Loose Smut - Management

Management

The most widely used method of control for loose smut is using treated seed. Seeds are typically treated with a systemic fungicide to kill any fungus that may be inside. Since the fungus grows up with the plant, it's very important that the fungicide used to treat the seed be systemic and not just external. The most common type of systemic fungicides used for loose smut are from the Carboxin group of chemicals. Although carboxins are highly toxic to fish and mildly toxic to other animals, they degrade rapidly in the environment and since there the fungicide is coated on seed and not sprayed there is not much loss to the environment.

Barley varieties with resistance to loose smut are also commercially available. Although gene marker technology is being researched and used to help speed the process of resistant variety development, these traditional breeding methods are still very slow, and it is difficult to develop varieties with resistance which also possess other desirable traits such as those for yield and grain quality.

Recent studies have also investigated the use of foliar-applied systemic fungicides, particularly the fungicide triadimefon, for treatment once infected seeds have already been planted. Applying before the flag leaf stage significantly increased the amount of heads which were only partially smutted and also significantly increased yield. However the foliar-applied method is more expensive, more labor intensive, and less effective than simply treating the seed before planting. Buying treated seed from a certified seed company will significantly reduce the chance of seeing loose smut on a crop.

Another option is heat treating the seed to kill the fungus before planting, but this is a delicate process because too much heat will kill the plant embryo and not enough will allow the fungus to survive. Research has also been done to use radio frequency heating to treat seed. Seeds are run on a conveyor belt between two electrodes which create an electromagnetic field between them and allowed for controlled temperatures.