Resistência de cultivares de arroz ao gorgulho Sitophilus spp. (Coleoptera; Curculionidae)

Abstract

The aim of this work was to determinate which of the recommended varieties for the Piauí State would offer more resistance to the weevil attack when stored with husk.The experimental desinyn was completely randomized with 7 treatments and 6 replications. The varieties used were Metica-1, Cica-9, Cica-8 and Cica-4 (recommended for irrigated crop) ad IAC-47, IAC-164 and IAC-165 (recomrnended for upland crop) . A 200 g sample of each variety was infested with 10 adult insecta, which were removed 12 days later. In the foliowing 30 days the emergence of adulta was daily counted. Before infestation, a sample of 20 g was taken of each variety morder to verify the percentage of grama with husk damage.The results showed that the varieties Cica-8 and Cica-4 were the most resiatant, with an average emergence of 0,33 and 1,5 insects per can, resoectively. The variety Metica-1 was the most susceptible with an average 66,33 insecta emerged; the other varieties showed interrnediary resistance with emergence of 16 to 26 adulta. It was verified a high positivecorrelation (r = 0,9426) between husk damage and the number of emerged insects.Recebido em 23/5/90 'EMATER-PI -R. Joo Cabral,