Investigations were carried out during 2018-2019 to study the effect of different geographical locations of North-Western Himalayas on biology and predation efficiency of Andrallus spinidens thriving in different crop ecosystems. Present analysis showed that there was no siginicant difference in predation efficiency and biology of A. spinidens from different altitudes of five different locations. Incubation period of predatory bugs varied from 6.41 ± 0.09 to 6.77 ± 0.29 days. Total nymphal period varied from 16.33 ± 0.67 to 18.67 ± 0.88 days. Adult longevity of unmated male and female ranged from 12 ± 1 to 13.66 ± 1.86 and 17.32 ± 0.88 to 19.33 ± 0.67 days, respectively. Adult longevity of mated male and female ranged from 4.66 ± 0.33 to 9 ± 0.58 and 11.67 ± 0.88 to 15 ± 0.58 days, respectively. Survival rate of female predatory bugs was observed longer than unmated male predatory bugs. In their first nymphal instar, predatory bug feed on plant sap, while the second instar nymph prey on its laboratory host, Spodoptera litura (Fabricius) (Lepidoptea: Noctuidae). The predation efficiency of the adult male varied from 57.54 ± 1.48 to 63.50 ± 1.92 per cent, whereas, in adult females it varied from 64.58 to 67.58 ± 0.73 per cent. By comparing the predation efficiency of adult A. spinidens from all five geographical locations it was observed that female predatory bugs are better predators than male predatory bugs. The study showed that no significant differences were observed in the biology or predatory efficiency of A. spinidens when present in different climatic and geographical locations. This suggested that the predator has adapted itself in different climatic conditions by maintaining its biological attributes which enhance the success rate of its potential as predator on commercial level.
The present investigation was carried out at Vegetable Research Centre, G. B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand during the 2013 and 2014 to evaluate the effectiveness of thiamethoxam, used as seed treatment against the sucking insects of tomato. The seed treatment with thiamethoxam protected tomato seedlings from aphids and thrips at the early season from the onset of seed planting. There was a fast initial effect against the pests then gradually decreased to reach a moderate effect. Data revealed that Thiamethoxam 70% WS @ 4.2 g a.i./kg of seed showed the significant pest reduction followed by Thiamethoxam 70% WS @ 3.85 g a.i./kg of seed. Highest yield was recorded by Thiamethoxam 70% WS @ 4.2 g a.i./kg of seed (28.25 t/ha) closely followed by Thiamethoxam 70% WS @ 3.85 g a.i./kg of seed (25.00 t/ha) as compared to untreated check (20.91t/ha). Percent increase in yield over control was highest (35.10%) in Thiamethoxam 70% WS @ 4.2 g a.i./kg of seed followed by Thiamethoxam 70% WS @ 3.85 g a.i./kg of seed (19.56%). The percent reductions of predators by Thiamethoxam, used as seed treatment, in both the seasons ranged from 1.65-2.58% which was very minimum. Hence, it was concluded that the seed treatment of tomato with Thiamethoxam 70% WS @ 4.20 g a.i/kg of seed reduced the early season insect-pests (aphid and thrips) and had very less effect of natural enemies population as compared to control and also increased the fruit yield significantly than other treatments.
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