Ecology And Control Of The Tomato Russet Mite Aculops Lycopersici (Tryon)

1. This paper reported the spatial distribution and the spatial pattern of Aculops lycopersici in tomato fields. The results indicate that the spatial distribution pattern of A. lycopersici is aggregative distribution in tomato fields, it is also aggretive distribution among various parts of the plant, but the aggretive extent is not equal, the aggretive intensity of the lower is higher than the upper and the middle. Aggretive causes analysed by λ-value, the results indicate that aggretive distribution is caused by insect habit and environmental factors together. The calculation for the theoretical sampling for different density of the mite by formula is: n = (t~2/D~2){(α+1)/m+β-1} of Iwao- Kuno, under some level of error, the theoretical sampling number should decrease as the average density of the mite increase.2. The effect of constant temperiture on the development biology of the tomato russetmite was conducted at 14℃, 17℃, 20℃, 23℃, 26℃, 29℃, 32℃ and 35℃. Afemaleadult was put into a rearing disc, only one egg was left, all others were removed. Therearing discs were then kept in an incubator (ZRX-258DF) under long-day conditions(L16:D8). There was a significant effect of rearing temperature on survival rate, the highestwas 89.86% at 23 ℃; developmental period was very short at high temperature. Within therange of the experiment temperature, developmental period decreased as temperatureincreased. Devolopment rates of Aculops lycopersici increased linearly as rearingtemperature increased, regression equation between the velocity of development andtemperature were in order: Yegg = 0.0228X - 0.2343, Ynymph = 0.0148X - 0.0935; adultlongevity decreased with increasing temperature reaching 20.4 days at 26℃. Thedevelopmental zero temperature for egg, nymph and the period from egg to adult were10.51℃, 9.02℃, 9.15℃, respectively. A total of 105.56degree-days above 9.15℃ wererequired to complete the development from egg to adult emergence. The reproductive ratewas highest at 26℃, and the female adult mite laid 44.3 eggs in postembryonic period. Thehighest intrinsic rate of natural increase at 26 ℃ was 0.2645 per day.3. The effect of relative humidity on the development, reproduction and population...