Natural predators key controller of Brazil earworms
Natural predators are proving a deadly enemy of the devastating soybean pest, corn earworms (Helicoverpa armigera) in Brazil, according to the agricultural research corporation, the Embrapa. The average mortality rate of earworms from the actions of parasitoids, nematodes and pathogens is running at over 60%, an Embrapa study has found. It evaluated 1,387 earworms collected across Parana state. Fewer than one in three (29.8%) had fully developed in a healthy manner, while the main killers were parasitoids, producing a mortality rate of almost half (49.8%). Natural predators are an important controller of earworms, the corporation concludes. “The abusive application of non-selective insecticides will only exacerbate the problem of these pests and unnecessarily increase production costs,” the Embrapa’s study authors comment. The authorities declared a state of emergency and widened controls against the pest last year (Agrow No 677, p 17).