Document Type : Pest Management
Author
Assistant Professor, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization, AREEO, Tehran, Iran
Abstract
Insecticides can have unintended effects on non-target insects, such as natural enemies. This study evaluated the effects of some recommended insecticides for wheat pests on the seven-spot ladybird Coccinella septempunctata. The experiment was conducted in a completely randomized design with eleven treatments and three replications, under laboratory conditions at a temperature of 24 ± 2°C, relative humidity of 50-60%, and a photoperiod of 16:8 (light: dark). The treatments included the insecticides fenitrothion (0.5, 1, and 2 ml/L), deltamethrin (0.15, 0.3, and 0.7 ml/L), matrine (0.7, 1, 1.5, and 2 ml/L), and a control (water). Mortality rates in the pupal and adult stages of C. septempunctata were assessed, and the tested insecticides were classified based on the IOBC method. The results indicated that all three concentrations of deltamethrin and fenitrothion caused 100% adult mortality, whereas matrine caused no mortality in adults. For pupae, deltamethrin induced 100% mortality across all concentrations. Fenitrothion’s effects on pupae were significantly dose-dependent, with 100%, 82.2%, and 50% mortality observed at concentrations of 2, 1, and 0.5 ml/L, respectively. Increased concentrations of matrine also led to a significant rise in pupal mortality, with matrine at 2 ml/L causing over 81% mortality, placing it in the moderately harmful category. Based on the results, it is necessary to avoid the use of deltamethrin and fenitrothion during the peak population of C. septempunctata. Also, considering the increase in adverse effects of fenitrothion and matrine in higher concentrations, it is necessary to avoid increasing the consumption concentration of these compounds.
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