The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodo...The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.展开更多
The caterpillar Spodopterafrugiperda is an important pest of several crops, due to the damage it causes and the difficulty of its control. The method of controlling these pests is through chemical insecticides, which ...The caterpillar Spodopterafrugiperda is an important pest of several crops, due to the damage it causes and the difficulty of its control. The method of controlling these pests is through chemical insecticides, which cause adverse effects to the biotic and abiotic environment. The selection of new insecticides that meet the requirements of efficacy, safety, selectivity and those are economically viable, is highlighting the study of mechanisms of plant defense. The present study aimed to verify the insecticide effect of 27 plants in three different types of plants extracts： aqueous, decoction and polypeptide on S. frugiperda. Three plants were chosen for performing sublethal effects bioassays： two plants with the highest corrected mortality （E. pulcherrima and R. simsii） and the other plant （Maytenus ilicifolia （espinheira santa）） with corrected mortality similar to control. In preliminaries bioassays, 25 plants showed corrected mortality less than 50%, according to Abbott＇s formula. R. simsii （azalea） and E. pulcherrima （billed parrot） showed 51% and 68% of corrected mortality, respectively. Only R. simsii aqueous and the three extracts of E. pulcherrima differ significantly from control （P 〈 0.05）. The aqueous extracts and decoction of R. simsii and polypeptide extract of E. pulcherrima reduced the larval period of S. frugiperda, different from control （P 〈 0.05）. The polypeptide extract of R. simsii reduced the pupal period of the target insect. The extracts obtained by decoction, aqueous and polypeptide of E. pulcherrima extracts and decoction of polypeptides and R. simsii affected the fertility and fecundity of S. frugiperda. For the other parameters, there is no significant difference when compared with the control. The results of this study suggest that the extracts obtained by decoction, aqueous and polypeptide of E. pulcherrima and R. simsii can be used to control S. frugiperda. However, the successful search, product starting from extracts of plants depends on the availability of plant and the entire assembly around the detection of bioactive products, in addition to the active ingredients of the chemical synthesis and elucidation of the target site insecticide molecule.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovari...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on sper...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.展开更多
文摘The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.
文摘The caterpillar Spodopterafrugiperda is an important pest of several crops, due to the damage it causes and the difficulty of its control. The method of controlling these pests is through chemical insecticides, which cause adverse effects to the biotic and abiotic environment. The selection of new insecticides that meet the requirements of efficacy, safety, selectivity and those are economically viable, is highlighting the study of mechanisms of plant defense. The present study aimed to verify the insecticide effect of 27 plants in three different types of plants extracts： aqueous, decoction and polypeptide on S. frugiperda. Three plants were chosen for performing sublethal effects bioassays： two plants with the highest corrected mortality （E. pulcherrima and R. simsii） and the other plant （Maytenus ilicifolia （espinheira santa）） with corrected mortality similar to control. In preliminaries bioassays, 25 plants showed corrected mortality less than 50%, according to Abbott＇s formula. R. simsii （azalea） and E. pulcherrima （billed parrot） showed 51% and 68% of corrected mortality, respectively. Only R. simsii aqueous and the three extracts of E. pulcherrima differ significantly from control （P 〈 0.05）. The aqueous extracts and decoction of R. simsii and polypeptide extract of E. pulcherrima reduced the larval period of S. frugiperda, different from control （P 〈 0.05）. The polypeptide extract of R. simsii reduced the pupal period of the target insect. The extracts obtained by decoction, aqueous and polypeptide of E. pulcherrima extracts and decoction of polypeptides and R. simsii affected the fertility and fecundity of S. frugiperda. For the other parameters, there is no significant difference when compared with the control. The results of this study suggest that the extracts obtained by decoction, aqueous and polypeptide of E. pulcherrima and R. simsii can be used to control S. frugiperda. However, the successful search, product starting from extracts of plants depends on the availability of plant and the entire assembly around the detection of bioactive products, in addition to the active ingredients of the chemical synthesis and elucidation of the target site insecticide molecule.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.
