The effectiveness of some insecticides in controlling the leaves weevil, Sitona spp., on root nodule damage and yield criteria in lentil fields in Daraa Governorate

Abstract

 This research was conducted to study the effect of some pesticides on some yield criteria of the local lentil variety (Horani) and their effectiveness in reducing the feeding capacity of lentil leaf weevil larvae (Sitona spp.) on root nodules within the field during the 2019 season in Daraa Governorate. Five pesticides were used in the recommended concentration for each one. One Pesticide for coat seeds: (active agent imidacloprid 70%), and four pesticides for treating foliage are in order:

 1- Pyrethroids group; (Alpha-cypermethrin 100 EC, 1 g/L).

 2- The spray pesticide (the active ingredient is Azdirachtin 1%).

 3- The spray pesticide (the active ingredient is thiacloprid + delta methrin). 4- The spray pesticide is the active ingredient is acetamprid, in addition to the control treated with water only. The counts of total and infected root

nodules were estimated, and some yield criteria were evaluated. Root nodules were severely damaged by larva feeding and the yield reduced in the control. The results showed that all treatments had a significant effect on reducing the larvae ability to feed on the root nodules the treated lentil plants, and on the number of total root nodules, in addition to reducing the percentage of infected root nodules, compared to the control, and there were significant differences (sig<0.05) among the tested pesticides in the effect on the count of total and infected root nodules, in addition to reducing the percentage of infected root nodules. The differences between the insecticide coat seeds and the other treatments were significant, as it was the most effective insecticide among the tested insecticides in increasing the number of root total nodules (16.33 ± 0.58 nodules) and reducing the feeding capacity of larvae. It has (7.67 ± 0.57 infected nodes) and the percentage of damage does not exceed (34.63% ± 3.18), which increases the infection tolerance. The results indicated that there were significant differences between the insecticides and the control in grain yield and the superiority of insecticides; Imidacloprid, alpha-cypermethrin, thiacloprid+, deltamethrin, and acetamprid over the pesticide Azdirachtin, without significant differences between them. Also, these pesticides outperformed the dry weight of 5 plants over the control, which did not differ significantly from the pesticide with the active ingredient Azdirachtin. However, the pesticide imidacloprid outperformed the control. Pesticides (Azdirachtin, acetamprid and alpha-cypermethrin) in the dry weight of five plants (1534.33 ± 40.07 g).

 The results indicated that there were no significant differences in the weight of 100 seeds among the insecticides, and The seed coat insecticide imidacloprid was the superior by its effect on the nodules and yield criteria. These results can contribute in improving integrated management programs for controlling the lentil leaf weevil Sitona spp.