can be from 2 to 7 individuals. There is a relationship between flowering and the number or pre-pupae fallen to the ground, but as the crop develops, the adult´s number decrease, but nevertheless is still aggressive and permanent.
Peruvian Journal of Agronomy, Volume 4, pp 82-87; https://doi.org/10.21704/pja.v4i3.1649

Abstract:
Climate change is an obvious threat to agriculture, food security and conservation of plant genetic resources. Potato is a globally important food. In Peru, there is high variability and diversity of wild and cultivated species, such that they are considered as one of the region’s most vulnerable to the impact of climate change. With these considerations, we report the results of an investigation in which a preliminary screening of the reaction to drought of 67 native potato morphotypes was conducted to verify for differences in morphological indicators of growth, development, and production of tubers in response to continuous irrigation (CI) and restricted irrigation (RI) treatments. In the course of this study, 21 irrigations were applied to plants by CI (every 1-2 days) and, in the same period, 7 irrigations were applied to plants by RI (every 5-6 days). Comparison of characteristics average in all the morphotypes with plants under CI and RI, indicated that RI did not show differences in height of plants, length of internodes, or leaf and terminal leaflet indexes, and that RI reduced the stem thickness and dry weight of foliage. In this study, we highlight the morphotypes whose plant characteristics present higher averages with respect to their clonal counterparts that were treated with CI. The positive relationship between the number and weight of tubers harvested, as well as the significant reduction of both components of low RI yield is confirmed. In addition, we also highlight the response of some morphotypes that present higher tuber yield under RI. The native morphotypes that were identified as tolerant (according their responses in the characteristics of their plants and yield of tubers under RI) are as follows: BGR 19 (“Rayhuana”); BGR 99 (“Yuracc ñahui hualash”); BGR 170 (“Yana utcush”); and BGR 238 (“Muru huayro”).
Kripa Adhikari, Sudip Bhandari, Laxmi Dhakal, Jiban Shrestha
Peruvian Journal of Agronomy, Volume 4, pp 121-133; https://doi.org/10.21704/pja.v4i3.1495

Abstract:
Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), Fall Armyworm (FAW) is a crop pest with more than 80 host species causing severe damage to maize cereals. FAW, native to the tropical and subtropical region of America, has rapidly spread worldwide. The larvae and adults of FAW damage young leaves, leaf whorls, tassels or cobs of maize. Under heavy infestation of FAW cause 50-80% yield loss in maize crop. This pest is capable of rapidly breeding, migrating and feeding on a large variety of host plants, making it very difficult to monitor. However, there are several control measures reported in various countries. Integrated pest management (cultural, chemical, and biological) is widely used to control this pest. Because the pest has become resistant to many insecticides, its use is not recommended at the initial stages of infestation. But, the last choice for this seriously infested pest management is the use of pesticides below the economic threshold level. This review focuses on insect distribution, biology, maize damage, and possible strategies for its management.
Ernesto Díaz-López
Peruvian Journal of Agronomy, Volume 4, pp 88-92; https://doi.org/10.21704/pja.v4i3.1650

Abstract:
In order to know the effect of three levels of potassium on five eco-physiological parameters in sunflower, open-pollinated achenes Victory cultivar, were sown at a density of 11.08 plants m-2 with a fertilization of 100N-50P kg ha-1 N=nitrogen, P= phosphorous, K= potassium. Traits evaluated were: agronomic yield, leaf area index, light attenuation coefficient and intercepted radiation. The treatments consisted of three potassium levels: 0, 50 and 100 kg ha-1 (K2O) and four repetitions (3x4) resulting in 12 experimental units, which were evaluated under a randomized complete block design. The results indicate that the application of 50 and 100 kg ha-1 of potassium increase the agronomic yield, leaf area index, intercepted radiation as well as the light attenuation coefficient. From this investigation it can be concluded, that potassium is a very important nutrient for sunflower when it is sown in dry climates such as the Tehuacan valley, Puebla.
Juan Nolasco-Chumpitaz, Paul Ccoyllo-Llacsa, Gabriela Koc-Sanchez, Percy Medina-Morales
Peruvian Journal of Agronomy, Volume 4, pp 93-103; https://doi.org/10.21704/pja.v4i3.1341

Abstract:
The aim of this study was to characterize and identify groups of achiote (Bixa orellana L.) with characteristics related to increased yield and bixin content. A total of 149 achiote accessions were collected from the departments of Loreto, San Martin, Junín, Pasco, Huánuco, Ucayali, and Cusco, in Perú. These were then evaluated using ten quantitative and three qualitative capsule and seed descriptors. Undesirable characteristics such as high spinosity and dehiscence predominated, while none of the quantitative descriptors correlated significantly with bixin content. Principal component analysis indicates that the quantitative descriptors (except for bixin content) are statistically significant, forming four clusters. Notably, one of the clusters included accessions characterized by heavy seeds, and another cluster included accessions with high number of seeds and bixin content.
Shruti Shrestha, Sudeep Subedi, Jiban Shrestha
Peruvian Journal of Agronomy, Volume 4, pp 104-120; https://doi.org/10.21704/pja.v4i3.1490

Abstract:
Plant breeders and geneticists use molecular marker-assisted selection also called as MAS as a useful approach for breeding of plant to make selection more efficient and speed up the breeding cycle. MAS can be more efficient, effective, and reliable than phenotypic selection. Molecular markers are useful to identify the economically important traits in the breeding population for further manipulation in a short time. Due to the applicability of markers at the seedling stage ensuring high precision at the reduced level of cost, marker-assisted selection offer the chances to improve responses from selection. The MAS using DNA level polymorphism accelerate the pace of selection. The main marker technologies applied are chiefly co-dominant markers i.e. microsatellite markers/SSR (Simple Sequence Repeats) marker, RFLP (Restriction Fragment Length Polymorphism) marker and SNPs (Single nucleotide polymorphisms). This review overviews the various MAS technologies and their applications in crop improvement programs.
José E. Salas-Rosales, Pedro Manuel Villa, Alice C. Rodrigues, Fermín Rada
Peruvian Journal of Agronomy, Volume 4, pp 68-74; https://doi.org/10.21704/pja.v4i2.1571

Abstract:
Nitrogen fertilization has positive effects on growth and production of potato crop. The objective of this study was to assess the differences of the photosynthetic response and biomass partitioning patterns during the main phenophases of the potato cultivar Capiro under different nitrogen nutrition fertilization treatments in the tropical Andes of Mérida, Venezuela. Plots of 40 m2 (2,625 plants m-2) were established under a random block design with three replications by nitrogen fertilization treatment: 0, 100, 200, and 300 kg. N ha-1. Photosynthesis and biomass were measured in the different organs in the main phenological stages of the crop. The results indicate that photosynthesis tends to increase slightly with the nitrogen supply; although the differences were not always significant and, decreases during crop growth. Tubers yield it was markedly influenced by the nitrogen fertilization. The total biomass production, as well as biomass allocation in different organs showed differences between treatments, maintaining the following order: 300-N> 200-N> 100-N> 0-N. When analyzing the biomass accumulation curves, it is estimated that the application of 250 kg N ha-1 as mineral fertilizer is enough to reach optimal production yields.
Juan Flores-Bernedo, Javier Vásquez-Castro
Peruvian Journal of Agronomy, Volume 4, pp 61-67; https://doi.org/10.21704/pja.v4i2.1546

