Helicoverpa outbreaks put pressure on Intacta crops at the beginning of the 2022-23 harvest

The strong pressure of caterpillars of the genus helicoverpa in Intacta soybean crops in Mato Grosso do Sul, Mato Grosso and Maranhão draws the attention of producers and researchers. The dry climate that has affected these areas, experts say, directly influences the increase in the presence of caterpillars in the initial phase of the oilseed crop. Although the infestations do not yet cause panic, sources emphasize, it is necessary for the producer, at this time, not to neglect monitoring the plantations.

According to researcher Germison Tomquelski, from Desafios Agro, based in Chapadão do Sul (MS), significant populations of helicoverpa were detected in different parts of Mato Grosso do Sul and Mato Grosso, such as the regions of BR-163, Vale do Araguaia, Campo Verde and Rondonópolis. “The presence of caterpillars is representative and is requiring insecticide applications at the beginning of the harvest”, summarizes Tomquelski.

“We are facing a different scenario this year. It is possible that there is a tendency for more intense occurrence of helicoverpa in intact soybeans. This is a group of polyphagous pests, which multiply in the production system. It may be more challenging to deal with them from now on”, he highlights. According to him, it is not yet known whether the predominant populations of the pest observed in MS and MT constitute Helicoverpa armigera, Helicoverpa zea or hybrid.

For Tomquelski, the application of insecticides, whether biological or chemical, should preferably occur when the pests are in the initial stage of development. “In 1st and 2nd instar caterpillars, bioinsecticides such as baculoviruses show control efficacy of around 90%. For larger caterpillars, we recommend integrating chemical insecticides into management.”

'Escape from caterpillars'

“We consider it essential for producers to anticipate the problem, through monitoring, and have appropriate tools on hand at the right time to control it”, reinforces Guilherme Ohl, researcher at Ceres Consultoria, in Mato Grosso, Primavera do Leste. Ohl adds that, recently, he toured the state and saw pressure from helicoverpa above average, for this harvest period, in crops “from Parecis to Xingu”.

Still in relation to the control of helicopter, Ohl understands that “one technology must defend the other”. “Baculoviruses are fundamental within integrated pest management (IPM), as well as chemicals, the 'traps'”, he ponders. “The ideal is to start the selected treatment, depending on the crop, when monitoring indicates the average presence of a helicoverpa per meter, in the vegetative phase of soybeans and ½ caterpillar of the genus, per meter, in the reproductive stage.”

However, according to Guilherme Ohl, nowadays, “the biggest fear” of experts is that other species of caterpillars, in addition to helicoverpa, “are ‘escaping’ the control of Intacta technologies”.

“In the last two harvests, the Helicoverpa zea It escaped from corn, went to cotton and this year we see the pressure occurring in soybeans”, he warns. “We also noticed an increase in the population of caterpillars Spodoptera frugiperda, Heliothis virescens e Rachiplusia nu. Possibly, there is an adaptation of these pests to Bt soybean technologies, which occupy 86% of the oilseed planted in the country.”

In the region of Balsas (MA), where agronomist and consultant Octavio Augusto Queiroz, from Evoterra, works, the beginning of the soybean harvest has been marked by outbreaks of Helicoverpa spp.. “We have had an increase in caterpillar pressure for two years here. We believe this comes from the correlation between pests of off-season corn and soybeans. It is possible that this scenario will worsen in the coming years.”

Technical manager of AgBiTech Brasil, agronomist Marcelo Lima assesses that outbreaks of helicoverpa at the beginning of the harvest, as well as the resilience of caterpillars to biotechnology, generate concern, even though the scenario appears to be less serious compared to 2013 and 2014, when the Helicoverpa armigera caused serious damage. “Today we have more effective management tools, from chemical and biological insecticides to moth attractants.”

Information on Helicoverpa resistance in Intacta soybean crops

We publish several articles and technical articles on the resistance of helicoverpa in Intacta soybean crops -- or related to the topic. Below are five examples:

1. Pest pressure in soybean crops

2. Helicoverpa Hybrids

3. Researchers warn of Helicoverpa attacks on cutting-edge biotechnologies in corn and cotton

4. Preservation of Bt biotechnology

5. Resistance management in Bt cultivars