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

Biology and morphometry studies of the cassava mealybug,Phenacoccus manihotiMatile-Ferrero(Hemiptera: Pseudococcidae), on cassava (Manihot esculentaCrantz) were carried out on the M4variety.P. manihotidamages cassava through direct feeding on sap and the injection of toxic saliva.Additionally, it concomitantly promotes sooty mold growth and development. Establishing a com-prehensive insect management strategy requires a fundamental understanding of the biology of pestspecies. In this experiment, cassava cuttings were planted in polybags within a polyhouse. After reach-ing the eight- to ten-leaf stage, the plants were inoculated with 20 eggs each and observed daily untilthey completed their life cycle. This observation process was carried out on 80 individual insects, eachrepresenting a replicate. The mean egg duration was 6.8 days, the durations of the first, second, andthird nymphal instars were 6.4, 4.6, and 5.3 days, respectively, and the duration of the adult stage was20.9 days. Similarly, the mean duration of pre-oviposition was 5.7 days, the duration of the ovipo-sition 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 (Ro)was 226.78 female/female, the mean generation time (T) was 33.07 days, the intrinsic (rm) and finite (lambda) ratesof increase were 0.164 and 1.178 female/female/day, respectively, and the doubling time was 4.22 days. A non-significant variation was observed in the morphometrics (length and width) within the same instar stages ofP. manihoti. This information is essential for gaining insights into population dynamics andformulating efficient management approaches forP. manihotiunder investigation.