Abstract:
The use of inhibitors of lipids synthesis is among the available strategies for the control of Tetranychus urticae (Acari: Tetranychidae) in strawberry plantations. The study aimed to monitor the susceptibility to Spirodiclofen in field populations of T. urticae from strawberry plantations in Lima region, Peru. Adult T. urticae were collected from strawberry plantations in districts of Aucallama, Chancay, Huaral, and Santa Rosa de Quives in Lima region, Peru. A population collected from Acalypha wilkesiana in campus of the Universidad Nacional Agraria La Molina (UNALM), where chemical pesticide has never been applied, was used as a susceptible reference line. This reference line was subjected to toxicological bioassays to estimate the LC50 and LC95. Afterward, bioassays were conducted on the population using the LC50 and LC95 estimated for the susceptible reference line. The obtained data was subjected to one-way analysis of variance and mean comparison was done by Tukey test (α = 0.05). There were no significant differences between the four populations’ LC50 and LC95, with respect to the estimated susceptible reference line. This implies that the four studied populations of T. urticae are susceptible to Spirodiclofen, with no evident resistance problems. Therefore, Spirodiclofen is a useful tool for the control of T. urticae form strawberry plantations in the studied location. The factors that influenced the results are discussed in the present work.
J. Vásquez-Castro, G. De Baptista, C. Gadanha-Junior, J. Bracho-Pérez
Peruvian Journal of Agronomy, Volume 4, pp 40-47; https://doi.org/10.21704/pja.v4i2.1510

Abstract:
Chemical insecticides are commonly used to control insect pests in stored wheat. However, the presence of insecticide residues in food may endanger consumers. We studied the degradation and persistence of two insecticides, fenitrothion and esfenvalerate, in wheat grain, bran, and flour. The application system was calibrated to treat grain at theoretical concentrations of 10 and 0.5 mg kg−1 of fenitrothion and esfenvalerate, respectively. Samples treated with the insecticide mixture were collected at 0, 15, 30, 60, 90, 120, 180, 240, and 360 days after treatment. Samples were analyzed quantitatively by gas chromatography with an electron capture detector (ECD, Ni63). The experimental design was completely randomized with three replicates. Esfenvalerate was more persistent than fenitrothion, with the residues of both insecticides concentrated mainly in the bran, and with least amounts in the flour. The concentrations of fenitrothion residues during the 120-day preharvest interval exceeded the maximum residue limit (MRL) of 1 mg kg−1 set by Brazilian legislation. We discuss the factors that influence the degradation/persistence of fenitrothion and esfenvalerate.
Marilena Marconi, Javier Ormeño Luna, Carlos Daniel Vecco Giove
Peruvian Journal of Agronomy, Volume 4, pp 55-60; https://doi.org/10.21704/pja.v4i2.1541

Abstract:
The honeys from stingless bees (Hymenoptera: Apidae: Meliponini) are recognized for their medicinal properties. They are commonly used by many indigenous groups around the world. However, in Peru stingless beekeeping is practiced in an artisanal way and the honeys remain products whose qualities are still little studied. The objective of this work was to analyze physicochemical characteristics and microbiological quality of honeys produced by Scaptotrigona polysticta Moure, Melipona illota Cockerell and Tetragonisca angustula Latreille in apiaries of department of San Martin, Peru. In June and November 2019, 30 honey samples were collected from 24 colonies housed in two apiaries in the towns of Tarapoto and Chasuta. Significant differences (p 10 CFU / mL) according Peruvian sanitary norm № 071-Minsa/Digesa-V.01, in 30 and 50% of the samples of S. polysticta and T. angustula, respectively. These results contribute to the knowledge of the stingless bee honeys of Peru providing important references for the quality standard setting process and the advancement of stingless beekeeping.
Sergio Eduardo Contreras-Liza, Eroncio Mendoza-Nieto, Jean Pierre Quiliche Durán, Cecilia Maura Mejía-Domínguez, Betty Martha Palacios-Rodriguez, Julia Delia Velasquez Gamarra
Peruvian Journal of Agronomy, Volume 4, pp 48-54; https://doi.org/10.21704/pja.v4i2.1533

Abstract:
The objective of this investigation was to evaluate the effect of inoculating Azospirillum sp. and two levels of nitrogen on the productive characteristics of hard yellow corn variety ‘Insignia 800’ under the conditions of Nuevo Imperial, Cañete (central coast of Peru). A randomized complete block design with five treatments and four replications was used in a field experiment using the commercial corn hybrid ‘Insignia 800’. The treatments were two levels of nitrogen (90 and 180 kg N ha-1), plus one or two applications to the foliage of Azospirillum sp. (1.08 x 107 CFU per plant), and a control treatment (without inoculation). Ten agronomic variables related to productive traits were evaluated. Treatment comparison was executed with the Scott Knott test at the 5% significance level using the Infostat program. Inoculation with Azospirillum sp. did not significantly affect the grain yield per hectare, grain weight per plot, shelling percentage, grain depth, number of ears per plant and diameter of the cob, but it influenced significantly some productive traits such as cob weight per plot, grain weight per plant, cob diameter and ear length, as well as a high benefit-cost ratio due to inoculation. Inoculating the plant foliage with Azospirillum sp. had a significant effect and greater economic efficiency for some productive characteristics of the hard yellow corn cv. ´Insignia 800´, and did not significantly affect grain yield.
, G. Sánchez
Peruvian Journal of Agronomy, Volume 4, pp 1-9; https://doi.org/10.21704/pja.v4i1.1438

Abstract:
Sweetpotato (Ipomoea batata L.) is an economically important crop grown in Peru. The present study aimed to determine the soil arthropods associated with sweetpotato and its relative abundance in sweetpotato production fields in La Molina, Lima, Peru. Evaluations were conducted at Universidad Nacional Agraria La Molina, from February to August 2017. Samples were collected using pitfall traps and examined at the Klaus Raven Büller Entomology Museum. Soil morphospecies were extracted and separated from collected samples and then counted, recorded and identified. They were also admitted to the Entomology Museum collection. Eighty morphospecies in the classes Collembola, Insecta, Malacostraca, Arachnida and Chilopoda of phylum Arthropoda were recorded. Within the Collembola class, Entomobryidae was the most abundant family; within Insecta, Gryllus spp. (Gryllidae); within Malacostraca, Porcellio laevis (Porcellionidae); within Arachnida, Theridion volubile (Theridiidae) of the order Aranea; and within Chilopoda, the order Lithobiomorpha. By understanding the diversity of arthropods, it may inform future measures and improve control of pests by taking into consideration the soil arthropods among which important beneficial natural enemies could be found.
, L. Tello
Peruvian Journal of Agronomy, Volume 4, pp 27-34; https://doi.org/10.21704/pja.v4i1.1462

