Controle de plantas daninhas no cultivo sequencial de milho e feijão intercalares a um seringal em formação

Abstract

One field experiment was established at the Experiment Station "El Nus" of CORPOICA in San Roque, Antioquia, Colômbia, to evaluate the efficacy of post emergence herbicide applications for weed control on corn and dry beans intercropped with rubber tree. The cultivars of corn, dry beans and rubber tree were ICA 305, ICA Citará and IAN 710,respectively.The experimental design was randomized block with four replications in a (2 x 3) + 3, factorial scheme, plus three additional treatments, being 2corn herbicides and 3dry beans herbicides, plus weeded and unwedded check sand free checks. The compounds and rates tested were:nicosulfuron50gha,'1 isoxaflutole 60gha"1 applied on com,anddiclofop700gha,"1 fenoxaprop 68gha'1andsethoxydim230gha"1 plus 1.5 Lha"1 of mineral oil on dry beans. Herbicide applications were performedwithaback-packC02pressurizedsprayer (40 pounds per square inch) equipedwithone 8002Teejetnozzledehvering250 Lha"1 of herbicide solution. The main weed species present in the experimental área included: Hyparrheniarufa, Imperata cilíndrica, Scleriapterota, Emiliasonchifolia, Stachytarphetaca yennensisand Crotontrinitatis. Nicosulfuroncaused 40.87% visible injury to complaints, at 30 days after application (dap), 18% plant dry weight reduction and 41.2% grain yield reduction. Nicosulfuron and isoxaflutole did not control grassy species. Diclofop, fenoxaprop and set hoxydimappliedon dry beans after nicosulfuron and isoxaflutole efficiently controlled grassy species, without visible injury symptoms and dry beans grain yield reductions. Diclofop applied after isoxaflutole and fenoxaprop after nicosulfuron, affected pods number per plant. The herbicides used on com and dry beans caused neither visual injure symptoms nor affected rubber tree growth.