Contributors
Authors
1
nsecticide Bioassay Department, Central Agricultural Pesticides Lab. (CAPL), Agriculture Research Center (ARC), 21616, Alexandria, Egypt
2
Plant Protection research Institute), Agriculture Research, Center (ARC), Alexandria, Egypt
3
Insecticide Bioassay Department, Central Agricultural Pesticides Lab. (CAPL), Agriculture Research Center (ARC), 21616, Alexandria, Egypt
4
Pesticide Chemistry and technology Department, Faculty of Agriculture, Alexandria University, Elshatby,Alexandria, Egypt
Abstract
Salicylic acid (SA), an inducer of systemic acquired resistance (SAR), was foliar applied (0.7 g L-1
) on two squash
varieties (Alexandrian, and Hollar) to investigate the integration between SAR and insecticides (thiamethoxam or
pymetrozine) on Bemisia tabaci management. Insecticides were applied at their recommended [FR] and half
recommended field [HFR] rates separately or in sequence with SA. The Filed experiments were carried out in September
and October during two subsequent successful seasons. In the first season, the sequential treatment SA&thiamethoxam
[FR] presented significantly higher initial reduction (24h after treatment) of B. tabaci adults on Alexandrian (88.5 %) and
Hollar (80.3%) varieties, compared with the other treatments. Conversely, the sequential treatment SA&pymterozine
[FR] on Hollar variety was the most effective against the immature stages (82.4%), While on Alexandrian variety the
highest reduction was obtained with the sequential treatment of SA&thiamethoxam [FR] (78.7%). Moreover, on both
varieties no significant differences were recorded between the sequential treatments of SA&thiamethoxam [HFR] or
SA&pymterozine [HFR] and each insecticide alone at the recommended rate. Furthermore, along 10 days of treatment a
significant high reduction of adults was recorded with the sequential treatment of SA&thiamethoxam [FR] on both
squash varieties. In the second season, similar trend was obtained, the highest reduction of adults was recorded with the
treatment of SA&thiamethoxam [FR] on both (Alexandrian 84.1%) and (Hollar 76.3%). As well, the sequential
treatments of SA&thiamethoxam [FR] and SA&pymterozine [FR] showed high reduction of adults along 10 days of
treatment. Regarding to the immature stages on both squash varieties, high average of initial reduction and reduction
along 10 days of treatments were recorded with all the sequential treatments compared with the individual treatments.
On Alexandrian, the significant highest reduction recorded with SA&pymterozine [FR] (86.2%), while on Hollar
recorded with SA&thiamethoxam [HFR] (60.9%). These results disclose the synergistic effect of SA that affected both
tested insecticides efficacy and persistence. Therefore, SA could be recommended in sequence with low rates of
insecticides for whiteflies management to reduce both rate and numbers of insecticides application which is in highly
demand.
Keywords
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