Since the pesticides are considered as an essential component for crops production through controlling pests, they have shown a negative effect on crops and soil environment when used intensively. This experiment was ...Since the pesticides are considered as an essential component for crops production through controlling pests, they have shown a negative effect on crops and soil environment when used intensively. This experiment was conducted at Wadi Soba farm (Sharq Elneel) Khartoum, Sudan. It aimed to study the effect of Sevin residuals on carrot growth and Azotobacter spp. colonies growth. Carrot planted in late February 2013, Sevin pesticide (2.5 L/ha and 5 L/ha) was added to estimate plant height, dry weight, the number of plant leaves and the number of Azotobacter spp. colonies isolated from the carrot rhizosphere (0 - 15 cm). The obtained results showed that the Sevin recommended dose (2.5 L/ha) relatively had a positive effect on the plant height, dry weight, and the number of plant leaves. The average of plant height for recommended dose was 59.67 cm compared to control (53.67 cm) and high dose (27.33 cm). The average of plant dry weight obtained by the recommended dose was 503.33 g and for control was 476.67 g and for high dose was 166.7 g, it decreased 67% from control and recommended dose. The average of plant leaves number were 25.34, 13.66 and 21.33 for recommended dose, high dose and control respectively, the number of leaves increased about 16% by recommended dose and decreased 35% by high dose. The average of Azotobacter spp. colonies obtained by high dose of Sevin demonstrated a lower numbers which were 20 × 104, 5.67 × 106 and 0.33 × 108 compared with control (78.33 × 104, 44 × 106 and 15.33 × 108) and the recommended dose (64 × 104, 33 × 106 and 7 × 108). The high dose of Sevin had a negative effect on both carrot growth and Azotobacter spp. colonies growth.展开更多
We reported in this paper the results of our test of four insecticides used through cover spray for controlling the Asian longhorned beetle, Anoplophora glabripennis (Motsch.). The four insecticides were ASTRO (A. I. ...We reported in this paper the results of our test of four insecticides used through cover spray for controlling the Asian longhorned beetle, Anoplophora glabripennis (Motsch.). The four insecticides were ASTRO (A. I. 36 8% permethrin) by FMC Corp., AllPro DURSBAN 4E (A. I. 44 9% chlorpyrifos) by Sureco Inc., ORTHENE 75 S (A.I. 75% acephate) by VALENT USA Corp., and SEVINXLR PLUS (A. I. 44 1% carbaryl) by Rhone_Poulenc AG Co. (now part of Bayer CropScience). The insecticides were sprayed onto 1 5 years old poplar ( Populus sp . ) trees until insecticide run_off from twigs. Twigs were collected from treated trees once every 3 d until the 21 st day after insecticide application to feed caged adult beetles. Adult mortality was recorded once every day for 3 d. Leaf and twig samples of treated poplar were collected from each treatment 3, 6, 9, 20, 40 d after spray to determine the levels of insecticides in these parts of trees. Although all insecticides showed promise for short term efficacy (>95% 3 d mortality for adults feed on twigs collected 1 after application), permethrin (concentration 920 mg·kg -1 ) was the best among the 4 tested insecticides for longer residual activity with 3 d cumulative mortality>95% for adults feed on twigs collected within 15 days after application. Chlorpyrifos (2 245 mg·kg -1 ) was the least effective with 3 d cumulative mortality around 60% for adults feed on twigs collected within 6 d after application, while the mortality was around 90% and 75% for acephate (7 500 mg·kg -1 ) and carbaryl (17 640 mg·kg -1 ), respectively. However, high concentrations of acephate and carbaryl are not feasible for controlling adult beetles, especially in urban areas. In general, levels of insecticides were higher in leaves than in twigs for the 4 insecticide. Levels in leaf 3～9 d after application was 0 9～4 1 mg·kg -1 for permethrin,2 5～1 6 mg·kg -1 for chlorpyrifos,2 6～2 3 mg·kg -1 for acephate, and 35 2 ～49 6 mg·kg -1 for carbaryl. Residual levels 20～40 d after application were 2 8～1 9 mg·kg -1 ,1 4～1 2 mg·kg -1 , 1 9～1 4 mg·kg -1 and 40 9～39 7 mg·kg -1 for permethrin, chlorprrifos, acephate, and carbaryl. Based on the relationship of the mortality of adult beetles and residual levels of insecticides, mortality may reach 95% when the level of permethrin reaches 4 mg·kg -1 in leaf, 1 4 mg·kg -1 in twig. For acephate, a level of 2 5 mg·kg -1 in leaves or 2 1 mg·kg -1 in twigs will achieve 90% mortality of adult beetles.展开更多
