Evaluation of the repellent effects of four chemicals in the control of red-billed in rice in chókwè irrigation scheme

Red-billed (Quelea quelea) is one of the most damaging pests of rice in Mozambique. For its control, smallholder farmers rely on different frightening techniques to scare birds from their crops. Apart from providing a temporary relief, this method requires energy and it is time consuming making farmers, particularly woman and children spend more of their time scaring birds than doing other activities. Therefore, this study was conducted at Chókwè Research Station, in 2012, to evaluate the repellent effect of methiocarb, amonnium sulphate, cooper oxichloride and carbaryl at their recommended rates and reduced to 50%, in the reduction of panicle damage and yield loss caused by red-billed on ripening rice (Oryza sativa L. ‘ITA-312’). The experiment was set as a complete block design with four replications. Collected data included grain yield, number of shoots m-2, panicle number and damage, plant height, grain sterility and thousand grain weight. Methiocarb applied alone and combined with ammonium sulphate was the most effective chemical tested, with 8.14% and 10.06% of panicle damage and a yield loss of 21.37% and 27.76%, respectively. The lower repellent effect was observed with carbaryl and amonium sulphate with panicle damage above 66.92% and yield losses of 44.91% and 84.04%, respectively. The number of shoots m-2, panicle number, plant height, grain sterility and thousand grain weight was not different in all products tested. This study showed that methiocarb can be used as an alternate method to the traditionally used by smallholder farmers of frightening birds.