Populations of the whitefly, Bemisia tabaci collected from the Americas and the Caribbean Basin were examined for non-specific esterases and for the ability to induce characteristic phytotoxic disorders in key assay species as a means of investigating biogeographic diversity. Esterase markers were used to detect polymorphisms among regional B. tabaci populations and to establish the present distribution of B. tabaci biotypes in the region. The A biotype occurred only in contiguous locales in northern Mexico and the southwestern US, while the B biotype was present throughout much of the Caribbean Basin and the US, and in Brazil. Distinct C and D type esterase markers were observed for Costa Rican and Nicaraguan B. tabaci populations, respectively. The 0 or null type population was collected only from Jatropha gossypifolia (L.) in Puerto Rico. Laboratory colonies of the A and the B biotypes were almost equally sensitive to an organophosphate, profenofos. The B biotype was more resistant to a pyrethroid, permethrin, suggesting the existence of a biotype of fi. tabaci, with a history of exposure to pesticides with a pyrethroid-based chemistry. In mating studies involving reciprocal crosses between the A and the B biotypes, very few F, female progeny were produced, indicating either minimal or non-existent reproductive compatibility between these haplo-diploid B. tabaci populations, presently considered to be the same species. Evidence is presented for the recent and widespread introduction, and subsequent spread of the B biotype throughout the US, the Caribbean Basin, and other proximal locations.

Twenty-one varieties of bambarra cultivated in Nigeria were compared with respect to their susceptibility to Callosobruchus subinnotatus (Pic.). The bruchids developed fastest on varieties TVSU155 and TVSU 702. Development from the middle of oviposition to the emergence of the first filial adults lasted 32.8 and 32.0 days, respectively. Development was slowest on TVSU 1033, lasting 42.6 days. The highest number of first filia (F1) adults emerged from varieties TVSU 11, TVSU 702 and TVSU 1231, while the lowest number emerged from TVSU 688. Susceptibility indices calculated for the varieties showed that TVSU 702 was the most susceptible variety, while TVSU 346 and TVSU 1033 were the least susceptible varieties. Losses associated with varietal infestation, assessed in terms of weight of bambarra consumed by the bruchids were high for highly susceptible varieties and low for the least susceptible ones.

Investigations on the biology of Cinara cupressi, a voracious aphid of cypress trees in Kenya, showed that the aphid produced four nymphal instars within a fortnight under laboratory conditions of 22°C and 89% r.h. Reproduction was two nymphs per female adult per day for 12 days of reproduction. Nymphal multiplication was brisk, but was drastically countered by mortality which was highest in the first, third and fourth instars. This led to a mere nymphal survival of 11.0% at most under laboratory conditions.

Crude ethanol extracts (CE) of leaves of 60 plant species belonging to 32 families and 52 genera were bioassayed for toxicity to adult Tribolium confusum by spraying a 10% (w/v) concentrate under a Potter's tower. CE of eight plants had none and three had some bioactivity; 36 CE killed from 13 to 40% of the beetles. Thirteen plant extracts inflicted between 53 and 100% mortality in the following order: Azadirachta indica (53%) < Eupatorium odorantum = Gliricida sepium = Mimosa pudica (60%) < Annona reticulata = Hibiscus rosa sinensis (67%) < Cycloptis semicordata < Artocarpus altilis < Capsicum annum (90–97%) < Bontia daphnoides = Cuscuta americana = Dioscorea polygonoides = Nkotina tabacum (100%).

The diel activity patter n of Glossina austeni was studied on the south coast of Kenya, and in the laboratory. In the field, flies were sampled hourly by continuous catch from a standing vehicle, or by traps. In the laboratory, observations were made of the flies' take-off-responses to host odour at various times of the diel cycle, in a flight chamber. The results showed that G. austeni is day-active with some activity throughut the daylight hours, but with significant peaks occurring at 09.00–10.00h and between 14.00 and 17.00h, i.e. a roughly V-shaped pattern.

Diapausing pupae of tasar silkworm, Antheraea mylitta Drury were injected with ox pancreas insulin (40 I.U. per ml) on day 150 to observe the effect of this vertebrate hormone on diapause physiology. Insulin at the dose of 5 μl (0.2 I.U.) per pupa exhibited its positive impact by enhancing the incidence of male and female moth eclosion, female moth weight, egg production (laid + unlaid), and fecundity and shortening of time taken for emergence in both sexes. But, 10 μl (0.4 I.U.) dose of insulin increased only the female eclosion and reduced the time taken for emergence in each sex when compared to that of control. Administration of higher dose of insulin (10 μ1 per pupa) decreased the egg production and fecundity. No significant changes were observed in hatchability and incubation phenomena of eggs laid by the treated females. Further, both the doses of insulin were able to bring about the morphometric changes of testis and ovary by altering their shape and size during pupal diapause. Thus, it reveals from the preliminary findings that vertebrate insulin induces diapause physiology of A. mylitta.