Abstract:
Phytoremediation is a potentially less costly approach to treat contaminated soil. Here, the phytoremediation capacity of marigold (Tagetes erecta) in conjunction with EDTA and mycorrhizae was analyzed. Specifically, the ability of the marigold to extract lead from contaminated soils in the Bird Forest Zone of the Huachipa Zoological Park (PZH) was evaluated. Marigold was planted in main areas of interest within the PZH. Plants were treated with different concentrations of mycorrhizae (0 and 0.5 g/kg) and EDTA (0, 0.5 and 1 mg/kg) and later analyzed by atomic absorption spectrophotometry for lead concentrations in the aerial parts and roots of the plants at the end of the experiment. We show that marigold has the ability to extract lead; and under the conditions of the experiment, mycorrhizae did not improve the extraction efficiency. However, EDTA did increase the amount of lead extracted, thus affecting the physiological development of the plant.
J. Vásquez-Castro, A. Ancco, B. La Torre
Peruvian Journal of Agronomy, Volume 4, pp 35-39; https://doi.org/10.21704/pja.v4i1.1464

Abstract:
Asparagus (Asparagus officinalis L.) is a difficult crop to treat with spraying pesticides because its architecture makes it difficult for droplets to penetrate inside of the canopy, where its pests are located. This study aims to examine the influence of operational parameters, such as nozzle inclination and application rates on the inner side of the canopy. We installed nozzles in the spray boom and its droplegs in three different inclinations: 0° with the plant, 30° in the direction of movement of the tractor-sprayer assembly (+30°), and 30° in the opposite direction (−30°). We applied the mixture in application rates of 600, 900, and 1,200 L ha−1. More so, the regulation used by the farmer of 0° and 800 L ha−1 was applied as a control. Copper (Cu) was used as a tracer for the mixture in a dose of 13.5 g ha−1. Also, non-plasticized polyvinyl chloride grooved tubes (PVC) were installed inside the asparagus canopy and polyethylene sheets were placed on the pipes at different heights from the ground. Later, we analyzed the sheets with atomic absorption spectrophotometry. Results showed that the nozzle inclination and sampling height had notable effects on the copper deposit. Conversely, different application rates showed no varied effects significantly. The greatest copper deposition in the asparagus canopy was achieved with a nozzle inclination of +30° with any application rate. Finally, we recommend regulating the sprayers with a nozzle inclination of +30° and an application rate of 600 L ha−1 as the most effective adjustment for the distribution of pesticides and represent the lowest cost of operation since there is no influence of the application rate.
René Aguilar Anccota, L. Mattos-Calderon
Peruvian Journal of Agronomy, Volume 4, pp 17-26; https://doi.org/10.21704/pja.v4i1.1461

Abstract:
Gypsophila is an ornamental plant whose flowers are economically important, which is cultivated in the Callejón de Huaylas valley-Ancash. Recently, cultivated Gypsophila fields have shown diseased plants characterized by stem base rot, which has been followed by a reduction in vigor and the collapse and death of plants. Therefore, the objectives of this research were to describe the symptomatology of the disease, identify the causative agent of the disease, and prove how effective fungicides and biological control agents (BCA) are in controlling the disease using in vitro and field experiments. To isolate the pathogen, symptomatic plant tissue samples were washed, cut into small pieces, disinfected in 1% sodium hypochlorite solution for 1 min, rinsed twice with sterilized water, and air-dried on paper towels. The samples were seeded on Petri dishes containing potato dextrose agar media and incubated at 25 °C. A pathogenicity test was conducted in healthy Gypsophila seedlings, which were grown in a sterilized substrate, using mechanical inoculation on the stem base and agar disks colonized by the pathogen-mycelium. Then the pathogen was reisolated from symptomatic inoculated Gypsophila seedlings. The “poisoned medium” technique was used to conduct the in vitro fungicide test, while the “dual method” was used to conduct the bio controller’s test. The results of the pathogenicity test and in vitro and field experiments showed that Rhizoctonia solani is the causative agent of the stem base Gypsophila disease, and at both assayed doses, the fungicides Rovral, Benopoint, Parachupadera, Vitavax, and Homai completely inhibited the mycelial growth of R. solani. Moreover, the BCAs Trichoderma harzianum and T. viride showed higher in vitro growth rates than R. solani and completely colonized the pathogen-mycelium. Under field conditions, the incidence of the disease in field plots treated with T. harzianum was 12.5% lower than in the control treatment, which showed 51.28% incidence of the disease. In addition, Gypsophila plants harvested from plots treated with T. harzianum exhibited higher numbers of flower stalks per plant and a higher fresh weight compared to the control treatment.
B. Morales, J. Bautista, C. Vergara
Peruvian Journal of Agronomy, Volume 4, pp 10-16; https://doi.org/10.21704/pja.v4i1.1451

Abstract:
This survey aimed to determine the pollinating insects of the flowers of the cherimoya crop (Annona cherimola Mill.) located at the Program of Research and Social Projection in Fruit Trees (PIPS-FRUTALES) at the Universidad Nacional Agraria La Molina. Fifteen trees were selected randomly, and evaluations were performed from 31 October to 15 November 2018. Three replicates were performed, each replicate was formed by a set of five trees and were evaluated in three different weeks. Each tree was evaluated in four quadrants, according to the location of the flowers (external or internal) and the floral phases of the crop (female or male). The collection of the insects from the cherimoya flowers was performed using an aspirator, then the insect morphotypes were determined and classified according to order, family, genus and/or species through the use of taxonomic dichotomous keys and the support of specialists. The collected insects belonged to the orders Coleoptera, Hymenoptera, and Hemiptera, with Coleoptera having the highest diversity (17 morphospecies) and quantity (242 specimens). The genus Europs (Monotomidae) proved to be the most abundant group of Coleoptera during the assessment period, followed by morphospecies of the families Nitidulidae, Anthicidae, Staphylinidae, Scarabaeidae, Anobiidae, and Buprestidae. The pollinating insects present in the cherimoya crop were satisfactorily classified into genera and species.
J. Bracho-Pérez, I. Tacza-Valverde, J. Vásquez-Castro
Peruvian Journal of Agronomy, Volume 3, pp 126-133; https://doi.org/10.21704/pja.v3i3.1206

