Fungal infections in seed are not normally a problem under the High Plains' dry weather conditions, but they can still occur, a Texas AgriLife Extension Service specialist said.
Both producers and grain elevator operators need to be vigilant in their watch for contaminated seed and make sure treatment occurs before the seed from one year's harvest is replanted the following year, said Dr. Ron French, AgriLife Extension plant pathologist.
French spoke at the Texas High Plains Grain Elevator Workshop in Amarillo. He told the elevator operators seed quality remains one of the top issues in stored grains as it relates to seedling diseases and future diseases wheat might face if the grain is used for planting.
There are several fungi that can attack cereal grains, he said. Some of these fungi can cause black point (kernel smudge), stinking smut (common bunt), and other secondary rots which can slowly degrade grain seed if improperly stored.
The seed can be infected with the fungi pre-harvest if the crop was subjected to stresses such as drought, insect damage, moisture, wind damage and other conditions that favor plant disease development, French said.
“Even if seed is properly cleaned, some affected seed might escape the cleaning process.”
Seed containing certain fungi can suffer from damping-off, root or crown rot at the seedling stage, French said. Some fungi can become a problem later in the season if the seedling survived.
“Several fungi can cause such rots, but they also can be managed with seed treatments. If you've had a history of soil-borne pathogens in your field, such treatment might be warranted.”
Fungi also may become a problem in storage facilities with a history of seed contamination and/or if the storage unit had not been properly cleaned, French said. The right temperature and moisture conditions must be maintained in grain elevators to prevent fungi from being active against the seeds.
“Under the right conditions, fungal spores can germinate and infect seed during storage, causing moldy or rotted seeds,” he said. But generally there are few fungal problems seen at the elevator level.
In addition to affecting the performance of the crop, the fungi are a concern because some can produce toxins that affect both humans and animals, French said. Good seed quality and storage conditions are important in preventing such toxins from occurring at unacceptable thresholds.
“The healthier the crop, the less chance for it to be susceptible to fungal pathogens and their byproducts,” he said. “If you are a producer who had problems with sooty molds, stinking smut, black point, kernel rots and other seed rots, you probably should use a fungicide seed treatment before using that seed again.
“If you are worried about your own seed quality, you also might want to look into the possibility of purchasing certified seed,” French said.