Sudanese cotton and the whitefly: a case study of the emergence of a new primary pest

Evaluation of Peracid Activated Organophosphates in Studies of Insecticide Resistance Conferred by Insensitive Acetylcholinesterases

“…The mechanism of OP -and CB -resistance in B. tabaci from different regions of the world has been found to be insensitive AChE (Dittrich et al 1985(Dittrich et al , 1990Byrne & Devonshire 1993, 1997Byrne et al 1994;Anthony et al 1998;Byrne & Toscano 2002;Byrne et al 2003;Erdogan et al 2008). We have provided a quick and accurate method of determination of specific activity of the AChE of B. tabaci, which is a direct indication of the level of resistance to OPs and CBs.…”

Ecological Determinants of Bemisia tabaci Resistance to Insecticides

“…During this same period of time, no resistance problems were being reported with the whitefly currently referred to as biotype Q in southern Spain because the plastic-culture industry and intensive insecticide-based management now common there had not yet established. The roles have now reversed as biotype Q has become notorious for its high resistance while the situation in the Sudan is unknown due to a decline in pest management information that developed following the resistance crisis of the late 1970s (Dittrich et al 1985).…”

“…An institutional program of insecticide sprays on cotton contracted to the former Ciba-Geigy Corp led to massive outbreaks of B. tabaci during the 1970s over the entire Gezira scheme. While insecticide resistance was implicated (Dittrich et al 1985) in the loss of field efficacy, catastrophic reduction in natural enemy populations was also identified (Eveleens 1983) as a factor responsible for unchecked B. tabaci populations.…”

Management of Resistance to Novel Insecticides

“…Problems with evaluating some novel compounds against Bemisia tabaci illustrate this point well. Since most chemieals used to control B. tabaci in the past have exhibited rapid contact activity against adults, a residual bioassay exposing adults for a maximum of 72 h to leaf discs dipped in formulated insecticide has proved of broad applicability (CahilI et al 1995;Dittrich et al 1985). The advent of the insect growth regulators buprofezin and pyriproxyfen, neither of which inflict direct mortality on whitefly adults (Ishaaya et al 1988;Ishaaya and Horowitz 1992), has necessitated the exposure and monitoring of eggs or nymphs to disclose resistance to these agents (CahilI et al 1996a;Ishaaya 1992, 1994).…”