Abstract:
Daphnia magna is proposed as a bioindicator to establish the minimum concentration capable of controlling pests before performing toxicity tests. This study uses the proposed pest control extracts of two Peruvian species, Clibadium peruvianum Poepp. (seeds) and Petiveria alliacea L. (leaves). The toxicological effects of the plant extracts were evaluated with D. magna, using five neonates over a period of 24–48 h. A lack of mobility or the absence of heart rhythm for 15 s under a stereomicroscope was considered to indicate mortality. Organic extracts were discarded due to their higher toxicity when compared with the aqueous extracts of C. peruvianum and P. alliacea, which had LC50 = 460.74 mg/L and LC50 = 711.18 mg L−1 at a concentration of 10 mg L−1, respectively. Using this Daphnia-safe concentration, toxicity tests were performed on the third instar larvae of Musca domestica (housefly). Higher activity was observed with an aqueous extract of seeds of C. peruvianum and a leaf aqueous extract of P. alliacea, showing 58.33% and 56.7% mortality against M. domestica, respectively. Both extracts induced abnormal changes in the development of the housefly, causing deformation, burns, and dehydration of tissues in the larvae. It is evident that using D. magna as a preliminary toxicological test allows the determination of concentrations that are safer to use while maintaining the activity of the extracts as a botanical biopesticide, thus posing the lowest risk to the environment, ecosystems, their species, and human health.
Peruvian Journal of Agronomy, Volume 3, pp 134-143; https://doi.org/10.21704/pja.v3i3.1207

Abstract:
In this paper, the floristic composition is studied in plots of early post-agricultural succession induced in four agroecosystems (Ocopata, Rancas, Tupicocha and Ucupi) in the district of Cajatambo, Lima. The plots are located between 2,992 masl and 4,220 masl in three plant formations (agriculture, scrubland and grassland), and the description of the floristic composition was made before and after inducing the succession between 2015 and 2017. The number of determined plants is 78, all of which belong to 30 botanical families, of which the Asteraceae (16 species), Fabaceae (11 species) and Poaceae (8 species) families stand out. Indeed, the only common species among the four agroecosystems is Medicago polymorpha; moreover, five species appear in three of the four agroecosystems: Brassica rapa subsp. campestris and Verbena litoralis (Ocopata, Tupicocha and Rancas), Oenothera rosea and Trifolium repens (Ocopata, Rancas and Ucupi) and Bidens andicola (Tupicocha, Rancas and Ucupi).
A. Eguiluz, Rember Pinedo, C. Figueroa
Peruvian Journal of Agronomy, Volume 3, pp 120-125; https://doi.org/10.21704/pja.v3i3.1209

Abstract:

To evaluate the behaviour of cassava clones (Manihot esculenta Crantz), the physiological quality of the propagation material was assessed, and an agronomic characterisation was conducted; this was essential for the generation of information on the clones’ productive potential. The trial was conducted in the experimental field of the Roots and Tubers programme (PIPS-RT) of the National Agrarian University–La Molina. Following a completely randomised block design with four replications, clones from the PIPS-RT were evaluated. Variables were assessed to determine the clones’ physiological quality in terms of the number of viable stakes, normal seedlings, abnormal seedlings and percentage of stake survival. The agronomic characteristics evaluated were plant height, stem diameter and yield. The Morocha clone had the highest percentage of viable stakes and normal seedlings, i.e. 80.95% and 73.81%, respectively. The highest yield was also produced by the Morocha clones (13 t/ha) followed by the Donoso 2 (7.20 t/ha) and Blanca Cajamarca (6.80 t/ha) varieties.
M. Castro, T. Nishikawa
Peruvian Journal of Agronomy, Volume 3, pp 112-119; https://doi.org/10.21704/pja.v3i3.1251

Abstract:
Lily (genus Lilium) is one of the most important flowers for bulb and cut flower production in the world. Lilium rubellum Baker is a native species of Japan that exhibits early flowering, is pink coloured, and possesses a pleasant fragrance, which makes it an important genetic resource for breeding lilies. In this work, the genetic diversity of L. rubellum was studied among three natural populations located in Fukushima Prefecture, Japan, which have been designated as the Mt. Azuma, Nango and Atsushio-kano populations. A total of 31 accessions collected in 1997 were analysed using Random Amplified Polymorphic DNA (RAPD) markers. Eighteen decamer primers produced 98% polymorphic RAPD bands; furthermore, 11 of the 18 primers produced 10 or more polymorphic bands with a mean per primer Polymorphic Information Content of 0.382. Among the three populations, the mean Shannon index, Nei´s gene diversity and percentage of polymorphic loci were 0.2749, 0.4099 and 76.7%, respectively. These data revealed that there is a high genetic diversity within all the populations. Analysis of the three genetic diversity indices within populations showed that the Nango population had the highest genetic diversity, whereas the Atsushio-kano population had the lowest. An unweighted pair group method with arithmetic mean dendrogram based on Jaccard´s similarity coefficient was constructed, and the three populations of L. rubellum collected in the Fukushima prefecture were clearly differentiated at 0.61 similarity index. The Nango and Mt. Azuma populations were genetically closer than the Atsushio-kano population. The analysis of molecular variance showed a 29.53% variance among the populations. This study revealed that there is high genetic diversity within populations and moderate genetic diversity among the three natural populations of L. rubellum Baker in the Fukushima Prefecture of Japan.
J. Soto, C. Cadenas, L. Mattos, C. Trigoso
Peruvian Journal of Agronomy, Volume 3, pp 144-152; https://doi.org/10.21704/pja.v3i3.1367

Abstract:
The objective of the present research was to identify the causal agent of soft rot disease in the stems of pitahaya plants (Hylocereus undatus (Haw.) Britton & Rose), also known as dragon fruit, in two production areas of Peru. Typical symptoms observed include rotting and soft consistency in stems, as well as yellowish colourations, which usually begin at the tips and outer edges of the stems and extend until they are completely decomposed. Symptomatic samples of pitahaya stalks were collected from two commercial fields, the first from the district of Independencia, Pisco, Ica, and the second from the district of Naranjos, Rioja, San Martin. The collected samples were transferred to the phytopathology laboratory of the National Agrarian University – La Molina where 19 bacterial colonies isolated from symptomatic stem tissue were processed. Nine bacterial colonies were selected from the initial 19 for further analysis. The nine selected colonies were gram negative, positive for the catalase enzyme, negative for the enzyme oxidase, and positive for pectinase production, which causes soft rot in potato tubers. These results indicated that these isolates correspond to the Enterobacteriaceae family. According to molecular tests and analysis of the 16s region of ribosomal DNA, all bacteria corresponded to a single taxonomic genus, Enterobacter. This bacterium presented a 99.85% homology with Enterobacter cloacae (accession number MH788982.1). The sequences from the nine selected isolates were entered into GenBank under accession number MN784371. In the pathogenicity test, 100% infection was obtained in the pitahaya stems and plants inoculated with E. cloacae, and the symptomatology that developed was the same as that observed in the two fields from where the samples were collected. Given these results, it can be concluded that E. cloacae is a causative agent of soft rot disease of the stems of H. undatus in the districts of Independencia and Naranjos, and this is also the first report of this bacterium as a pathogen of pitahaya in Peru.
W. Apaza, P. Quiroz, A. Julca-Otiniano
Peruvian Journal of Agronomy, Volume 3, pp 91-103; https://doi.org/10.21704/pja.v3i3.1342

