MIXTURE OF HERBICIDES AND MOLIBDENIUM APPLIED IN POST-EMERGENCY IN COWPEA CROP

Abstract

Tank mixing between herbicides and foliar fertilizers can promote adverse effects on crops due to antagonism between products. Thus, the objective of this study was to evaluate the effects of the application of molybdenum (Mo) in a tank mixture with herbicides on cowpea crop yield and weed control. The randomized block design was adoted, with four replications in a 6x2 factorial scheme. The first factor consisted of the control with weeding and control without weeding and the application of the herbicides bentazon, imazethapyr and the mixtures bentazon + imazamox and bentazon + imazethapyr. The second factor by the absence and application of 80 g ha-1 Mo. Weed density and dry mass, phytointoxication, main stem length, stem diameter, chlorophyll a and b contents and cowpea yield components were evaluated. Mo application associated with bentazon, imazethapyr, bentazon + imazamox, bentazon + imazethapyr herbicides did not affect weed control efficiency and selectivity for BRS Guariba cowpea. Herbicide-induced phytointoxication was mild (<5%) at 7 days after treatment application (DAT), with symptoms disappearing at 14 DAT. Mo application increases chlorophyll a and b content at flowering, the length of the main stem and the number of pods per plant at harvest time. Weeds reduce cowpea grain yield, regardless of Mo application.