Scientists Push Integrated Pest Management for Brazilian Farmers

Scientists in Parana,Brazil are advising farmers that the use of Integrated Pest Management (IPM) techniques is the best way to keep the corn earworm below the economic threshold while at the same time not making unnecessary insecticide applications. The central principal of IPM is to maintain a healthy balance of beneficial insects that can reduce the need for chemical control.

According to Paulo Cesa, an agronomist in the extension service of Emater/PR in western Parana, producers could save a lot of money by not over applying insecticides out of fear of the corn earworm. In his district, the corn earworm populations increased a little in mid-November, but then their numbers quickly declined.

He attributes the decline to attacks from natural enemies such as spiders, wasps, flies, and beetles that help to control the caterpillars. In research conducted by Embrapa, one tiger beetle consumed 14 small corn earworm caterpillars in a period of 14 hours. It helps to illustrate the importance of maintaining beneficial insects especially during the first 45 days of the soybean crop.

A researcher for Emater in Campo Mourao (also located in western Parana) reported that in 20 demo plots that used Integrated Pest Management, none of the plots needed an insecticide application prior to the soybeans starting to flower. In contrast, those plots that did not employ Integrated Pest Management needed two applications of insecticides before flowering.

Scientists are advising farmers that the most important thing to do is to monitor their fields twice a week to accurately judge the level of insect populations, both beneficial and harmful. Only with an accurate assessment of the insect populations can a farmer determine when the economic threshold has been reached.

It is estimated that farmers in the state of Parana who do not accurately monitor insect levels in their soybean and corn fields, both beneficial and harmful, will make six insecticide applications during the 2013/14 growing season. Farmers that use Integrated Pest Management will make 2.5 applications. Additionally, farmers should only use selective insecticides that target specific insect species such as the corn earworm and not broad based insecticides that kill both harmful and beneficial insects.