Abstract:
The Chavimochic irrigation project is one of the leading projects in Peru. In this project, irrigation water is derived from the Santa river to irrigate the valleys of Chao, Viru, and Moche, including desert zones between valleys. In this study, we aimed to characterise the Hass avocado and asparagus farms in desert areas of the Chavimochic irrigation project. Social, economic and environmental information was collected through structured surveys of 12 asparagus and 17 avocado farms. Four groups of asparagus farms and three groups of avocado farms were identified based on principal component and cluster analyses. Profitability of the avocado crop was higher than that of the asparagus crop, and irrigation caused more significant variability in the crop yield of avocado than that of asparagus. From the social perspective, the income of farm personnel was related to the level of education, and female personnel showed more participation in the Chavimochic irrigation project than in other agroecosystems of Peru.
J. Condor, J. Olivera, Rember Pinedo
Peruvian Journal of Agronomy, Volume 3, pp 104-111; https://doi.org/10.21704/pja.v2i3.1229

Abstract:
Garlic (Allium sativum L.) is an important crop for domestic consumption in Peru. However, there is insufficient information available on crop management, particularly on fertiliser application to local cultivars. In order to evaluate the response of three garlic cultivars to three fertilisation methods, an experiment was conducted at the Donoso Experimental Station in Huaral district, a province of Lima. Three garlic cultivars were used as experimental materials: ‘Cincomesino’, ‘Arequipeño 14’ and ‘Margosino’. Three methods of fertilisation were applied as treatments: broadcast application before furrowing (M1), fertilisation in a superficial groove or false furrow (M2), and fertilisation in the lateral furrows, or band application (M3). The experiments were installed in three parcels for each cultivar, with a randomised complete block design for each parcel and four replications. In general, localised fertilisation methods showed the best performance for the broadcast method. Regarding total yield, fertilisation at the sides of the furrow (M3) for ‘Cincomesino’ reached 13.08 t/ha. The highest yield for the ‘Arequipeño 14’ cultivar (12.25 t/ha) was achieved using fertilisation with a surface groove or false furrow (M2). For the ‘Margosino’ cultivar, fertilisation on the sides of the furrow was ideal, and the yield was 10.95 t/ha.
E. Mamani, M. Román, M. Gonzales
Peruvian Journal of Agronomy, Volume 3, pp 81-90; https://doi.org/10.21704/pja.v3i3.1339

Abstract:
De Siguas, Arequipa Province, Peru. The concentrations used were 2, 4, and 6 kg ha−1 with 4 applications by means of impregnation to the transplant and via drench every 15 days. The statistical design was through a DBCA with factorial arrangement randomly distributed in four blocks. The tests used were the orthogonal contrast test and Duncan’s multiple comparison test (α = 0.05). The findings showed that the treatment concentrations of 4 kg ha−1 and 6 kg ha−1 resulted in a lower incidence of Fusarium oxysporum, at 6.71% and 9.36%, an ABCPE of 637.78 and 950.14 units, and an exportable yield of 66.34 t ha−1 and 65.42 t ha−1, respectively, displaying significant differences from the control. The first application was statistically significant to the treatments with the highest number of applications, showing a greater exportable yield of 67.54 t ha−1. The best interactions between concentrations and applications were 6 kg ha−1 with 1 application, 4 kg ha−1 with 2 applications, and 4 kg ha−1 with 1 application, with exportable yields of 70.66, 69.61, and 69.11 t ha−1, respectively.
W. Ojeda, R. Borjas, L. Alvarado, V. Castro-Cepero,
Peruvian Journal of Agronomy, Volume 3, pp 68-73; https://doi.org/10.21704/pja.v3i2.1316

Abstract:
The objective of this study was to determine the allelopathic effects of leaf extracts of the forest species guaba (Inga edulis) and cadaghi (Corymbia torrelliana) on coffee (Coffea arabica ‘Caturra Roja’) plants grown under nursery conditions in Chanchamayo, Peru. Different doses of fresh leaf extracts were applied to coffee plants using a completely randomized design, with four treatments for each forest species (T1 = 0‰, T2 = 10‰, T3 = 20‰, and T4 = 30‰) and 12 replicate plants per treatment. It was found that none of the foliar extracts had an allelopathic effect on coffee plants in terms of height, stem diameter, number of leaves and dry weight; however fresh weight was significantly altered following “cadaghi” treatment.
, L. Mattos
Peruvian Journal of Agronomy, Volume 3, pp 57-67; https://doi.org/10.21704/pja.v3i2.1315

Abstract:
Strawberry (Fragaria ananassa) plants showing symptoms of leaf spot were found in the producing areas of Manchay Bajo, Pachacamac District, Lima, Peru. The responsible pathogen was isolated and observed under a microscope to examine its morphological characteristics and the size of its structures, resulting in its identification as the fungus Corynespora cassiicola. Healthy strawberry plants that had been inoculated with C. cassiicola in a greenhouse developed lesions after 3 days and exhibited symptoms consisting of dark brown spots that had light brown centers and were surrounded by yellow halos, which coalesced and subsequently caused necrosis of the whole leaf. In vitro tests demonstrated that the fungus Trichoderma harzianum strain T-22 showed antagonistic activity against C. cassiicola, causing 41.8% mycelial growth inhibition, and the fungicides fosetyl-aluminum (Aliette®) and thiabendazole (Mertect®a) inhibited mycelial growth by 100.00% and 96.32%, respectively. However, in vivo, 0.75 g/L of the fungicide azoxystrobim (Stronsil®) gave the best control of C. cassiicola and the lowest area under the disease progress curve (AUDPC), followed by 1.5 mL/L of thiabendazole (Mertect) under greenhouse conditions. The isolate was found to be pathogenic, and its morphological identification was confirmed.
V. Quintana, L. Alvarado, D. Saravia, R. Borjas, V. Castro-Cepero, , L. Gómez
Peruvian Journal of Agronomy, Volume 3, pp 74-80; https://doi.org/10.21704/pja.v3i2.1317

