Penicillium on corn, stink bugs on soybeans
Some of the southwest Missouri corn fields are showing signs of penicillium ear rot, and the biggest concern for soybeans right now are stink bugs.
Brie Menjoulet, agronomy specialist with University of Missouri Extension in Hickory County, scouted fields in southwest Barton County between Lamar and Nashville on Aug. 24.
Corn fields scouted ranged from dent stage to maturity. Penicillium ear rot was found in all the fields scouted this week. Corn earworms were found in several ears of the dent-stage corn.
"Because corn earworm feeding damage can increase the chances for penicillium to infect the ears, management strategies that help control corn earworm populations and damage, such as variety selection, tillage practices, and crop rotation, may help reduce infection of penicillium in next year's crop," said Menjoulet.
Soybeans scouted this week were in full bloom to R3 pod development stages.
"Nearly all plants looked healthy and feeding damage from insects remains minimal so far. However, it is time to start scouting for stink bugs," said Menjolet. "First, or possibly second, generation stink bugs are reaching maturity and laying eggs."
Stink bug nymphs and adults feed on soybean stems, blooms, pods, and seeds. Feeding damage can delay maturity, cause abnormal production of leaflets and pods, and can affect seed quality.
Eggs can range in color from nearly black to pinkish-white, are barrel-shaped and will be in cluster of 10 to 30. Stink bug distribution within a single field can be patchy.
When scouting for nymphs or adults, use a sweep net or drop cloth at several sites in the field. Insecticide application may be needed if older nymphs or adults reach one per foot of soybean row during the R5 and R6 seed development stages.
For more information on this scouting report or to learn how you can receive it by telephone each week, contact the MU Extension Center in Barton County at 417-682-3579.