Biological control achieves high efficiency against spider mites on strawberries

The adoption of biological control, within the scope of integrated pest management (IPM), can achieve up to 80% control efficiency against the spider mite, the main strawberry pest in the Federal District, especially in the dry and hot period of the year. The release of natural enemies in the crop, if carried out at the exact time and in the correct quantity, guarantees high levels of control and contributes to reducing the number of chemical product sprays.

“In recent years, strawberry producers have reported a lower efficiency of chemical control and this is mainly due to the pest's resistance to the chemical products (acaricides) used”, analyzes researcher Miguel Michereff Filho, from Embrapa Hortaliças (Brasília , DF). The lack of options for registered products for strawberry cultivation and indiscriminate use, such as increasing the frequency of spraying and/or the dose used, favors an increase in the spider mite's resistance to chemical control.

During training held for Emater/DF technicians and producers from the Brazlândia Rural Center, on the 16th, the researcher explained the principles of IPM, focusing on strawberries, and emphasized biological control as a strategy to reduce problems associated with resistance. “When spider mite infestation is not controlled, there can be an 80% reduction in strawberry production”, estimates Michereff.

The Brazlândia region is the main hub for strawberry production in the Federal District. According to data from Emater/DF, in 2018, the area cultivated with strawberries in the Federal District was 167 hectares, distributed among around 250 rural producers. Total production was more than 7.500 tons, with productivity per hectare estimated at 37.500 boxes of 1,2 kg. The production cost of one hectare of strawberries, in the Federal District, was in the range of R$125.000,00.

The main message given to training participants was that, although the cost of biological control and chemical control is practically equivalent, there are indirect savings and other advantages associated with the adoption of IPM, such as a reduction of between 30% and 40%. % of spraying frequency, which contributes to greater crop sustainability. “There is also a demand from the consumer market for healthier foods, which may make producers rethink other means of control”, ponders the researcher.

natural enemies

The natural enemies of the spider mite, recommended for biological control in strawberry plantations, are predatory mites known as phytoseiid mites. Their use works very well in the South and Southeast regions because they are adapted to environments with humidity around 60%. According to Michereff, in the Federal District, especially in winter, when relative humidity is very low, it is necessary to advise producers on the release of predatory mites so that they remain viable for longer within the crop.

He recommends that producers carry out sprinkler irrigation on strawberry plantations, right before releasing natural enemies, because this creates a microclimate with greater humidity, which is favorable to the activity of predatory mites. “Producers need technical knowledge to effectively use biological control. Before releasing the predator, it is necessary to comply with some cultural practices in the field and establish favorable conditions so that the natural enemy can act to control the pest”, he comments.

Training

Training courses for technicians and rural producers have been the basis of the project “Promotion of Integrated Pest Management in Vegetable Production in the Federal District”, which aims to restore the adoption of good agricultural practices aimed at pest management in four agricultural crops: strawberry , lettuce, tomato and pepper.

The objective of the training has been, according to the researcher, to make a diagnosis, exchange experiences and level knowledge so that, in a second stage, based on partnerships and institutional articulation, it is possible to install Technological Reference Units (URT) for implementing IPM in these four important crops in the Federal District.

In the project schedule, the next courses will include lettuce (September), tomatoes (October) and peppers (early 2020). The project is carried out in technical cooperation with Emater/DF and with funding from the Federal District Research Support Foundation (FAPDF).