Is an insect always a pest?

| February 19, 2018

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In keeping with the theme of this week’s Farmer stories, our Script of the Week also focuses on pest management.

Before taking actions to control pests in their fields, farmers need to assess at what point spending money on pest control is justified. If farmers spend money on a pesticide to control pests that are causing only a small amount of damage, they may actually lose money.

To minimize damage, farmers should examine their fields regularly to monitor pest population levels, and apply controls only when infestations reach the level of economic damage. Economic damage is the point at which the loss of income from the damaged crop is greater than the cost of buying and applying a pesticide or other control product.

This week’s script shows how pesticides and other pest control methods may not be necessary if the damage caused to crops is minimal. You may want to talk to an agricultural extension worker to find out what the economic damage levels are for commonly grown crops in your region, and include this information in your broadcast. This will help farmers in your listening audience to better understand the concept of economic damage.

For example, in Guatemala, farmers learned how to test for economic damage levels in stored beans. They were taught to check samples of stored beans every 30 days to look for weevil damage. If more than four out of every 100 beans (4%) were damaged, the farmers were advised to control the pest. If the percentage of damaged seed was less than four percent, there would not be a significant reduction in germination, nutritional quality, or sale price of the beans.

Also, maize farmers in some African countries have been advised to use control measures against Fall armyworm between germination and flowering only if two or more of 10 maize plants in their fields show signs of recent damage. Keep in mind that the ratio may be different in your area, so always check with extension agents or other experts.