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The sweetpotato whitefly, Bemisia tabaci (Gennadius) is the vector of the cassava mosaic geminiviruses (CMGs) that cause cassava mosaic disease (CMD). Synergistic interactions between B. tabaci and CMGs have been hypothesized as a cause of whitefly "super-abundance," which has been a key factor behind the spread of the severe CMD pandemic through East and Central Africa. The current study investigated this hypothesis by conducting experiments with CMD-susceptible cassava varieties infected with different CMGs in both the north-western Lake Zone region (pandemic affected) and the eastern Coast Zone where CMD is less severe. Male and female pairs of B. tabaci were placed in clip cages for 48 h on plants of three cassava varieties at each of the two locations. There were significantly more eggs laid on CMG-infected than on CMG-free plants in the Lake Zone, whereas in Coast Zone, there were no significant differences. There were no significant differences in proportions, mortality, and development duration of immature stages of B. tabaci among virus states and cassava variety in the two locations. The overall number of eggs was significantly higher with longer development duration of the immature stages in the Lake than in the Coast Zone, whereas mortality was significantly higher in the Coast than in the Lake Zone. Based on these results, it is concluded that there was no net positive synergistic interaction between CMGs and B. tabaci for either lowland coastal or mid-altitude inland populations. Consequently, other factors seem more likely to be the cause of the "super-abundance," and require further investigation., (© The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The transition from ground to air in flying animals is often assisted by the legs pushing against the ground as the wings start to flap. Here, we show that when tiny whiteflies (Bemisia tabaci, body length ca. 1 mm) perform take-off jumps with closed wings, the abrupt push against the ground sends the insect into the air rotating forward in the sagittal (pitch) plane. However, in the air, B. tabaci can recover from this rotation remarkably fast (less than 11 ms), even before spreading its wings and flapping. The timing of body rotation in air, a simplified biomechanical model and take-off in insects with removed wings all suggest that the wings, resting backwards alongside the body, stabilize motion through air to prevent somersaulting. The increased aerodynamic force at the posterior tip of the body results in a pitching moment that stops body rotation. Wing deployment increases the pitching moment further, returning the body to a suitable angle for flight. This inherent stabilizing mechanism is made possible by the wing shape and size, in which half of the wing area is located behind the posterior tip of the abdomen., (© 2016. Published by The Company of Biologists Ltd.)

The tomato leafminer, Tuta absoluta (Meyrick), had established in Israel by 2010, attacking both open-field tomatoes and greenhouse crops.We searched for its natural enemies in open-field tomatoes, and tried to determine their potential for controlling this pest. We surveyed the local natural enemies in open tomato fields and measured their impact on pest populations in an unsprayed field. We assessed the suppressive ability of the dominant hemipteran predator, Nesidiocoris tenuis Reuter, against T. absoluta under controlled laboratory conditions and evaluated the impact of its augmentation on T. absoluta control in open-field tomatoes. We found five natural enemy species:the predator, N. tenuis, two braconids, and two eulophids. Predation accounted for 64.5±9.2% (mean ± SE) of T. absoluta larval mortality, whereas parasitism accounted for 20.96±7.5%. Together, they eliminated the pest population at tomato harvest time. Under controlled conditions, predation by N. tenuis rose from 58 to 72% with increased density of T. absoluta, suggesting positive density dependence. The reduction of T. absoluta (83%) by N. tenuis was higher than that of Bemisia tabaci (32%), suggesting a preference of N. tenuis for T. absoluta. Augmentation of N.tenuis was as effective as conventional treatment insecticide treatment, and plant damage was low and did not seem to affect yield. Results indicate that reduced pesticide use enables indigenous natural enemies, particularly N.tenuis, to successfully control T. absoluta and prevent crop damage in open-field tomatoes.

Whiteflies are small hemipterans numbering more than 1,550 described species, of which about 50 are agricultural pests. Adults are free-living, whereas late first to fourth instars are sessile on the plant. All known species of whitefly parasitoids belong to Hymenoptera; two genera, Encarsia and Eretmocerus, occur worldwide, and others are mostly specific to different continents. All parasitoid eggs are laid in-or in Eretmocerus, under-the host. They develop within whitefly nymphs and emerge from the fourth instar, and in Cales, from either the third or fourth instar. Parasitized hosts are recognized by conspecifics, but super- and hyperparasitism occur. Dispersal flights are influenced by gender and mating status, but no long-range attraction to whitefly presence on leaves is known. Studies on En. formosa have laid the foundation for behavioral studies and biological control in general. We review past and ongoing studies of whitefly parasitoids worldwide, updating available information on species diversity, biology, behavior, tritrophic interactions, and utilization in pest management.