February 11, 2016

White Flies becoming a bigger Concern for Cotton Farmers in Brazil

Farmers always have to worry about things that might impact their crops such as weather and pests and now cotton farmers in Mato Grosso have added a new pest to their list of worries - white flies. Recently, the Brazilian Ministry of Agriculture added white flies to the list of significant cotton pests that already includes the boll weevil and Asian rust. White flies came to the forefront a few years ago as a significant pest for soybeans in Brazil and now it is becoming a significant pest for cotton as well.

In high numbers, the insect can impede the development of small cotton plants, they can transmit virus to the cotton plant, and they can contaminate the cotton fibers by introducing a fungus into the bolls. Farmers in Mato Grosso started planting their safrinha cotton last month and it has been reported by Global Rural that some farmers have already sprayed two or three times in an effort to control the insect in their newly planted cotton.

The insect populations seem to be especially high this year due to the favorable hot and humid weather that has engulfed the area over the past month and a half. Most of the cotton produced in Mato Grosso is now grown as a safrinha crop which is planted immediately after the soybeans are harvested. White flies are a major insect pest attacking soybeans and the problem is that many farmers stop their efforts to control the insect in soybeans as the crop approaches maturity. Researchers say this is a mistake because the insects can then move directly into the cotton crop as soon as the cotton plants emerge.

Controlling the insect is not easy or cheap. A general use insecticide might cost R$ 8 per hectare, whereas an insecticide specifically designated for white fly control might cost as much as R$ 80 or R$ 100 per hectare. Scientists are warning that the indiscriminate use of the cheaper general insecticides may actually spur the development of insecticide resistant white flies and it might be better to use the more expensive insecticides which provide better control.