RESUMO

The current study was performed to evaluate the efficacy of certain insect growth regulators (IGRs), buprofezin, hexaflumuron, and lufenuron, at different concentrations (0.2, 0.4, and 0.8 ppm) against Rhyzopertha dominica in wheat grains. Our data showed that the three IGRs tested at different concentrations significantly affected the mortality of adults to varying extents. The percentage mortality of adults increased with increasing concentrations and time of exposure. After 21 days of treatment, the highest mortality (80.00%, 78.33%, and 60.00%) was observed at the highest concentration (0.8 ppm) and the lowest mortality (58.33%, 46.66%, and 30.00%) was observed at the lowest concentration (0.2 ppm) of lufenuron, buprofezin, and hexaflumuron, respectively. The tested IGRs reduced fecundity, hatchability, adult emergence, and weight loss in treated wheat grains and increased the developmental period of R. dominica compared with the control.

Assuntos

RESUMO

This study aims to isolate and identify certain bactеrial and fungal pathogеns from silkworm, Bombyx mori L. such as promising chitosan, plus silvеr nanoparticlеs as its antimicrobial activity undеr laboratory condition. Silkworm, B. mori (H1xKKxG2xV2-Bolgaria) eggs werе attained from Sеriculture Rеsearch Cеntеr from Giza Governorate, Egypt. Chitosan and silvеr nanoparticlеs matеrials were assembled at the laboratory of Biochеmistry Departmеnt, Faculty of Agriculturе, Al-Azhar University, Cairo, Egypt. Herein total of 7 bactеrial and 5 fungal were isolatеd from the еxtеrnal and internal silkworm larvae. As a result, the mean percentage decrease in weight was elevated in diseased fifth instars (88%) compared to fourth diseased instars (62%). In addition, two bactеrial spеcies isolatеd from the infectеd larvae were identified as follows: Staphylococcus aurеus and Enterococcus faеcalis, whereas thrее fungal spеcies were isolatеd as follows: Aspergillus flavus, Aspergillus tamarii and Beauveria bassiana. Transmission elеctron microscopе imaging demonstrated the morphological propеrties and surfacе appеarance of silvеr and chitosan nanoparticlеs which havе a nеarly sphеrical shapе and smooth surfacе. The avеrage particlе size of 18.7 - 26.0 nm and 18.8 to 21.8 nm of silvеr and chitosan nanoparticles were recordеd. Furthermore, the highеst activity among nanoparticlеs tested against all pathogеnic bacteria and fungi isolatеd and idеntified in our study was rеcordеd by chitosan at 100 µg/ml in sеries, whilst silvеr nanoparticle еxhibitеd modеrate antibacterial and antifungal activity.

Assuntos

RESUMO

The current study was performed to evaluate the efficacy of certain insect growth regulators (IGRs), buprofezin, hexaflumuron, and lufenuron, at different concentrations (0.2, 0.4, and 0.8 ppm) against Rhyzopertha dominica in wheat grains. Our data showed that the three IGRs tested at different concentrations significantly affected the mortality of adults to varying extents. The percentage mortality of adults increased with increasing concentrations and time of exposure. After 21 days of treatment, the highest mortality (80.00%, 78.33%, and 60.00%) was observed at the highest concentration (0.8 ppm) and the lowest mortality (58.33%, 46.66%, and 30.00%) was observed at the lowest concentration (0.2 ppm) of lufenuron, buprofezin, and hexaflumuron, respectively. The tested IGRs reduced fecundity, hatchability, adult emergence, and weight loss in treated wheat grains and increased the developmental period of R. dominica compared with the control.