Abstract:
The effects of gamma radiation on the germination, survival, and morphological damage in characteristics of the M1 generation of coffee (Coffea arabica L. var. typica) plants was evaluated using seeds collected from Santa Teresa and Chaupimayo, Peru. Under net house, the percentage of germination was 68%, 35%, 10%, and 0% for the Santa Teresa seeds and 75%, 49%, 17% and 0% for the Chaupimayo seeds with irradiation treatments of 0, 50, 100 and 150 Gy, respectively, whereas under laboratory conditions, germination levels were between 70% and 94% across all treatments. The survival rate also decreased with increasing radiation levels, with values of 45%, 32%, 28%, and 10% in the laboratory and 29%, 9%, 6%, and 0% in the net house for the Santa Teresa seeds and 58%, 45%, 38%, and 8% in the laboratory and 42%, 15%, 7%, and 0% in the net house for the Chaupimayo seeds with irradiation treatments of 0, 50, 100, and 150 Gy, respectively. Morphological changes were observed in the plants that survived irradiation at a dose of 100 Gy in terms of the leaf shape, leaf apex shape, young leaf color, plant height, stem diameter, number of leaves per plant, leaf length, leaf width, and distance from the cotyledon to the first node.
, L. Tello
Peruvian Journal of Agronomy, Volume 3, pp 39-46; https://doi.org/10.21704/pja.v3i2.1313

Abstract:
In Peru, gasoline containing lead as a main component was used in vehicles up until 2006, when the Government banned its sale. However, since this was preceded by a century of constant use, there is a high chance that most urban soils are polluted with this heavy metal. Hyperaccumulator plants that take up heavy metals from the soil and store them in their tissues without showing any symptoms of toxicity may be the solution to this problem, as the use of these plants for phytoremediation does not require large amounts of money, can be carried out in situ, and is environmentally friendly, making it one of the best options for urban areas. However, unfortunately, there are only a few known species of hyperaccumulator plants that can be grown in urban environments. Therefore, we conducted a bioassay at the Soil Fertility Laboratory of the Agronomy Faculty at the National Agrarian University La Molina, Peru, over a period of 4 months to determine the hyperaccumulation capacity of Salvia splendens ‘Red Vista’ and to examine whether the mycorrhizal fungus Glomus intraradices can enhance the extraction of lead from the soil. After harvest, the plants were divided into three parts (roots, leaves, and inflorescences) to determine the concentrations of lead in the various tissues. We found that S. splendens ‘Red Vista’ did not accumulate high amounts of lead in its tissues even when it was associated with G. intraradices and consequently should not be considered for use in phytoextraction.
C. Martinez-Martinez,
Peruvian Journal of Agronomy, Volume 3, pp 47-56; https://doi.org/10.21704/pja.v3i2.1314

Abstract:
In Integrated Pest Management practices, knowledge from multiple disciplines is incorporated to facilitate the understanding of a problem and the development a practical, feasible, and ecologically sustainable solution. A froghopper (Aeneolamia spp.) plague can trigger major economic losses in sugarcane plantations in countries such as El Salvador and others in Latin America. Losses are often due to a lack of understanding of the life cycle of a pest and the underestimation of its annual reproductive potential. An algorithm was developed to model the most relevant aspects of froghopper reproduction and its interactions with the environment, to facilitate the prediction of potential increases in adult populations and its propagation in fields. Data on several biological variables were collected as numerical measures and used to perform calculations based on a mathematical model designed particularly to simulate the reproduction of the pest, its economic threshold, and potential losses due to major natural events, with the aim of developing a tool that could support decision-making. The predictions of the tool were consistent with the findings of other studies in the field. The software and its installation instructions can be downloaded for free from https://drive.google.com/file/d/1oUWTTbi lWMhoFuTH4wCKtuzjFwDd89/view
A. Carrión, M. De L. Tapia
Peruvian Journal of Agronomy, Volume 3, pp 24-28; https://doi.org/10.21704/pja.v3i1.1281

Abstract:
The potato (Solanum tuberosum L.) is important as both a food and a source of economic activity in Peru. However, potato production is limited by seed quality and other biotic and abiotic factors. We explore a new alternative method for producing prebasic seeds of Peruvian potato varieties known as temporary immersion bioreactors (BIT). The process of producing potato microtubers using BIT consists of two phases: proliferation and microtuberization. During the proliferation phase, we seeded six nodal segments of three nodes in a liquid culture medium with 30 g of sucrose under a photoperiod of 16 light hours and eight dark hours. This phase also included an irrigation cycle of five minutes every three hours for 30 days. During the microtuberization phase, the conditions were changed to a medium with 80 g of sucrose in darkness, and the same irrigation cycle was used for 60 days. Under these conditions we obtained 20, 18.4, 13.4, 13.4, and 4.6 microtubers of the varieties Peruanita, Canchan, Capiro, Unica, and Yungay, respectively.
C. Livia, G. Sánchez
Peruvian Journal of Agronomy, Volume 3, pp 16-23; https://doi.org/10.21704/pja.v3i1.1279

Abstract:
This study aimed to determine the composition and relative abundance of soil insects associated with lucumo (Pouteria lucuma L.) trees growing in the agricultural fields of the Universidad Nacional Agraria La Molina in Lima, Peru. In total, 12 pitfall traps were installed in a 5-ha lucumo field and samples were collected on a weekly basis for approximately 4 months (March–June). Insects in each sample were separated into morphotypes, and the number of individuals in each morphotype and date of collection were recorded. The collected insects were then identified at the Entomology Museum laboratory in Lima through comparison with museum samples and with the help of identification keys. Individuals in the orders Orthoptera (families Acrididae and Gryllidae), Dermaptera (Anisolabididae), Coleoptera (Carabidae, Staphylinidae, Tenebrionidae, Scarabaeidae and Elateridae), Blattodea (Blatellidae) and Hymenoptera (Formicidae) were identified. Among the Coleoptera, Tetracha chilensis (Laporte, 1834) (Carabidae) was the most abundant species; furthermore, Staphylinidae of the subfamily Oxytelinae and the families Elateridae (Conoderus spp.), Tenebrionidae (Epitragopsis sp.) and Scarabaeidae (Ataenius sp.) were identified. Additional taxa identified were as follow: Gryllus assimilis (Fabricius, 1775) (Gryllidae) in Orthoptera, Euborellia annulipes (Lucas, 1847) (Anisolabididae) in Dermaptera and Linepithema spp. in Hymenoptera.
E. Catacora, J. Olivera, Z. Ramos, Z. Alve, R. Pinedo
Peruvian Journal of Agronomy, Volume 3, pp 29-38; https://doi.org/10.21704/pja.v3i1.1280

