Adequate root reserves are needed for winter survival, spring growth, and regrowth immediately after harvest. The greatest impact of clover root curculio on alfalfa may be the effect of larval feeding on root reserves and subsequent plant mortality during the growing season. Feeding damage to the root increases the severity of root rots. This can be an additional cause of declines in plant or stand vigor. Damage may be intense in some portions of the fields, such as along the margins, but slight in others.
Soil moisture is a very important factor.
Losses to clover root curculio can be significant when the stand is under drought stress but do not occur when soil moisture is adequate. The lack of reliable means of assessing CRC infestations in fields makes it very difficult to determine the potential for economic losses. In addition, there are no registered insecticides to control or reduce the numbers of CRC larvae in infested fields. Crop rotation Rotation of alfalfa or clover to grasses or row crops other than soybeans will remove the food source for larvae trapped in the soil and the types of plants that would stimulate adults to enter the field to lay eggs. Isolation from Existing Legumes New fields should be as far away from existing clover, alfalfa, or other legumes as practical.