Sources of silicon in the induction of resistance for pest insects and in the development of potato enhancement

Abstract

The exclusive use of synthetic insecticides for insect pest control causes several side effects. The plant resistence induction is a potential strategy to prevent the insect damage in the culture. The objectives of this work, was to evaluate the effects of silicon sources in the induction of resistance to the main pest insects and in the development and productivity of organic potato crops. Four treatments were tried: 1 fertilization with agro-silicon corresponding to 8 t/ha; 2 - fertilization applied by spray with solution of silicic acid at 0,8%; 3 fertilization applied by spray with solution of eucalyptus ash at 5% and 4 - Control. The incidence of pest insects was monitored 20, 40 and 60 days after the emergency of plants, being counted the number of aphid, leaves injuries caused by Diabrotica spp. and the number of mined leaves by Liriomyzas pp. The diameter, height and the productivity was determined, as the content of tannins and lignin present in the plants. The silicic acid acted as inductor of the tannin synthesis in the plant and the treatments ash and agro-silicon acted as promoter of the vegetative development of the plants.