Effects of atrazine residue on the growth and development of celosia ( Celosia argentea) under screenhouse conditions in Nigeria

Abstract

Atrazine is by far the most widely used herbicide for selective weed control in maize in southwestern Nigeria, following which vegetable crops may be sown to ‘catch’ remaining moisture under rainfed multiple cropping. This study investigated the effect of soil residual activity of atrazine at the recommended rate of 3.0 kg a.i. ha −1 on the growth and development of Celosia argentea under screenhouse conditions at intervals of 0, 3, 6, 9 and 12 weeks after treatment (WAT). Experimental findings indicated that atrazine significantly ( P<0.05) reduced total crop leaf area, fresh weight and dry weight of Celosia in all the herbicide treatments compared with the control. Similarly, it caused significant reductions in plant height during the first 6 weeks of plant growth relative to the control. Plant height was found to be linearly and positively correlated with time interval between atrazine application ( r=0.96). It was concluded that the maximum interval of 12 WAT examined in this study was insufficient for safe and effective cultivation of Celosia. Consequently, it should not be sown after maize crop in which atrazine has been used for weed control in order to avoid crop injury and yield reduction.