Biological activities of spores and metabolites of some fungi isolated from dead larva of the spiny bollworms (SBW), Earias insulana (Boisd.) (Lepidoptera: Noctuidae), against the newly hatched larvae of the pest were carried out. Results showed that the fungi Metarhizium anisopliae, Acremonium sp., and Paecilomyces variotii had affected the newly hatched larvae of (SBW). Acremonium sp. was the most potent one as it had the highest newly hatched larval mortality percentage (65 and 58.33%) for its spore suspension and metabolites, respectively, while the lowest one (41%) was for P. variotii metabolites. Also, spore suspensions of the all fungal isolates had the highest larval mortality than fungal metabolites. Studying the enzymatic activity showed that Acremonium sp. produced protease enzyme on media containing gelatin, which caused the highest larval mortality (72.22%). These isolates showed different effects on all stages of the pest and decreased pupal weight, adult emergence percentages, deposited eggs, and hatchability percentages than the control. Identification of Acremonium sp. EZ1 was confirmed using 18 s rRNA and its accession number MN25101.
This study illustrates the effect of magnetic field (MF) on the toxicity of two insecticides, emamectin benzoate (Emazoate 2.15% EC) and spinosad (SpinTor 24% SC), and determines their adverse effects on the bollworm (Earias insulana) through various biological and biochemical assays. The investigation indicated that exposure to the insecticides in a MF of 180 mT resulted in stronger toxicity, with LC 50 values of 0.162, 1.211, and 1.770 ppm, respectively. In addition, the results showed that magnetized insecticides significantly increased in the duration of the total immature stages (larvae and/or pupae) 32.1 and 36.6 days, compared with 27.9 and 30.5 days, respectively, in the nonmagnetized insecticides, while untreated check was 21 days. Also, the magnetized insecticides reduced the percentage of adult emergence, and increased deformations in the larval and pupal stages. Furthermore, sex ratio was greatly affected by exposure to both insecticides in conjunction with the MF. Exposure of the larvae of E insulana to magnetized insecticides can bring about malfunction in some biochemical process and significantly decreased the invertase activity, and decreased the total protein and carbohydrates. In contrast, it can increase amylase compared with nonmagnetized insecticides and untreated controls. Results concluded that the two insecticides' MF affected growth, survival time, and biological and biochemical parameters of E. insulana. Bioelectromagnetics. 43:368-380, 2022.
aboratory tests have been conducted in Bollworms Research Department, Plant Protection Research Institute (Sharkia Branch). Field experiments have been conducted at Aga, Dakahlia governorate during 2018 cotton season to evaluate the efficiency of Lufenuron, Pyridalyl and Chlorpyrifos on larval population of H. armigera (Hüb.) as well as their effect on some biological and biochemical aspects in cotton fields. Results showed that, three insecticides had toxic effect on the newly hatched larvae of H. armigera. The highest toxic effect was recorded with Lufenuron (LC50 value was 0.95ppm) followed by Chlorpyrifos (LC50 value was 4.29 ppm) while the lowest was recorded with Pyridalyl (LC50 value was 6.02 ppm). The three pesticides caused increasing in the larval and pupal mortality and decreasing the larval and pupal duration also the larval and pupal weight, pupation, sex ratio percentages, adult longevity, oviposition periods, the number of laid eggs and hatchability percentages. Also the results showed changes in the activity of carbohydrates (amylase, trehalase, invertase), transaminase (ALT & AST) enzymes, acetylcholinestriase enzyme, total soluble protein (TSP) and total lipid (TL) on the American bollworm larvae treated with the three pesticides (Lufenuron, Pyridalyl and Chlorpyrifos). Field experiments showed that, the three insecticides caused population ' s reduction percentages of the H. armigera larvae in cotton fields. Chlorpyrifos caused the highest reduction reached (80.06%) while, Pyridalyl caused the lowest reduction reached (65.28%) as compared with control. Mean while population reduction rate resulted from used Lufenuron insecticide reach (70.07%).
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