CHEMICAL CONTROL OF WEEDS IN THE CULTIVATION OF PEANUT IN SANTA MARÍA DEL ORO, NAYARIT

Abstract

Weeds are a major limiting factor for peanut Arachis hipogaea L. production in Nayarit state, causing yield reductions of 92%, due to competition effects. The objective of this study was to determine the most effective treatment for the chemical control of weeds in the peanut crop. The experiment was planted in 1987, under rainfall conditions at San José de Mojarras, Santa María del Oro. A local variety with three grains, named "criolla", was used. The treatments were 10: five with preemergence herbicides, three with postemergence herbicides, one more was unweeding with a hoe and the control. A randomized complete block design was used, with four replications. All the herbicide treatments had a good control of weeds. The "Zacate Fresadilla" (Digitaria sp.) represented 60% of the weeds population, "Oreja de Ratón" (Ricardia scabra) 30%, "Aceitilla" (Bidens pilosa) 4% and "Gordolobo" (Helianthus annuus) 4%. Treatments with Oxifluorfen ( 1 l/ha), Oxitluorfen (0.5 l/ha) + Prometrina (1 kg/ha) and Fomesafen (2 l/ha) + Fluazifop-b (2 l/ha) caused from 15 to 30% of leaf phytotoxicity. This damage disappeared after 10 days. Treatments that caused no leaf damage were Alaclor (4 l/ha), Alaclor (2 l/ha) + Prometrina (1 kg/ha), and Metaclor (2 l/ha) + Prometrina ( 1 kg/ha). There were no signiticant differences between herbicide treatments, but their grain yield was higher than for the control.