High levels of fungal disease like tar spot and southern rust are lurking in corn fields across the U.S. Midwest, threatening to reduce yields of a record-large crop and cause headaches for farmers during the autumn harvest.

Corn diseases lurk in bumper U.S. crop, threatening yields

Crop tour finds huge Minnesota, Iowa crops, but diseases lurk
Prospects for corn and soybean crops in Iowa and Minnesota are the strongest in at least 22 years, scouts on Pro Farmer’s annual tour of top grain-producing states said on Thursday, but diseases already lurking in fields could limit yields at harvest.

Crop tour finds strong corn, soy potential along with diseases in Illinois, western Iowa
Corn yield potential and soybean prospects are significantly above average across Illinois and western Iowa, though plant diseases could threaten final yields, scouts on an annual crop tour of the Midwest said on Wednesday.

Nebraska soy, Indiana corn show best potential in years, crop scouts say
Nebraska’s soybean pod count is the highest in at least 22 years, and its corn yield potential is the strongest in four years, scouts said on Tuesday during the second day of Pro Farmer’s annual tour of major grain-producing states.

Dry soils threaten strong Ohio crops; rains boost South Dakota — tour
The production potential of Ohio's corn crop is the highest in at least 22 years, scouts on the annual Pro Farmer tour of top U.S. producing states found on Monday, but dry conditions could limit yields by the time the autumn harvest rolls around.

U.S. grains: Corn, soy futures extend slide on milder weather forecasts
Chicago corn and soybean futures fell on Tuesday for a third straight session as forecasts for cooler Midwest temperatures this week and continued periodic rains reinforced expectations for ample U.S. harvests, analysts said.

U.S. grains: Corn futures hit two-week low; soy slides, wheat steadies
U.S. corn futures hit a two-week low on Monday and soybeans also fell as market players continued to brace for large crops and forecasts called for milder, non-threatening weather in the Midwest production belt.

U.S. grains: Soy futures end mixed; corn and wheat sag after USDA reports
Chicago Board of Trade soybean futures ended mixed on Monday, with nearby contracts under pressure after quarterly stocks data from the U.S. Department of Agriculture showed larger-than-expected supplies as of June 1, analysts said.

U.S. grains: Wheat surges four per cent on short-covering, lifting corn and soy
Benchmark Chicago Board of Trade wheat futures jumped more than four per cent on Wednesday as weather worries in parts of the United States and Europe, coupled with signs of fresh global export business, prompted speculators to cover short positions, brokers said.

U.S. grains: Soybeans end higher, supported by crude oil; wheat rises, corn mixed
Chicago Board of Trade soybean futures closed higher on Tuesday, supported by rising crude oil prices and uncertainty about Midwest crop weather in the weeks ahead, while soyoil prices eased following a sharp two-day rally tied to stronger U.S. biofuel blending mandates.