Growth and development of the cassava predatory mite Typhlodromalus aripo (Acari: Phytoseiidae) under different relative humidity regimes

Abstract

The effect of relative humidity regimes on the development and growth of the various development stages of the predacious mite Typhlodromalus aripo (Acari: Phytoseiidae) was studied in the laboratory at a constant temperature of 27 ± 2oC. The mite was raised on its natural diet of phytophagous cassava green mite, Mononychellus tanajoa Bondar, reared on cassava apices of young stems. Development was measured as the life history of the mite (the total duration from egg to egg) whereas growth was determined as the duration of days it took each immature stage to change into the next stage. Results of the study showed a negative correlation between the mite developmnentl peiod and relative humidity. Similarly, there was a negative relationship between the number of offspring (eggs) produced by individual female mites with respect to relative humidity regimes. These findings facilitate better understanding of the predatory mite population dynamics, in different environmental conditions and as a biological control agent of cassava pest M tanajoa.