Present from the north to the south of the country, the insect has become the main pest inside corn crops in recent years, causing great financial losses
(Credit: Embrapa)
With a little less than half a centimeter, Dalbulus maidis or corn leafhopper, as it is popularly known, is one of the most devastating pests of Brazilian crops. Studies point out that, here in Brazil, it has been observed in cereal crops since 1930, becoming a major problem in the field only in mid-2015.
“This small insect has a devastating potential for damage, and in some cases, it can decimate crops if not effectively controlled, causing farmers great financial losses”, says Bruno Arroyo, agricultural engineer and market development manager at Agrobiológica, a company of the Crop Care holding.
The leafhopper is no longer a pest exclusive to corn seed production areas, but is now present in virtually all producing regions and in the different stages of grain cultivation, both first and second crop. The first major damage caused by this insect was observed in the states of Goiás, Bahia and Minas Gerais.
Although it has been present in Brazil for a long time, the first major report of the pest was recorded in 1985, in Minas Gerais. However, it is possible to find descriptions of the pathogens that cause stunting dating back to 1971 in São Paulo.
There are several species of corn leafhopper, with the Dalbulus maidis, which originates from Mexico, being the biggest troublemaker in corn farming. It feeds on the plant’s sap, but in addition, it is the transmitter of the bacterium that causes stunting, right from the initial planting cycles.
One of the damages caused is in the photosynthetic capacity of the plant, bringing spots and the well-known stunting. Another characteristic is that the plants may become more susceptible to toppling, especially towards the end of the cycle. There are also cases of fumagina, when there is high pressure of the pest in the fields.
In relation to the management of the plague, Arroyo leaves a warning to producers: avoid “tiguera” corn. This volunteer plant, which grows in areas of other crops or during fallow periods, serves as a shelter for the leafhopper, which facilitates the reproduction of the insect. It is a simple thing, but the practice can reduce the impacts of a large pest infestation.
The symptoms of the presence of the leafhopper are only observed after about two to three weeks of contamination. For this reason, it is important that the producer observes the plantation very well and is able to identify the presence of the insect, being able to start a preventive management, once the plague is already installed.
“The most critical period, is what we call V4 to V6, where the plant is defining its productive potential, therefore, during these phases, it is more sensitive to suffer the impacts. It is in this period that the producer must be on maximum alert, but it is also important to stay alert from the emergence of the plant until V8, when the plant is already bigger, but equally exposed”, he informs.
According to the specialist, areas where there are planting cycles throughout the year are the most affected. “The leafhopper is a vector insect and has a much higher migration capacity compared to other pests. And when the problem is not treated correctly, the consequences incur great losses. In some cases, even the whole plantation”, he adds.
Also according to Arroyo, as soon as the pest became a serious problem in the fields, farmers resorted to chemical insecticides, which worked in some applications. However, due to the climate, especially in regions of the mid-west, where there is no occurrence of mild temperatures, which usually act as a natural control of these pests, management becomes even more challenging.
“Over time, two or three applications were no longer as effective as before. And large volume applications have ended up creating insects that are resistant to certain active ingredients. It was observed that the chemists delivered an average control rate of about 60%, which is good, but often not good enough. And that’s when many decided to adopt the combined use of biological pesticides”, he explains.
According to a projection by the Sindicato Nacional da Indústria de Produtos para Defesa Vegetal (Sindiveg) (National Union of Industry of Products for Plant Defense), in 2022, there will be a 100% increase in the area treated with pesticides, against plagues in the first and second harvest corn crops.
Biologicals, which have recently started to be used in combination with chemicals, decrease pest resistance and increase the efficiency of control, especially in plantations where the incidence of these insects is already very high.
Today, biologicals are strong allies, especially in the fight against the corn leafhopper. In this scenario, the fungus Isaria fumosorosea is currently the most widely used active ingredient. But for a more assertive action of prevention and elimination of the pest, other agents combined in formulation, such as metabolites, spores, and ready-made structures of the fungus in the product, make the application more efficient, and offer a faster control, which is a differential for the producer.
The fungus acts on the insect by contact, whether in the nymph or adult stage. It causes a kind of infection in the leafhopper once the product is released in the field. Isaria fumosorosea, upon contact, forms an internal colony within the insect, serving as a source of multiplication of the fungus. Arroyo explains that if this insect dies, it can sporulate more fungus into the environment, infecting other insects. “You continue to have contaminated insects in the environment, which helps in a long term residual control, since the application is combined with chemical products,” he adds.
This type of differentiated formulation technology is called Bioshock, present in the product Aptur, developed exclusively by Agrobiológica. Today, about 1.5 million hectares are treated with this technology, just for corn leafhopper control.
“Aptur does not harm the plant or the environment, and still helps the producer to ensure long-term control throughout the planting, whether or not it is used in combination with chemicals. This helps to reduce spending on products, applications, and labor, since control becomes more efficient, increasing the profitability of the farmer,” he concludes.
About Crop Care
Crop Care is a Brazilian holding company, responsible for important brands in the market of chemical inputs, biologicals and special fertilizers.
Among Crop Care’s invested companies are Agrobiológica Sustentabilidade, a complete and innovative platform for biological and on farm solutions; Perterra and K2, which has an extensive and complete portfolio of herbicides, fungicides, insecticides and post-patent agrochemicals; and Union Agro, specialized in special fertilizers.
Through partnerships with distributors and cooperatives, and direct access to agricultural companies, Crop Care is present in major producing regions in Latin America.
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