The organic cultivation of potato presents economical viability, however it faces problems in relation to the maintenance of sanity. This work was carried out to verify the effect of the silicon fertilization on the incidence of pest insects and in the productivity of potato in an organic system. Five treatments were tested, with four replications: 1- control; 2- fertilization applied via soil with silicic acid, in the dose corresponding to 0.35t.ha-1 3- fertilization applied via leaf with solution of silicic acid at 0.35%; 4- fertilization applied via soil with rock powder, in the dose corresponding to 2t.ha-1; 5- fertilization applied via leaf with rock powder solution at 2%. The treatments were applied 20 days after the plantation of the seed potato. The incidence of pest insects was monitored by means of the determination of the number of foliar lesions caused by Diabrotica speciosa (Germar) and the number of leaves mined by Liriomyza spp. The diameter and the height of the plants and the productivity were determined. Independently of the form of application and the source used, it was verified that the plants fertilized with silicon presented lower number of leaf injuries in relation to the control ones. However, it was not possible to verify the effect of the fertilization with silicon on the development and productivity of the culture.
Silicon; organic potato; insect plant resistance; pest control
