Typhlodromalus aripode leon (acari: phytoseiidae) development and reproduction on major cassava pests at different temperatures and humidities: an indication of enhanced mite resilience

Abstract

Both prey type and abiotic conditions limit performance of phytoseiid predators. The exotic predatory mite, Typhlodromalus aripo developed and reproduced when maintained on eggs and active stages of the cassava green mite(CGM)Mononychellus progresivus at three different temperatures. At the highest temperature of 33°C and the lowest at 12 °C, mite survival was less than 15 % over a period of ten days with low fecundity. At 12 °C, immatures took longer to reach maturity, while at 33 °C high mortality (>80 %) occurred. The best performance was recorded at 27 °C and 75 % relative humidity. Typhlodromalus aripo was also able to feed, develop and reproduce on the crawlers’ stage of the whitefly, Bemisia tabaci and the nymphal stage of the mealybug, Phenacoccus manihoti, though a low survival rate (<10%) was observed for the stages of protonymph, deutonymph and adults. Normal life stage development and egg hatchability were recorded at 27 °C and 75 % RH. The egg stage exhibited high drought tolerance (70 % hatching at 40 % RH). Typhlodromalus aripo females consumed less than 3 crawlers and produced less than one egg/day when fed with B. tabaci and P. manihoti at 75 % RH. The study indicated that for successful utilization of T. aripo in the biological control of CGM, it would be important to introduce the predator at low prey density whether in absence or presence of alternative prey on cassava. In conclusion, results revealed T. aripo to have drought resilient survival attributes which enhances this phytoseiid as an effective biological control agent.