By Scout Nelson
Recent reports from South Dakota show that grasshopper numbers are increasing in some regions, with many fields already experiencing crop loss along their edges. Although grasshoppers may not always be visible at first, mowing or the natural decline of grass around field edges often forces them to move into nearby crops in search of food. Unfortunately, crops often become their target.
Fields that were planted later than usual are at greater risk. These plants are not as strong at this stage, making them more vulnerable to grasshopper feeding. In severe cases, entire plants may be eaten. Large populations typically begin feeding on field edges before spreading further into the crop, making scouting and early detection essential.
Farmers are advised to check border rows first when scouting. In some cases, treating only the field edges with insecticides can slow grasshopper movement and protect the crop without the need for full-field spraying. However, this works best when treatments are applied as grasshoppers start moving into crops, not after they are established.
Managing grasshoppers is easier when they are still in the nymph stage because they are smaller and more sensitive to treatments. Once they become adults, they are harder to control and often need higher chemical rates. Farmers are reminded to always follow product labels and avoid using the lowest recommended rate for grasshopper management.
The recommended threshold for grasshoppers is 21 to 40 per square yard along field margins, or 8 per square yard inside the field. Farmers can check populations by visualizing a square yard around their feet and counting the grasshoppers, repeating the process until reaching the edge of the field.
Photo Credit: pexels-tudsaput-eusawas
Categories: South Dakota, Crops