WEST LAFAYETTE, Ind. — According to Purdue University extension corn specialist Bob Nielsen, moderate temperatures to this point have helped the Indiana crop. Some educators participating in a Purdue conference call last week commented that cool overnight temperatures – encouraged by the low humidity and clear skies – also have helped.

“My thoughts in the past week or so have been that corn has been hanging in there pretty well,” Nielsen said. “There are some truly, severely stressed parts of the state, but in the state as a whole, corn has hung in there amazingly well. But I have in the back of my head that I think we’re on the brink of something serious.”

He said if growers don’t start getting widespread rain in coming weeks, they’re looking at a repeat of the drought of 1988. That said, he added there’s still hope if rains arrive in a timely fashion. He said 2007 also was a dry year, but yields were reasonably decent.

The corn crop can lose much yield potential if field conditions are droughty at pollination, and Nielsen said the crop is moving into that critical pollination stage earlier since it was planted earlier.

“Most corn pollinates in early July,” he explained. “This year it’s going to be a week or more earlier. In a normal year, that’s good because it’s missing the July heat. This year is different because of early hot temperatures. The last week of June to mid-July is when most pollination will occur. That will be the critical window.

“Then we’ve got to get through grain fill, but that’s a whole other story.”

In a press release, University of Illinois crop sciences professor Emerson Nafziger noted crops in the Land of Lincoln also are feeling the drought. He explained inhibited plant growth is resulting from slowed photosynthesis.

In corn, he said, when leaves are rolled during the day and out during the cooler night periods it means slower photosynthesis rates. Corn planted in dry fields or later in the season, he continued, will be smaller and, if dry weather continues, silks and kernels also will be small, affecting yield.

Floppy corn is another problem Illinois farmers are seeing, according to Nafziger. One cause, he said, is poorly developed nodal roots, when the root system is unable to tap into soil moisture.

Some of the Indiana extension educators reported both corn and soybeans in their counties are in a holding pattern, having stalled out awaiting rain. Corn leaves are curled and bean leaves are cupped in defensive postures, and little is happening in hayfields after the first cutting, they said.

“The plants are just kind of sitting there,” said Purdue extension soybean specialist Shawn Casteel. “Most plants put more energy into root development instead of leaf development in these types of conditions. That’s where plants are now.”

Illinois soybean growers are seeing the same stall pattern in their fields.

“Leaves don’t roll in soybeans as they do in corn, but instead tend to lose turgor and droop, in some cases dropping to vertical orientation,” Nafziger said.

“This helps them avoid sunlight and the heating that comes with it when there’s not enough water to keep photosynthesis going. But it also means they’re doing no photosynthesis, which means they’re not growing.”

Casteel said some fields are “pretty pathetic in terms of emergence.” Nafziger said there are poor stands in Illinois as well. Unemerged seeds that received limited moisture and need to break through the dry soil surface are the ones that will struggle, according to Casteel. A lot of seeds didn’t get any moisture and will simply sit in the field.

“In general, the ones already up are not looking that bad,” he said, adding those plants will maintain their roots and the moisture in the plant, but will put out fewer nodes. “Beans have the ability to compensate, even with fewer nodes. If it rains in July and August, we can make up a lot of ground in beans. Soybeans have a longer window of how they can handle drought conditions.”

Mites could be an issue in soybean fields this year, according to Purdue extension entomologist Christian Krupke. “Mites are in our fields all the time every year, but we don’t think much about them because they don’t do damage,” he said. “In a dry year it’s different.”

He urged growers to be vigilant and watch bean field edges, where mites will appear first. He said catching them early is critical.

“Bronzing of leaves is diagnostic,” Krupke said.

To scout for the mites, he suggested holding a white paper or handkerchief under the plant, then tapping the plant. He said the mites will fall and show as small, black moving dots against the white. If mites are present, he said, field borders can be treated with Lorsban. He said there’s some advantage to treating green areas along with bronzed areas.

“Yield loss could be huge, off the charts, if they’re untreated,” Krupke said. “Mites will kill everything. Mites are one of the ones where, if you let mites go and conditions are right, mites can be devastating. Fortunately, we have products that work, so that doesn’t have to happen.

“Rain will cure mite woes literally overnight.”