PITTSBURG — The unusually wet weather in Southeast Kansas this year has caused a variety of problems — from storm damage to increased numbers of mosquitoes. For area farmers, there may be a growing concern of increased crop disease and pest issues.
A recent report from Kansas State University Research and Extension notes that southern rust has been detected on corn in the state, including a positive identification in Labette County.
“The first positive field in 2019 was discovered on July 11, but based on the age of the pustules, it has been here since sometime in mid-June,” the report notes. “This, combined with very late-planted corn in many areas of the state, increases the threat that this disease will cause significant yield loss problems in 2019.”
Wildcat Extension District Crops & Soils Agent James Coover said in a recent interview that while southern rust can probably be found in the area every year, and may already be affecting corn in Crawford County and simply not have been officially reported or detected yet, it is usually not found until August, when the crop is mostly done.
He added that in a typical year corn would also have been planted earlier, and current conditions could result in yield damage from southern rust. 90 degree days and humid nights are about the best conditions for southern rust, he said.
“It has a higher chance of infection,” Coover said, “so that’s why there’s an increased concern this year.”
Coover also said area farmers may need to spray fungicide right before or during corn tasseling to mitigate effects of gray leaf spot, which could also provide some extra protection for southern rust. Common rust may also be present on corn in the area, but is not as serious of a concern as southern rust or gray leaf spot, Coover said.
There are a total of six or more different fungal diseases that can affect corn, Coover said. For soybeans, fungal diseases are “a whole different ball game,” Coover said, but he has no major concerns about specific soybean fungal infections that present an increased risk this year because of weather conditions or planting times. None of the fungal diseases are transferable between corn and soybeans.
Pests are also a potential problem for farmers. Thistle caterpillars and webworms as well as bean leaf beetles are some varieties that have been cause for concern this year, Coover said, and spider mites could be an increased problem as the weather gets hotter.
Thistle caterpillars in particular have been found in recent weeks, but haven’t generally been building up in large enough numbers to cause economic damage, Coover said. Another generation of all of the varieties of pests he mentioned could come back in the near future and cause problems, he added, although pests are a little harder to predict than fungal diseases based strictly on weather conditions.
“With the funguses, that’s definitely a component of the weather,” Coover said, and “it’s kind of been the perfect year” for those problems.