Jill Scheidt, agronomy specialist with University of Missouri Extension, is finding insects and aflatoxin in fields across southern Missouri.

Scheidt scouted fields earlier this month and found two damaging caterpillars — fall armyworm in fescue pastures and podworm in soybean fields. She says farmers should be scouting their own fields.

Soybean findings
Scheidt scouted soybean fields ranging from beginning to full seed and found sudden death syndrome is showing up in most fields.

Soybean fields with SDS will find yellowing between the soybean leaf veins, followed by necrosis of the leaf, while veins remain green. SDS fungus is in the roots, so foliar fungicides will not help, Scheidt says. Instead, choose a resistant variety and utilize crop rotation.

Cool, wet conditions early in the growing season encourage development. Symptoms do not appear until mid-summer, however, usually following cooler temperatures or high rainfall during bloom or pod fill.

Scheidt observed podworms at threshold level in second crop and late-planted soybeans.

Podworms differ from other caterpillars. These insects have four prolegs in the middle of the body. Identification is important because most other caterpillars are foliage feeders, Scheidt says. The threshold level is one per foot of row or 5% pod damage.

Corn problems
Aflatoxin is being reported in some corn fields.

This type of toxin is produced by aspergillus ear rot. Development of aflatoxin often occurs during drought and high humidity conditions.

Scheidt says farmers should harvest dryland corn separate from irrigated fields, adjust the combine to spit out broken and lightweight kernels, and clean the combine.

FUNGUS CHECK: Kernels infected with aspergillus (greenish fungus) as well as diplodia (white fungus) and possibly fusarium (starburst pattern on kernel) are present.

The maximum acceptable level for aflatoxins for human consumption, dairy and immature animals, and unknown animal feed source is 20 parts per billion. Breeding beef cattle, swine and poultry maximum aflatoxin level is 100 ppb; finishing swine is 200 ppb; and finishing beef cattle is 300 ppb.

Lower aflatoxin levels by mechanical separation of moldy and lightweight kernels, blending and alternative feeding.

Pasture bugs
Scheidt observed fall armyworm at threshold level in pasture fescue fields.

"Scout grass pastures frequently as a lot of foliage damage can occur overnight," Scheidt says.

Fall armyworm range from 1/16 to 1 1/20-inch long. They start out light green and turn dark with light colored lines running lengthwise.

"Outbreaks are more likely after periods of drought," Scheidt adds. "Threshold is four armyworms per square foot."

Source: University of Missouri Extension