Abstract:
The aim of the study was to evaluate the in vitro propagation ability of 10 clonal lines of thorny globe artichoke (Cynara scolymus L.). The study methodology comprised five stages of evaluation. The stages evaluated were initiation, multiplication, rooting, acclimatization, and transplant to the field. The study began with the initiation of dissected shoot tips of 10 clonal lines in test tubes containing the Murashige and Skoog (MS) medium. Best results were obtained when explants were cultured on an induction medium containing MS + naphthalene acetic acid (NAA) 1.0 mg l−1 + benzyl aminopurine (BA) 1.0 mg l−1, highlighting clonal lines L-250, L-132, and L-62. Because of high rates of vitrification and phenolization in the initial stage, clonal lines L-24, L-127, and L-142 were discarded from the study. Therefore, only seven clonal lines were included for evaluation in the multiplication stage. Once the microplants were obtained under laboratory condition in the culture medium, they were immediately transferred to a proliferation medium containing MS + BA 1.0 mg l−1. Only in three clonal lines (L-132, L-200, and L-250), a high multiplication rate (3.5 shoots/explant) was achieved with axillary bud formation. Of the seven clonal lines evaluated, clonal line L-250 achieved the highest rates in the variables shoot height (3.38 cm), number of leaves (13.4), and number of shoots/explant (4.4). In the rooting stage, clonal line L-250 obtained a significant improvement by transferring plantlets to direct acclimatization after 20 days of in vitro root induction in a medium containing MS + NAA 1.0 mg l−1. Similarly, in the acclimatization stage, the clonal line L-250 showed a significant result. Then, in the transplantation stage, the plants were transplanted to the field with 100% rooting; 30 days after the transplantation, the clonal line L-250 obtained 100% survival in the field than the control treatments (offspring from two locations were used – Mito and Alayo). As the rooting period is reduced by approximately 20 days by inducing direct root formation under greenhouse conditions, the micropropagation technique is optimized with the protocol used in this study.
M. Gonzales, L. Mattos
Peruvian Journal of Agronomy, Volume 2, pp 27-34; https://doi.org/10.21704/pja.v2i3.1230

Abstract:
This experiment was carried out at the province of Arequipa, to determine broccoli residual effects on the sclerotia population of Sclerotium cepivorum on the soil and determine the best fungicides and biocontrol agents on the biggest red onion production. In two field areas infected with Sclerotium cepivorum, soil samples were carried out to determine the number of sclerotia at the beginning and the end of the trial. One area received broccoli residues before treatment installation. The experiment had a laboratory and a field phase. The block design was used completely randomized (DBCA), using seven fungicide treatments (T1) control, Iprodione (T2), Thiabendazole (T3), Boscalid (T4), Carbendazim (T5), T harzianum (T6), Bacillus subtilis (T7). Both areas received the same treatments. The density of sclerotia in the soil was not significant between these areas. However, the addition of broccoli had lower percentages of incidence and severity and higher yields in all treatments. At the area that received broccoli, the Boscalid (T4) and the Iprodine (T2) fungicide were highlighted with 43.33 T/ha and 28.33 T/ha, respectively; the area without broccoli, the T4 with 38.33 T/ha and T2 with 25.56 T/ha. T5 (Carbendazim) had the lowest yield: 15.00 T/ha without broccoli and 19.58 T/ha with broccoli.
J. Mamani, L. Aragón
Peruvian Journal of Agronomy, Volume 2, pp 35-43; https://doi.org/10.21704/pja.v2i3.1231

Abstract:
In the rhizosphere, as the zone of biological activity, diversity of microorganisms can be found like bacteria of the genus Pseudomonas. They are characterized for controlling pathogens like Phytophthora cinnamomi, also to be promoters of growth. For this reason, in the present study, bacteria of the genus Pseudomonas were isolated from the avocado rhizosphere of the provinces of Casma, Huaral, and Lima. A total of six strains (R2, R5, R7, R10, S10 and S6) were selected for evaluating their biocontrol capacity against P. cinnamomi under in vitro and greenhouse conditions. In the in vitro test, strains S6 and S10 controlled 30.3 and 44 %, respectively. Under greenhouse conditions, Pseudomonas strains were inoculated on 4-month-old avocado cv. “Zutano” plants. Five months later, we evaluated the following variables: severity in roots, height increase, fresh root and leaf weight, and percentage of root and leaf dry matter. In greenhouse, the best strains in the control of P. cinnamomi were S6, R2, R7 and R10, controlling 55.2, 39.5, 33.7 and 31.0 %, respectively. In the increase of height, the strains S6, R2, R7 and R10 reached 11.4, 9.3, 7.6 and 5.1 cm, respectively. The percentage of dry matter of roots, strains S10, R10 and R7 obtained 29.6, 27.5 and 27.9 %, respectively. In this study, it was observed that although the application of Pseudomonas controls P. cinnamomi, it also induces the root and apical growth of avocado.
S. Prado, J. Castillo, S. Rodriguez
Peruvian Journal of Agronomy, Volume 2, pp 54-59; https://doi.org/10.21704/pja.v2i1.1198

Abstract:
The asparagus, a dioecious plant, usually includes plants of both sexes, though also hermaphrodite ones. The male inflorescences are frequented by adult Prodiplosis longifila, who lay such large amounts of eggs on them that its populations can reach millions of individuals over a lapse of 20 to 30 days, which is the plant regular flowering period. The field investigation took place in two locations: (i) the Irrigation Research Unit of the Universidad Nacional Agraria La Molina (UNALM) and (ii) properties of the Agricultural Society of Virú (SAVSA). The number of fallen flowers and larvae per bud after applying multiple treatments on asparagus plots of the two locations was counted to determine the best concentration and application time of various fertilizers to induce the highest percentage of flower fall to manage P. longifila populations. In the UNALM the fertilizer B Dose 2 generated the highest percentage of fallen flowers, 82.1 % ± 14.85 %, and the fertilizer C Dose 1 caused 74.94 % ± 13.78 %. In SAVSA the fertilizer B Dose 3 made a percentage of fallen flowers of 50.6 % ± 21.56 % and fertilizer B Dose 2, 49.85 % ± 16.28 %. The average number of P. longifila 2nd-stage larvae, evaluated on fifteen flowers and in three moments was 3.9 larvae. Foliar fertilizers applications affected both male and female flowers almost equally in all treatments, percentage-wise. Foliar fertilizers promote asparagus flowers falling, consequently contribute to a significative reduction of P. longifila populations, due to a larvae exposition to rapid desiccation under the sun.
M. Santistevan, R. Borjas, L. Alvarado, V. Anzules, V. Castro, A. Julca
Peruvian Journal of Agronomy, Volume 2, pp 44-53; https://doi.org/10.21704/pja.v2i3.1210

Abstract:
Surveys were applied to a sample of 83 lemon producers from this province, with structured questions about economic, ecological and socio-cultural dimensions. The sustainability was determined with techniques of multicriteria analysis to calculate the Economic Indicator (IK), Ecological Indicator (IE) and Socio-Cultural Indicator (ISC), to estimate the General Sustainability Indicator (IS Gen) of each farm. The 25.3% of the farms had an IK> 2; 60.24% an IE> 2 and 55.4% an ISC> 2. The 74.7% of the farms had an IS Gen <2, which indicates that the farms are not sustainable.
J. Maraví, O. Buendía, L. Alvarado, R. Borjas, V. Castro, A. Julca
Peruvian Journal of Agronomy, Volume 2, pp 6-13; https://doi.org/10.21704/pja.v2i2.1200

