Field and laboratory trials were conducted in Zagazig -Sharkia Governorate during 2007 and 2008 cotton seasons to evaluate the efficacy of emamectin benzoate (against cotton leafworm Spodoptera littoralis and pink bollworm Pectinophora gossypiella.Emamectin benzoate resulted in initial kill of 93.73 and 92.39 % reductions in the numbers of cotton leafworm Spodoptera littoralis, larvae, comparing with 98.22 and 95.93 % for the recommended IGR hexaflumuron (Consult) (while as the residual effect emamectin benzoate revealed to 83.69 and 82.35% reductions comparing with 95.07 and 93.93 % for the hexaflumuron, in 2007 and 2008 cotton seasons, respectively. The efficiency of emamectin benzoate in comparison with the recommended insecticide chlorpyriphos (Dursban) against cotton bollworm, pink bollworm, Pectinophora gossypiella, they resulted in 59.40 and 54.68% for emamectin benzoate, and 81.81 and 83.21% for chlorpyriphos as average seasonal reductions, during the two cotton seasons, respectively. Laboratory trials revealed that LC50 and LC 90 of emamectin benzoate were higher with cotton leafworm than pink bollworm, which were 2.783 and 1.656 ppm at LC 50 , while they were 29.096 and 11.193 ppm at LC 90 , respectively. The slope value of emamectin benzoate with cotton leafworm was 1.257 less than with pink bollworm which recorded 1.544.
The American cotton bollworm has been found to develop resistance against conventional insecticides. This study is an attempt to investigate the efficiency of emamectin benzoate and hexaflumuron, (biorational insecticides) on the eggs and the 1P st P instar larvae of Helicoverpa armigera (Hübner), under the laboratory conditions. The Hexaflumuron was ineffective insecticide when eggs were treated by field rate compared to emamectin benzoate and alpha cypermethrin that induced 100% mortality only when the recommended field rate was applied. The LCR 50 R values of emamectin benzoate, hexaflumuron and alpha cypermethrin on the 1P st P instar larvae were 0.0041, 2.442 and 11.362 ppm, respectively based on formulated materials. The results showed that emamectin benzoate, hexaflumuron were more effective insecticides compared to alpha cypermethrin. The mean larval duration periods were12.0, 13.7, 15.0 days when treated with the LC25 values of emamectin benzoate, hexaflumuron and alpha cypermethrin compared to 16.0 days recorded for control. It is obvious that the three tested insecticides induced highly significant increase in larval and pupal mortality. The longevity of adult moths attained 8.0, 9.0, 11.0 and 15.5 days for female; 8.0, 7.5, 11.0 and 14.0 days for male resulting from the 1P st P instar larvae treated with emamectin benzoate, hexaflumuron, alpha cypermethrin and control, respectively. Emamectin benzoate and hexaflumuron showed severe reduction in female moth fecundity, eggs fertility and hatchability. Therefore, the two compounds could be recommended to control this pest, especially they are environment friends.
he chemical compounds synthetized at the laboratory of faculty of science, Zagazig University. These compounds as follows: 3-amino-5-chloro-4-phenylazo-1H-pyrazole (A), 3amino-5-mercapto-4-phenylazo-1H-pyrazole (B), 3-amino-5hydrazino-4-phenylazo-1H-pyrazole (C) were tested on neonate larvae of spiny bollworm, Earias insulana (Boisd.) at constant conditions of 26± 1ºC. and 80 ± 5% R.H. Acute toxicity as well as their latent effects on the different stages of the survived larvae were studied. Corresponding to the acute toxicity, at LC50 level the toxicity effect of the three tested chemicals were in descending order as follows: A, C and B compounds. During larval stage, hydrazino phenyl pyrazole C caused significant prolongation in duration of the larval stage of spiny bollworm. All tested compounds revealed highly significant decrease in the weight of treated spiny bollworm larvae, pupation percentage and pupal duration compared to untreated larvae. In contrast, tested compounds A and B showed an increase on larval mortality percentage. On The other hand, adult emergence percentage was significantly affected by C compound, but sex ratio of emerged adults was not significantly affected compared to untreated larvae. A, B and C compounds shortened the male longevity compared with the untreated. The A compound shortened the female longevity compared with untreated. But C compound elongated the female longevity compared with the untreated check. All treatments decreased number of deposited eggs, which proved significant with A and B. Incubation periods were did not affected. Significantly A compound caused reduction in the hatchability of deposited eggs.
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