Corn leafhopper returns with full force in the 2022 harvest

Due to the strong drought and frosts that occurred in the main corn producing regions of the country in 2021, the farmer had the feeling that there was a decrease in damage caused by pests and that, therefore, intensive management with insecticides was not necessary. However, the first plantings of the 2022 harvest show that the corn leafhopper (Dalbulus maidis) has not gone away and is already present in high concentrations in practically all regions. One of the most worrying pests for the farmer, it continues to pose a risk to the winter crop. Despite the low incidences observed in the 2021 harvests, the lack of management, combined with tiguera corn plants, contributed to the leafhopper population increasing significantly.

The threat to the harvest has encouraged the movement of producers and organizations in the sector. In January 2022, for example, the Ministry of Agriculture, Livestock and Supply (Mapa), together with the Association of Soy and Corn Producers of Mato Grosso (Aprosoja MT), the Brazilian Agricultural Research Corporation (Embrapa) and the Institute of Agricultural Defense of Mato Grosso (Indea MT) carried out a technical visit in the state of Mato Grosso to outline contingency measures and monitoring of leafhoppers and corn stunting with the main producers of the crop.

With the capacity to cause up to 80% of production losses, the leafhopper is not something that can be ignored. The insect is a vector of corn stunting disease, caused by mollicutes that obstruct the conductive vessels of the corn plant and cause smaller plants, reddish color or fine streaks on the leaves and, mainly, unproductive ears. It is no surprise, therefore, that more and more farmers are looking for options capable of protecting corn crops; scenario in which biological products are gaining prominence. Recent research by Spark Smarter Decisions showed the growth of the sector: of the main corn producing states in the country, 7% used organic products in farming in 2019, which represented investments of R＄66 million in the 2018/2019 harvests. In 2021, the number increased to 11% and investments almost tripled, reaching R＄176 million in the 2020/2021 harvests.

As important as attacking the problem, however, is knowing the right time to act. As the sowing peak for this crop takes place in February, the time to act is now: a well-executed seed treatment helps to contain the leafhopper infestation in the first few days after the plant emerges, but, when it has two leaves, It is necessary to start management with pesticides - mainly combining biological and chemical insecticides. After several studies carried out with the country's main research institutions, we saw that chemical pesticides alone have not been able to contain the spread of the pest. However, the association with the biological pesticide reduces the number of symptomatic plants by 20% and, consequently, also reduces productivity losses caused by corn stunting.

We are alongside the producer with solutions such as Bovéria Turbo, an insecticide registered to control the corn leafhopper. We always reinforce that preventive management is essential to control the pest and it needs to start early: the first applications must be carried out 20 days after planting (right at the V2 vegetative stage). This month of February is the ideal time for producers to adopt measures that will avoid compromising the corn harvest.