Abstract:
The objective of this study was to characterize banana farms in the Cuyani Microbasin in the district of Pichanaki, Chanchamayo province (Junín, Peru). We worked with a producer organization that has 400 partners, of which a sample was taken (n = 80) using the proportions method. It was found that the banana farms are very diverse, the person in charge is mostly a man, but there is an interesting percentage of the female gender in the administration of the farms. In general, producers have a basic educational level. The production system is traditional, the banana is grown alone or associated with other crops, such as coffee. Most producers consider that pests and diseases are the main factors limiting production, since they reduce yields and increase production costs. The farms were classified in five groups, the most important of which was 45% of the farms whose owner is a male, between 44 and 56 years old, with secondary education, who lives on the same farm. They do not have a property title, the house does not have basic services, and they have poultry and guinea pigs. They have 2 to 3 hectares of banana (cultivars: Island and Palillo, 600 to 1000 plants/ha). Its production costs are between 2000 and 3600 soles and a yield of 6.5 to 7.5 t/ha. The cultivar Isla is the most common but also the cultivars Palillo, Morado and Biscocho are planted.
Y. Callohuari, C. Vergara, J. Jiménez
Peruvian Journal of Agronomy, Volume 2, pp 27-33; https://doi.org/10.21704/pja.v2i2.1199

Abstract:
This survey aimed to determine the insect pests associated with Andean lupin (Lupinus mutabilis Sweet) and its parasitoids, under Peruvian central coast conditions. Sampling was made every seven days with the following methods: linear meter evaluations, plant organ evaluations, pitfall traps, and beating trays. Infested plant organs were taken to the laboratory for adult insect recovery (phytophagous or parasitoids). Pitfall traps and beating tray samples were also processed and stored. During the survey, 14,051 individuals belonging to 11 orders and 91 families were recorded. Insects that infested Andean lupin were Melanagromyza lini Spencer (stem borer), Liriomyza huidobrensis (Blanchard) (leafminer), Crocidosema aporema (Walsingham) (budborer), Grammopsoides tenuicornis (Casey) (stem borer) and Frankliniella occidentalis (Pergande) (bud and flower thrips). Diglyphus websteri (Crawford), D. begini (Ashmead), Chrysocharis flacilla (Walker), C. caribea Boucek, Chrysocharis sp. and Halticoptera arduine (Walker) were recorded as parasitoids of L. huidobrensis, whereas Carcelia sp. was recorded for C. aporema.
M. Huarhua, J. Flores, R. Acuña, W. Apaza
Peruvian Journal of Agronomy, Volume 2, pp 14-21; https://doi.org/10.21704/pja.v2i2.1202

Abstract:
The Blueberry production in Peru has had rapid growth in the last five years, from having no area of more than 3050 hectares at present. As a result of this increase, many pathologic plant problems have appeared among them Phytophthora sp. causing plants with symptoms of wilt, reddish of lower leaves, regressive death, rotting of roots and crown of different production areas of Peru. However, there is no identification reported in Peru. Therefore, this study was conducted in the Plant Pathology Clinic of the Universidad Nacional Agraria La Molina with the objective of to identify the species of Phytophthora causing Crown and root rot isolated from blueberry in Peru. Four isolates from the blueberry´s field were identified by morphological, molecular and pathogenically features. All the isolates formed corralled-type colonies with hyphal swelling on PDA and V-8 agar and produced obpyriform or ellipsoidal sporangia and globes chlamydospores. The internal transcribed spacer (ITS) of rDNA was amplified and sequenced with primer ITS1/ITS4 to confirm the identification, All the ITS nucleotide sequences from isolated obtained were submitted at GenBank of NCBI (Number Accession MH777152 to isolate AR-1, MH777151 to isolate AR-2, MH777150 to isolate AR-4, and MH777149 to isolate AR-3). Each one of the sequences showed 100% of homology with sequences of reference of P. cinnamomi in GenBank. Pathogenicity tests showed symptoms of redness and yellowing and root and Crown rot on Blueberry cv. Biloxi after 30 days of inoculation. Finally, concluded that P. cinnamomi is the species causing Crown and root rot in Blueberry in Peru. To our knowledge, this is the first report of P. cinnamomi on blueberry in Peru.
, A. Chaudhary, D. Pokhrel
Peruvian Journal of Agronomy, Volume 2, pp 22-26; https://doi.org/10.21704/pja.v2i2.1201

Abstract:
The rate, time and method of nitrogen (N) fertilizer application are strongly related to growth, development, and yield of the crop. This study principally focuses on the role of the nitrogen in growth, development, and production of the maize, emphasizing time and methods of fertilizer application and their suitable rates. The review shows that crop yield increases up to certain limit and declines if applied in an excess amount of nitrogen. Nitrogen affects various physiological and biochemical processes in plant cells that ultimately affect the growth and development of the plant. Nitrogen response by maize differs due to growth stages, environment and genotype of maize. Hybrid and improved maize varieties are more nitrogen-responsive than local varieties of maize. Proper nitrogen applications as basal doses at planting stage, split doses at critical growth stages namely knee high, and flowering stages are necessary for higher grain yield. This review serves as a useful tool to maize researchers and growers for making the right decision on nitrogen application on maize.
M. F. Pommpelli, J. M. Figueirôa, Flavio Lozano Isla
Peruvian Journal of Agronomy, Volume 2, pp 1-5; https://doi.org/10.21704/pja.v2i2.1133

Abstract:
We aimed to propose a reliable and accurate model using non-destructive measurements of leaf length (L) and/or width (W) for estimating leaf area (LA) of Surinam cherry (Eugenia uniflora L.). For model construction, 560 leaves were randomly sampled from different levels of the tree canopies and encompassed the full spectrum of measurable leaf sizes. Power models better fit E. uniflora leaf area than linear models; but, among of then, the best fit were made when product of the L and W (LW) were used. To validate these models, independent data set of 156 leaves were used. Thus, we developed a single power model (Yi = β0 xβ1) [LA = 0.685 (LW)0.989; standard errors: β0 = 0.014, β1 = 0.005; R2 a = 0.997] with high precision and accuracy, random dispersal pattern of residuals and unbiased. A simpler linear model [LA = 0.094 + (LW * 0.655); standard errors: β0 = 0.025, β 1 = 0.001; R2 a = 0.998] also described here to estimate leaf area of E. uniflora, which are as good as the first. The simplicity of the latter model may be relevant in field studies, as it does not demand high precision or expensive instruments.
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