The Asiatic garden beetle (AGB) continues to cause problems in cotton this growing season. AGB is an annual white grub species, meaning it completes its life cycle within one year. The chestnut-colored scarab beetles (Fig. 1) currently emerging and flying originated from eggs laid in the soil last year.
Asiatic Garden Beetle Continues to Threaten Pockets of Cotton Production
(Updated: July 1, 2026, 8:13 a.m.)
Asiatic Garden Beetle in Cotton
Figure 1. Asiatic garden beetle (A) ventral, (B) dorsal, and (C) lateral views. Photos by Steve Upperman.
Adults defoliate plants by feeding inward from the leaf margins. Because AGB adults are nocturnal and shelter beneath the soil surface during the day, feeding damage often appears to occur overnight. This damage resembles injury caused by grasshoppers or slugs (Figs. 2-3). One giveaway that AGB is present in a field is the presence of dead adults on the soil surface.
Figure 2. Asiatic garden beetle feeding starts on the leaf edges and moves inward, resembling other leaf eating pests.
Figure 3. (A) Asiatic garden beetle feeding damage compared to (B) deer which feed directly on the plants, removing the terminal growing point and entire leaves.
Based on field observations, infestations seem to be worse in sandy soils, no matter what crop was grown there before. AGB is a generalist and can feed on over 100 species of plants including many crops and weeds. Management efforts should therefore be targeted to sandy areas with a history of AGB, particularly those planted to cotton. Successful foliar pyrethroid (common examples include Warrior II, Engido, bifenthrin, etc) applications will result in many dead beetles on the soil surface the following morning (Fig. 4). Application timing—day or night—does not affect efficacy, as beetles must consume treated foliage for the insecticide to work.
Figure 4. Asiatic garden beetles that feed on insecticide treated leaves are found lying dead on the ground in the daytime instead of hiding beneath the soil surface.
How Much Longer Will the Beetles Feed?
We have received reports of additional beetles appearing and defoliating cotton in the weeks following treatment, necessitating repeat applications. To better understand this pattern, we have been monitoring AGB emergence with pitfall traps (Fig. 5) and adult flight with antifreeze milkjug traps (Fig. 6) in a Northampton County field this season.
Figure 5. Pitfall traps (deli container filled with soap water is placed in the ground so rim is flush with soil surface) used to detect Asiatic garden beetle emergence from soil on May 18, 2026.
Figure 6. Antifreeze milkjug trap used to monitor flight of Asiatic garden beetles on May 21, 2026. Each trap consists of a 4 ft plastic fence post with a milkjug with a large hole cut in each non-handle side and ziptied to the post.
In a Northampton County cotton field, adult emergence (Fig. 7) began the week of May 18, with flight (Fig. 8) beginning shortly after. Peak activity (both emergence and flight) occurred during the week of June 15 this year, about 1-week later than previous years. Adult populations have been declining since. These findings suggest that the majority of beetles in the environment are now emerged and active and that significantly fewer will emerge throughout the remainder of the summer.
Figure 7. Total Asiatic garden beetle adults sampled from pitfall traps over time from a cotton field in Northampton County, NC.
Figure 8. Total flying Asiatic garden beetle adults sampled from antifreeze milkjug traps in a cotton field in Northampton County, NC.
It is important to note that adults live for 30 or more days. The apparent "recolonization" of treated fields is likely not true reinfestation, but rather an influx of beetles from nearby areas, drawn by sandy soils and cotton foliage. Adults fly on warm nights when temperatures exceed 70°F, conditions that have persisted over the past several weeks.
Late-planted cotton is most susceptible to AGB feeding damage, and significant defoliation may lead to planting a different crop, such as soybeans, this late in the season. Earlier-planted stands should be able to tolerate feeding with active management and grow out of the injury.