Corn under increasing pressure from Helicoverpa caterpillar in Brazil

Brazilian consultants and researchers revealed to AgroPages that the pressure applied by the Helicoverpa caterpillar on crops is increasing season after season.

For at least three harvests, the pest's attacks have intensified in strategic areas of the country's agribusiness, including the western regions of the Brazilian state of Bahia and the state of Maranhão.

Recently published reports and research have highlighted the need to promote change in the behavior of producers, given the increasingly severe damage caused by this pest to corn from the second Brazilian harvest to summer corn.

Multcrop

For more than two years, two renowned consultancies in the country, Evoterra and Multcrop, have been researching and developing new management strategies to minimize Helicoverpa's potential damage to the cereal both now and in the future.

With over 80,000 hectares of crops under management, Evoterra serves producers in Maranhão, Piauí and Tocantins, while Multcrop covers around 170,000 hectares in western Bahia and Piauí, and it will also reach Tocantins soon.

″About 70% of the 30,000 hectares of corn assisted by Multcrop between Bahia and Piauí already live with Helicoverpa,″ said agronomist Tiago Souza, founding partner and director of Multcrop, who is an expert in herbology and plant protection.

Left: Tiago Souza

Right: Octavio Augusto Queiroz

Agronomist Octavio Augusto Queiroz, director of Evoterra, who is a specialist in plant protection and an e pert in seed production, said that in the last harvest, the consultancy limited the effects of Helicoverpa's on maize once and for all, stating that ″due to the high pressure of the pest, today it us a real problem.″

Evoterra and Multcrop both affirmed the importance for producers to time the exact moment to apply insecticides to control Helicoverpa in corn.

″The moment of spraying is more important than the dose of agrochemical used. We carry out integrated pest management and use traps for moths (‘attract and control’),″ said Queiroz.

″The target is difficult to control. We have validated baculoviruses among the tools recommended to farmers. If there are moths in crop traps, inevitably there will be Helicoverpa eggs in the crop,″ he added.

As Queiroz observes, the successful applications of baculovirus, whether solely or combined with chemical insecticides, should happen when the maize is in the ″pre-feathering″ stage, or while the ear's 'hairs' have not yet emerged.

″Therefore, when hatching, the caterpillar already enters the ear contaminated and tends to die. This is the crux. Applications from R1 (tanning), in turn, make control much more difficult,″ he said.

Souza said, ″It is essential today to review some practices. In the Mapitoba region, we now have a magnifying glass over corn, due to Helicoverpa and Spodoptera. The biotechnology crash has become a reality, we are losing grain.″

According to Souza, studies show that in the area covered by Multcrop, there were recent losses of 4 to 4.5 sacks of cereal per hectare, given the pressure exerted by Helicoverpa.

″In a simple calculation, if there are around 250,000 hectares of corn in this region at R$70 a bag, we are talking about R$ 70 million in losses, and this in a small area compared to Goiás, Mato Grosso and Paraná,″ he said.

″We are looking for alternatives. We started to work with baculovirus, and we saw that they solve the issue well. We cannot eliminate the caterpillar with any tool, but with the viruses, we have seen significant damage reduction in the 70% range,″ he added.

Souza also noted that in cotton areas covered by Multcrop, the use of attractants captured more than 70 months per meter.

″This is relevant data. This tool will become more and more common in different cultures, even more so at a time when the industry has little capacity for innovation in chemical molecules and mechanisms of action,″ he said in conclusion.

(Editing by Leonardo Gottems, reporter for AgroPages)