Biology and morphometrics of cassava mealybug, Phenacoccus manihoti Matile-Ferrero, 1977 (Hemiptera: Pseudococcidae)

Abstract Biology and morphometry studies of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), on cassava ( Manihot esculenta Crantz) were carried out on the M4 variety. P. manihoti damages cassava through direct feeding on sap and the injection of toxic saliva. Additionally, it concomitantly promotes sooty mold growth and development. Establishing a comprehensive insect management strategy requires a fundamental understanding of the biology of pest species. In this experiment, cassava cuttings were planted in polybags within a polyhouse. After reaching the eight- to ten-leaf stage, the plants were inoculated with 20 eggs each and observed daily until they completed their life cycle. This observation process was carried out on 80 individual insects, each representing a replicate. The mean egg duration was 6.8 days, the durations of the first, second, and third nymphal instars were 6.4, 4.6, and 5.3 days, respectively, and the duration of the adult stage was 20.9 days. Similarly, the mean duration of pre-oviposition was 5.7 days, the duration of the oviposition period was 11.3 days, and the duration of post-oviposition was 3.8 days. Overall, on average, the life cycle took 44.2 days, and a single female could lay 259 eggs. The net reproductive rate ( ) was 226.78 ♀/♀, the mean generation time ( T ) was 33.07 days, the intrinsic (rm) and finite ( λ ) rates of increase were 0.164 and 1.178 ♀/♀/day, respectively, and the doubling time was 4.22 days. A nonsignificant variation was observed in the morphometrics (length and width) within the same instar stages of P. manihoti . This information is essential for gaining insights into population dynamics and formulating efficient management approaches for P. manihoti under investigation.