Effect of a New Phenoxy Juvenile Hormone Analog on California Red Scale (Homoptera: Diaspididae), Florida Wax Scale (Homoptera: Coccidae) and the Ectoparasite Aphytis holoxanthus DeBache (Hymenoptera: Aphelinidae)

Abstract

The toxicity of the juvenile hormone analog (JHA) 2-[1-methyl-2-(4-phenoxyphenoxy) ethoxy] pyridine (MPEP), was evaluated on California red scale (CRS), Aonidiella aurantii (Maskell); Florida wax scale (FWS), Ceroplastes floridensis Comstock; and the ectoparasite Aphytis holoxanthus DeBach. Treatment with 25 ppm inhibited the development of first- and 3-d-old second-instar CRS nymphs. The development of older second-instar CRS female nymphs was not arrested by a rate of 600 ppm, but the resulting females failed to reproduce following a 100 ppm application. A. aurantii females were not affected by the JHA treatment. When exposed to 50 ppm of MPEP, the three FWS nymphal stages ceased growing or failed to oviposit as adults. Treatment with 100 and 200 ppm resulted in 68.7 and 97.5% mortality of 3- to 10-d-old FWS females, respectively. Surviving young females ceased growing but began oviposition as morphologically immature scales; the number of eggs per female scale was significantly reduced and egg sterility was induced by the JHA treatment. Oviposition and egg viability of mature C. floridensis female scales were not affected by MPEP application. JHA treatment had no adverse effect on larval and pupal development of A. holoxanthus or on successful adult emergence and female fecundity.