Biology ofEutetranychus Banksi: Life Tables on ‘Marsh’ Grapefruit Leaves at Different Temperatures (Acari: Tetranychidae)

Abstract

Females of Eutetranychus banksi (McGregor) developed from egg to adult in 29.6, 17.2, 13.1, 11.6, 11.7 and 9.6 days compared to 27.7, 16.4, 12.0, 10.1, 10.8 and 8.5 days for males at 15, 20, 25, 28, 30 and 32°C. Developmental times were significantly different (P < 0.05) between the two sexes at each temperature. Mites were reared on whole leaf arenas of Citrus paradisi Macf. in environmental chambers illuminated 12:12 LD. The intrinsic rate of increase (r_m) was 0.066, 0.123, 0.179, 0.210, 0.224 and 0.190 at 15, 20, 25, 28, 30 and 32°C. Sex ratio was strongly biased toward females (< 80%) between 20 and 30°C and declined to 68% at 15°C and 61% at 32°C. The maximum net reproductive rate (R₀) was 31.26 at 28°C followed by 26.06 at 30°C and 25.29 at 25°C. Eutetranychus banksi appears to have a higher intrinsic rate of increase between 28-30°C compared to published data for Panonychus citri (McGregor).