Effects of piperonyl butoxide on Bemisia tabaci Genn. (Homoptera : Aleyrodidae): mortality, development, parasitism and predation in Israeli cotton fields

In field trials in Israel, piperonyl butoxide (PB) alone, at concentrations of 2000 and 5000 ppm exerted good control over nymphal Bemisia tabaci popu lations on cotton. Weekly doses of these concentrations exerted greater con trol than a recommended oil and were as effective as the standard single ap plication of buprofezin. Cypermethrin caused marked resurgence within the p lots, probably as a consequence of its detrimental effects on natural enemi es. Neither PB, buprofezin nor the oil reduced the incidence of natural ene mies. Treatment with 2000 or 5000 ppm PB resulted in a shift in age structu re toward a greater proportion of young instars than in other treatments. T here was some evidence that these effects facilitated a greater level of pa rasitism in PB-treated plots. (C) 1998 Elsevier Science Ltd. All rights res erved.