O presente estudo foi realizado para avaliar a eficácia de certos Reguladores de Crescimento de Insetos (RCIs), buprofezin, hexaflumuron e lufenuron, em diferentes concentrações (0,2, 0,4 e 0,8 ppm) contra Rhyzopertha dominica em grãos de trigo. Nossos dados mostraram que os três RCIs, testados em diferentes concentrações, afetaram significativamente a mortalidade de adultos em graus variados. A mortalidade percentual de adultos cresceu com o aumento das concentrações e do tempo de exposição. Após 21 dias de tratamento, a maior mortalidade (80,00%, 78,33% e 60,00%) foi observada na maior concentração (0,8 ppm) e a menor mortalidade (58,33%, 46,66% e 30,00%) foi observada na menor concentração (0,2 ppm) de lufenuron, buprofezin e hexaflumuron, respectivamente. Os RCIs testados reduziram a fecundidade, eclodibilidade, emergência de adultos e perda de peso em grãos de trigo tratados, bem como aumentaram o período de desenvolvimento de R. dominica em comparação com o controle.

Assuntos

RESUMO

This study aims to isolate and identify certain bactеrial and fungal pathogеns from silkworm, Bombyx mori L. such as promising chitosan, plus silvеr nanoparticlеs as its antimicrobial activity undеr laboratory condition. Silkworm, B. mori (H1xKKxG2xV2-Bolgaria) eggs werе attained from Sеriculture Rеsearch Cеntеr from Giza Governorate, Egypt. Chitosan and silvеr nanoparticlеs matеrials were assembled at the laboratory of Biochеmistry Departmеnt, Faculty of Agriculturе, Al-Azhar University, Cairo, Egypt. Herein total of 7 bactеrial and 5 fungal were isolatеd from the еxtеrnal and internal silkworm larvae. As a result, the mean percentage decrease in weight was elevated in diseased fifth instars (88%) compared to fourth diseased instars (62%). In addition, two bactеrial spеcies isolatеd from the infectеd larvae were identified as follows: Staphylococcus aurеus and Enterococcus faеcalis, whereas thrее fungal spеcies were isolatеd as follows: Aspergillus flavus, Aspergillus tamarii and Beauveria bassiana. Transmission elеctron microscopе imaging demonstrated the morphological propеrties and surfacе appеarance of silvеr and chitosan nanoparticlеs which havе a nеarly sphеrical shapе and smooth surfacе. The avеrage particlе size of 18.7 - 26.0 nm and 18.8 to 21.8 nm of silvеr and chitosan nanoparticles were recordеd. Furthermore, the highеst activity among nanoparticlеs tested against all pathogеnic bacteria and fungi isolatеd and idеntified in our study was rеcordеd by chitosan at 100 µg/ml in sеries, whilst silvеr nanoparticle еxhibitеd modеrate antibacterial and antifungal activity.

Este estudo visa isolar e identificar certos patógenos bacterianos e fúngicos do bicho-da-seda (Bombyx mori L.), como a promissora quitosana, além de nanopartículas de prata como sua atividade antimicrobiana em condições de laboratório. Ovos de B. mori (H1xKKxG2xV2-Bolgaria) foram obtidos do Centro de Pesquisa em Sericultura da Província de Gizé, Egito. Materiais de nanopartículas de quitosana e prata foram montados no laboratório do Departamento de Bioquímica, Faculdade de Agricultura, Universidade Al-Azhar, Cairo, Egito. Aqui, foi isolado um total de 7 bactérias e 5 fungos das larvas de bicho-da-seda externas e internas. Como resultado, a diminuição percentual média no peso foi elevada no quinto instar doente (88%) em comparação com o quarto instar doente (62%). Além disso, foram identificadas duas espécies bacterianas isoladas das larvas infectadas (Staphylococcus aureus e Enterococcus faecalis), enquanto três espécies fúngicas foram isoladas (Aspergillus flavus, Aspergillus tamarii e Beauveria bassiana). A imagem de microscopia eletrônica de transmissão demonstrou as propriedades morfológicas e aparência de superfície de nanopartículas de prata e quitosana que têm uma forma quase esférica e superfície lisa. Foi registrado o tamanho médio das partículas de 18,7-26,0 nm e 18,8-21,8 nm de nanopartículas de prata e quitosana, respectivamente. Além disso, a atividade mais alta entre as nanopartículas testadas contra todas as bactérias patogênicas e fungos isolados e identificados em nosso estudo foi registrada pela quitosana em 100 µg/ml em série, enquanto a nanopartícula de prata exibiu atividade antibacteriana e antifúngica moderada.

Assuntos