文摘Since the pesticides are considered as an essential component for crops production through controlling pests, they have shown a negative effect on crops and soil environment when used intensively. This experiment was conducted at Wadi Soba farm (Sharq Elneel) Khartoum, Sudan. It aimed to study the effect of Sevin residuals on carrot growth and Azotobacter spp. colonies growth. Carrot planted in late February 2013, Sevin pesticide (2.5 L/ha and 5 L/ha) was added to estimate plant height, dry weight, the number of plant leaves and the number of Azotobacter spp. colonies isolated from the carrot rhizosphere (0 - 15 cm). The obtained results showed that the Sevin recommended dose (2.5 L/ha) relatively had a positive effect on the plant height, dry weight, and the number of plant leaves. The average of plant height for recommended dose was 59.67 cm compared to control (53.67 cm) and high dose (27.33 cm). The average of plant dry weight obtained by the recommended dose was 503.33 g and for control was 476.67 g and for high dose was 166.7 g, it decreased 67% from control and recommended dose. The average of plant leaves number were 25.34, 13.66 and 21.33 for recommended dose, high dose and control respectively, the number of leaves increased about 16% by recommended dose and decreased 35% by high dose. The average of Azotobacter spp. colonies obtained by high dose of Sevin demonstrated a lower numbers which were 20 × 104, 5.67 × 106 and 0.33 × 108 compared with control (78.33 × 104, 44 × 106 and 15.33 × 108) and the recommended dose (64 × 104, 33 × 106 and 7 × 108). The high dose of Sevin had a negative effect on both carrot growth and Azotobacter spp. colonies growth.
文摘We reported in this paper the results of our test of four insecticides used through cover spray for controlling the Asian longhorned beetle, Anoplophora glabripennis (Motsch.). The four insecticides were ASTRO (A. I. 36 8% permethrin) by FMC Corp., AllPro DURSBAN 4E (A. I. 44 9% chlorpyrifos) by Sureco Inc., ORTHENE 75 S (A.I. 75% acephate) by VALENT USA Corp., and SEVINXLR PLUS (A. I. 44 1% carbaryl) by Rhone_Poulenc AG Co. (now part of Bayer CropScience). The insecticides were sprayed onto 1 5 years old poplar ( Populus sp . ) trees until insecticide run_off from twigs. Twigs were collected from treated trees once every 3 d until the 21 st day after insecticide application to feed caged adult beetles. Adult mortality was recorded once every day for 3 d. Leaf and twig samples of treated poplar were collected from each treatment 3, 6, 9, 20, 40 d after spray to determine the levels of insecticides in these parts of trees. Although all insecticides showed promise for short term efficacy (>95% 3 d mortality for adults feed on twigs collected 1 after application), permethrin (concentration 920 mg·kg -1 ) was the best among the 4 tested insecticides for longer residual activity with 3 d cumulative mortality>95% for adults feed on twigs collected within 15 days after application. Chlorpyrifos (2 245 mg·kg -1 ) was the least effective with 3 d cumulative mortality around 60% for adults feed on twigs collected within 6 d after application, while the mortality was around 90% and 75% for acephate (7 500 mg·kg -1 ) and carbaryl (17 640 mg·kg -1 ), respectively. However, high concentrations of acephate and carbaryl are not feasible for controlling adult beetles, especially in urban areas. In general, levels of insecticides were higher in leaves than in twigs for the 4 insecticide. Levels in leaf 3～9 d after application was 0 9～4 1 mg·kg -1 for permethrin,2 5～1 6 mg·kg -1 for chlorpyrifos,2 6～2 3 mg·kg -1 for acephate, and 35 2 ～49 6 mg·kg -1 for carbaryl. Residual levels 20～40 d after application were 2 8～1 9 mg·kg -1 ,1 4～1 2 mg·kg -1 , 1 9～1 4 mg·kg -1 and 40 9～39 7 mg·kg -1 for permethrin, chlorprrifos, acephate, and carbaryl. Based on the relationship of the mortality of adult beetles and residual levels of insecticides, mortality may reach 95% when the level of permethrin reaches 4 mg·kg -1 in leaf, 1 4 mg·kg -1 in twig. For acephate, a level of 2 5 mg·kg -1 in leaves or 2 1 mg·kg -1 in twigs will achieve 90% mortality of adult beetles.
