Evaluation of the effectiveness of chemical control agents against Bemisia tabaci (Genn.) on cucumber plants

Resumo

A field trial conducted in Al-Alam, Salah Al-Din (Iraq) evaluated Sivanto Prime (flupyradifurone), azadirachtin, and potassium silicate, applied alone or in combination, against the whitefly Bemisia tabaci on cucumber. The three-way mixture T9 (Sivanto Prime + potassium silicate + azadirachtin) was the most reliable option across sampling dates. Adult densities declined to 0.05 insects in⁻² by 28 days after spraying, with corrected mortalities of 98.49% versus the water control and 95.50% versus acetamiprid. For nymphs, the mixture recorded 4.49 nymphs in⁻² at 14 days, with corrected efficiencies of 69.47% and 43.80%, respectively. Sivanto Prime alone produced the fastest early knockdown in nymph counts (6.31 and 5.98 nymphs in⁻² at 1 and 3 days), giving corrected mortalities of 47.81–48.70% (vs. water) and 46.40–48.08% (vs. acetamiprid), and it achieved 97.48% corrected mortality for adults by day 28. Azadirachtin performed weakest on nymphs (36.77% corrected) and reached 88.80% for adults at 28 days. Suppression translated into better crop performance: the three-way mixture raised yield to 1466.11–1489.44 g plant⁻¹ compared with 827.8–851.6 g plant⁻¹ in the two controls, and increased leaf chlorophyll to 12.22 SPAD units versus 7.16 with water. Overall, combining distinct modes of action delivered more durable control than single products and improved both physiological and yield traits. The findings suggest that the T9 mixture (30 mL/100 L (Sivanto), 50 mL/100 L (potassium silicate), 125 mL/100 L (azadirachtin) should be used in the integrated pest management of cucumber. Since these results are from a single location and season, further studies on multi-location, multi-season validation and economic evaluation should be conducted.