In 2015, we received plant samples of soybean that had small red maggots under the epidermis. Now, in 2017, we are starting to receive reports of these same insects being found under the epidermis of soybean in different parts of South Dakota.
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While quite uncommon for lightning to damage row crops, it does happen. Thunderstorms can have lightning that can burn soybeans plants leading to their death.
Most of the Great Plains, of which Western South Dakota is part of, have always been considered a semi-arid area of the U.S. This region is characterized by hot, relatively short summers, and usually cold, dry winters.
Soybeans in South Dakota are in their moisture-critical reproductive stage. Drought stress during this growth stage can significantly impact yield, so here are some things to look for.
According to USDA-NASS crop progress report for the week of July 17, 49% of the soybeans in South Dakota are at flowering. The flowering growth stage is also the time when white mold infection is initiated. The white mold pathogen infects the soybeans through the flowers that are senescing after pollination.
While scouting wheat fields throughout South Dakota, we have started noticing the presence of bleached heads scattered throughout many different fields. These discolored heads are the result of an infestation of the wheat stem maggot.
While scouting fields this week, we observed winged (alate) soybean aphids in Southeast South Dakota.
Barley yellow dwarf is starting to develop in winter wheat. Barley yellow dwarf is caused by the Barley yellow dwarf virus (BYDV). This disease usually becomes more distinct at flag leaf emergence. A typical symptom of Barley yellow dwarf is the purplish-yellow color of infected leaves, especially the flag leaf.
In South Dakota, the most commonly encountered mites in wheat are wheat curl mite and brown wheat mite. In addition to feeding, wheat curl mites are vectors of Wheat streak mosaic virus. Brown wheat mites can build up large populations and injure wheat through feeding. There are other species of mites that may also be observed in wheat, but generally do not reach populations large enough to cause significant injury.
Recently, there have been reports of brown wheat mites throughout central and western South Dakota. The brown wheat mite is generally more of an issue in the drier parts of the state, or in areas experiencing drought. The feeding injury caused by these mites leaves white or brown spots that are referred to as stippling.