Published on 09/17/01

Rains Boost Crop Yields, Prod Diseases

In most cases, the weather has helped Georgia farmers' crops this year. But it's also helped plant-threatening diseases thrive in many Georgia fields, says a University of Georgia expert.

"It's been one of those years where conditions that are good for crops have also been favorable for diseases," said Bob Kemerait, a UGA Extension Service plant pathologist.

Crops enjoy the weather

Though isolated sections of the state still struggled with dry weather, increased rainfall improved soil moisture in most sections and eased the state out of the drought of the past few years.

As of Sept. 9, Georgia Agricultural Statistics Service reported that two of Georgia's top row crops are enjoying the weather. About 89 percent of the cotton is in good to excellent condition, as is 95 percent of the peanut crop.

Colquitt County farmer Randy Buckner said he's much happier with his peanut and cotton crops. The part he didn't irrigate looks as good as the part he did in many places. This means a sharp improvement in rainfall, he said.

"Overall, we're looking pretty good with the peanuts and cotton," Buckner said. "I expect we'll do pretty good on yields."

Diseases enjoy weather, too

Row crops like hot, humid weather and moist soil, something Georgia has had more of this year. In this condition, crops grow full, healthy plant canopies.

Ironically, the environments under these canopies provide the perfect conditions for diseases to grow and infect the plant, Kemerait said.

Early in the season, Fusarium wilt caused problems in a few cotton fields.

"The fungus invades the roots and the lower stems and plugs up the plant's vascular tissue, inhibiting the normal flow of water and nutrients in the plant," Kemerait said.

The biggest problem with cotton right now is rotting of bolls, the fruit that produces the lint.

"I've been in fields where an entire bottom crop is lost," Kemerait said.

Wet weather, such as that brought on by tropical storms this season, came as bolls entered a critical growth stage. Thick plant growth, again, kept moisture and humidity levels high under canopies. This allowed rot to establish on the bolls and reduce yields, he said.

Cooler, wetter conditions in June may be related to an unusually high number of outbreaks of Cylindrocladium black rot (CBR) in peanuts.

This disease can destroy any part of the plant below the ground, Kemerait said. Historically, CBR has been of greater concern in peanut production areas north of Georgia, such as Virginia and North Carolina.

"It's been showing up in a lot of fields where it wasn't expected," he said. "Many growers who thought they didn't have a problem have had a problem this season."

Using good management practices, Georgia farmers were able to fight many diseases that threatened their crops.

But if the favorable weather continues, Kemerait said, farmers will have to stay on top of new and more cost-effective ways to handle the disease pressure that follows.

Good yields

Overall, the peanut and cotton crops should produce good yields, Kemerait said.

Buckner agreed. Despite the disease pressure, he said, he'd take the increase in moisture any time.

The GASS report forecast Georgia's 2001 cotton crop to average 680 pounds of lint per harvested acre, or 89 pounds more than in 2000. Acreage expected to be harvested this fall is estimated at 1,490,000 acres, up 140,000 acres from last year.

Yields across the Georgia peanut belt are expected to average 2,800 pounds per acre, compared with 2,700 for 2000. Harvested acres are expected to be 477,000, down from 492,000 in 2000.

Brad Haire is the former news editor with the University of Georgia College of Agricultural and Environmental Sciences.