By Hayden Schug
Corn earworms, also known as podworms, headworms, bollworms, and several other names, have increased in Maryland following flights up from the South and higher local emergence. Growers should remain alert for damage in double-cropped soybeans and sorghum. While this pest is a familiar concern in sweet corn, it can also cause serious yield losses in other summer crops when populations are high.
In soybeans, larvae feed directly on pods and developing seeds, with the greatest risk occurring between the R1 and R5 stages. Fields that are flowering or setting pods are especially attractive to egg-laying moths. Female moths typically deposit eggs in clusters near the upper canopy. Larvae may be green, yellow, or brown, with faint stripes along the body and small spines on the skin.
When scouting, ensure that earworms are identified correctly, as they have a different economic threshold than other caterpillars commonly found in fields, such as soybean loopers and cloverworms (Figure 1). Damage can be detected by looking for chewed pods or flowers. However, the absence of visible chewing damage does not mean the pest is absent. Soybeans often abort young pods or flowers that have been damaged, redirecting energy toward intact pods and flowers. Earworms are voracious eaters, it has been shown that one large earworm per row foot in wide-row soybeans can reduce yields by 1.93 bushels per acre.
Source : umd.edu