Infestação de plantas daninhas e desenvolvimento da cultura do milho em consorciação com variedades de mandioca

Abstract

Intercropping practice maybe used to manage weeds in agricultural systems. This work had the objective of evaluating the effects of cassava intercropping on corn crop development and weed infestation underfíeld and laboratory condrtions. The experiment was established in Lavras, MG, Brazilin 2002/2003,usingeightcassavavarieties(UFLAE,UFLAG, UFLAH,UFLA J, IAC 12, IAC 13, IAC 14, IAC 15) planted in the same area of corn, Dow 8420 cultivar,infestedwithBidenspilosa,Cynodondactylon,Amaranthusviridis,and Cenchrusechinatus. UFLA G,UFLAJ, IAC 12, 13, and IAC 15 reduced corn Plant height up to10%ascomparedto control (corn mono crop).UFLAG, UFLA J, IAC 13, and IAC 15decreasedcomgrainyield(up to 26%)and Number of ears(up to21%).A H cassava varieties tested, except for UFLA J, decreased weed infestation up to11%.Inlaboratory, aqueous extracts of nine cassava varieties, eight mentioned before, plus "Fibra", at 3, 6, and 9% concentrations were applied on lettuce seeds in Petridishes. Genmnation rate index(GRI) and lettuce root length decreased as cassava leaf aqueous extracts increased up to 9%. IAC 12, IAC 14, UFLA E, and UFLA H reduced lettuce root growth up to 33%.