Green cloverworm: Management decisions

Treatment recommendations for green cloverworm are based on sampling with a drop cloth. Sweep net sampling based recommendations do not exist. Below is a description of how to sample with a drop cloth. Remember to scout each field and each variety separately.

Drop cloth technique
• Walk 100 feet in from the field edge.
• Place a 1-foot-long strip of cloth on ground between the rows.
• Bend the plants of one row over the cloth, and shake them vigorously.
• Count the number of larvae on the cloth.
• Repeat the procedure four times for each 20 acres of the field.
• Determine the average number of larvae per foot of row.
• See Table 1 for the number of larvae per foot of row necessary to justify insecticide treatment for green cloverworm.
• If the number of larvae is below the economic threshold, sample your fields again the following week, or a third week if necessary.

Other insects are capable of defoliating soybean (e.g., bean leaf beetle, armyworms, etc.). Even if green cloverworms are below treatment levels, fields may still warrant treatment if the combined defoliation of multiple pests approaches 20 percent. Remember people tend to overestimate percent defoliation, so be sure to accurately assess leaf tissue removed on the entire plant instead of just the upper canopy.