Area fields faring mostly well
WORTHINGTON -- The Independence Day holiday has long been used as a gauge in crop development, but the old adage of knee-high by the Fourth of July seems rather outdated.
Actually, this year's corn crop is hip-high to waist-high in most area fields.
There are spots, however, where the crops aren't looking as well, particularly in fields damaged by high winds and hail -- more prevalent in west-central and southeast Minnesota, as well as in northwest Iowa. Fields in the path of last weekend's tornadoes in Lyon and Osceola counties were virtually wiped out.
"So far, areas where we haven't been hit by severe weather ... overall crop conditions look really well," said Liz Stahl, crops specialist at the University of Minnesota Extension Regional Center in Worthington. "We're certainly ahead of where we were last year."
While it's too early to be making predictions about a bumper crop, Stahl said, "I think we're set up really well this year with early planting dates. Hopefully we'll continue to have decent temperatures and adequate moisture."
Moisture is issue
With southwest Minnesota's winds, combined with more significant rains, Stahl said farmers have been challenged to get herbicide on their crops in a timely manner. As such, some fields have a lot of weed development, which can ultimately impact yield.
"This is one of those years where you can really tell if someone didn't have a pre-emergence herbicide down," said Stahl. "If you can't tell where the rows are, you're definitely losing yield."
For farmers still looking to apply herbicide, Stahl cautions them to follow product labels. Many have restrictions not to apply during soybean flowering stage because it could result in pod abortion.
Not only has rain prevented farmers from getting out and spraying their crops, it's also led to some reports of yellowing in corn, which is a sign of nitrogen deficiency.
"We don't want to have moisture stress at this time," said Stahl, adding that plants are moving into a key period of development. Soybeans are starting to flower, and corn is on the verge of tassling.
"We need to continue to get adequate moisture -- especially during pollination," she said.
According to the weekly crop weather report issued by the U.S. Department of Agriculture's National Agriculture Statistics Service earlier this week, Worthington is nearly 2 inches above normal in precipitation. Also according to the report, Worthington has logged 873 growing degree days between April 23 and June 27, which is 56 growing degree days above average.
Continue to scout
As we move into mid- and late-July, Stahl said farmers should be scouting their fields for soybean aphids, a pest that feeds on plants and can have a tremendous impact on yield.
"I really encourage people to not pull the trigger too fast," said Stahl in regard to spraying for the miniature pests. "Much of the work on thresholds has been done in Minnesota and much of that research pertains to us. It pays to use those economic thresholds."
The threshold for aphid spraying is 250 aphids per plant, with aphids on at least 80 percent of the plants and increasing.
"Spraying aphids in late June and early July are just a bad idea," she said, adding that products have a residual, at most, of 14 days, and any new plant tissue will not be protected.
Soybean Cyst Nematode populations should also be watched. Stahl said researchers are beginning to see SCN populations reproduce in what were SCN-resistant soybean varieties.
"If you've got a situation, we need to do something else to mix things up," she added.