CARBONDALE, Ill. — Tropical Depression Isaac left a good, bad and potentially ugly impact on farmers in Illinois.

On the good side, the former hurricane that slammed the Gulf Coast in late August dumped in some areas of Illinois about 7 inches of rain during a 24-hour period beginning Sept. 1. The deluge helped restock ponds and wells that had gone bone-dry from this season’s drought, saving farmers and ranchers at least a few weeks’ worth of water hauling costs.

The National Weather Service (NWS) in Paducah, Ky., reported that Centralia, in south-central Illinois, received the highest accumulation of rain at 7.8 inches. Rainfall totals varied in other areas, from 5 inches at Carlyle Lake and 6.8 inches in Greenville. In some locations, several inches fell in a short period of time.

“The storm wasn’t really very well-organized,” said Jayson Wilson, an NWS meteorologist based in Paducah. “While there may have been widespread rain, those who got thunderstorms got torrential rain.”

Kenneth Metcalf, a rancher with 160 head of cattle just east of Springfield, said he appreciated the extra water. He said he uses about 300-400 gallons a day for his cattle – water that he has had trucked in for the past six weeks.

“I think everybody feels better from this rain. We’ve needed it a long time, but I wouldn’t be surprised if we’re hauling water again sometime soon,” Metcalf said.

The bad is that Isaac’s water really didn’t do much good for what corn is left, although some late-planted soybeans and winter wheat fields could see a small benefit, according to a USDA report last week.

And the deluge in some parts was untimely for whatever corn farmers can get out of the field, delaying for days any potential at harvesting. High winds from the storm damaged some corn still standing because of drought-weakened stalks.

Mike Campbell started the Thursday before Isaac hit, and he said he’s lucky if he gets 30 bushels per acre on his 400-acre corn tract near Edwardsville. He said he’s usually at about 150 bushels per acre. Some of his corn was wind-damaged after Isaac hit.

“When I was first harvesting, before the storm, it sounded like the combine was shut off, there was just so little stuff going through it,” he said. “It’s the worst I’ve ever seen.”

The potentially ugly part? Experts say the heavy rainfall could pose serious risks to vegetable growers, including outbreaks of downy mildew of basil, downy mildew of cucurbits and Phytophthora blight of cucurbits and peppers.

“These diseases are caused by oomycete pathogens,” said University of Illinois crop scientist Mohammad Babadoost. “The excessive moisture in the soil due to the recent rainfall makes conditions perfect for these pathogens to spread.”

Downy mildew of basil is new in Illinois, first detected in 2009, Babadoost said, and can cause total crop loss quickly. It can be controlled by applying fungicides such as mandipropamid alternated with azoxystrobin or cyazofamid on a weekly basis.

Downy mildew can impact all cucumber and melon crops. Babadoost said mandipropamid (Revus), propamocarb (Previcur Flex), dimethomorph (Forum), famoxadone + cymoxanil (Tanos), cyazofamid (Ranman), fluopicolide (Presidio) and zaxomide + mancozeb (Gavel) are effective against downy mildew.

Phytophthora blight is one of the worst diseases of cucurbits and peppers in Illinois, he said, and the infection first appears in low areas of fields were it remains wet the most. Again, fungicides are the remedy: mefenoxam (Ridomil Gold), Mandipropamid (Revus) and cyazofamid (Ranman).