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Whitefly resistant to insecticides found in Mato Grosso, Brazil

For the first time, researchers detected the presence of the whitefly (Bemisia tabaci) of the Q biotype in Mato Grosso, Brazil. Considered to be invasive in Brazil, this breed has the characteristic of being more resistant to a range of insecticides used in agriculture. It is not yet known if this breed is already present among the region's crops.

The identification was made during work coordinated by Embrapa researcher, Rafael Pitta, with the assistance of agronomy undergraduate students from Federal University of Mato Grosso (UFMT), and was assisted by researchers from Unesp (Botucatu-SP), where the identification was made using molecular biology techniques. DNA analysis is the only way to differentiate species, since they are visually identical.

The whitefly Q biotype originates in the Mediterranean region. It was first collected and identified in Brazil at the end of 2013 by a group of researchers at plantations in Rio Grande do Sul. Since then, it has spread throughout the country, and has been found in the southern states, as well as in São Paulo and Goiás. The whitefly causes damage to several crops, with a greater economic impact on sweet peppers, soybeans and cotton.

According to Rafael Pitta, the initiative to search for the pest in Mato Grosso began after attending a presentation at a scientific event, in which he saw that this whitefly breed is present in flower plantations in the state of São Paulo. As plants from that region are sent throughout the country, there would probably be insects found in other regions.

Agronomy students taught by Rafael at UFMT collected whiteflies found in tomato, hibiscus, cat's tail, angel trumpet and lantana, in the floriculture and the gardens of their own residences. Of all the individual insects analyzed, two of the five present in the lantana were of the biotype Q. The others were of the biotype B, which are more common in the region.

Pitta explained that the findings make apparent the need for further research to see if this whitefly breed is already present in the state's crops. The greatest risk is for soybean and cotton crops.

"As this breed is resistant to a range of insecticides, the spraying of pesticide could result in the individuals of this breed is selected from others, making it more difficult and more expensive to control the whitefly," said Pitta.

According to Pitta, while not delving into research, the best prevention tool is integrated pest management (IPM).

"The exaggeration in the applications increases the selection pressure of this breed, favoring the establishment of it in crops. The best thing to do is monitor the crop and only apply the insecticide when the infestation begins damaging the crop, said Pitta.