Illinois Field Crop Applicators Practice Test

When is alfalfa most susceptible to potato leafhopper damage?

1. During the flowering stage

2. After the first crop

3. Just before harvest

4. During the first frost

The correct answer is: After the first crop

Alfalfa is most susceptible to potato leafhopper damage after the first crop. This susceptibility arises because, during this period, the regrowth of alfalfa often attracts these pests, which feed on the new tender shoots. The potato leafhopper feeds by sucking the sap from the plant, which can lead to significant stress on the alfalfa, stunting its growth and ultimately impacting its yield and quality. During the flowering stage, the plant is generally more robust and established, reducing the overall impact of the leafhoppers compared to when the crop is younger and newly regrown. Just before harvest, the plant may start to mature, which could make it less appealing to pests, and during the first frost, the cold conditions typically reduce pest activity and population dynamics. Therefore, the period after the first crop is critical for monitoring and managing potato leafhopper populations to protect alfalfa health effectively.