Silicon and imidacloprid on plants colonized by Myzus persicae and on vegetative development of potato

The aphid Myzus persicae (Sulzer) is a key pest of potato crops, the yield of which depends on insecticides for its control. This research was carried out to verify the effect of silicon and imidacloprid on the colonization of potato plants by M. persicae and its possible positive coasequences on development parameters. Five treatments with seven replications were tested: 1- control treatment: 2- 1% silicic acid: 3-imidacloprid at the recommended dosage (252g ha(-1)): 4- 1% silicic acid and imidacloprid at half recommended dosage (126g ha(-1)) and 5- imidacloprid at half the recommended dosage (126g ha(-1)). Twenty days after planting. the plants were infested with ten adult aphids. After 20 days of infestation. the number of nymphs and of adult aphids: the height. the diameter, the number of leaves and the fresh and dried weights of the plants were evaluated. The plants treated with insecticides were not so colonized by the aphids and those with silicon presented lower infestation in relation to the control. In relation to the height, diameter and weights, there was no significant difference among the treatments. however the control presented the lowest number of leaves. Therefore, silicon reduced the colonization of potato by M. persicae and the use of half dosage of imidacloprid (126g ha(-1)) was equally efficient to prevent the colonization, making silicated fertilization one more strategy to be tested in the integrated management of potato plant pests.