Hurricane Gustav dumped 18 inches of rain on Ken Thornhill’s sweet potato fields in Franklin Parish, La. Hurricane Ike didn’t hit his fields as hard, but sweet potato growers across Louisiana are reeling from the two storms.

“It’s really a sad period for Louisiana’s sweet potato industry,” Thornhill said. ”In Louisiana, sweet potatoes have been the leading vegetable industry for well over 100 years. We don’t know what we’re going to have after this. It’s going to be greatly reduced.”

According to early estimates from LSU AgCenter economists, the state will lose 50 percent of its crop. The excessive water is causing the potatoes to rot in the field.

LSU AgCenter sweet potato specialist Tara Smith said the flooding has led to prolonged saturated conditions. “Basically, sweet potatoes are living, breathing organisms,” Smith said. “And under those saturated conditions when oxygen is excluded from the soil, they’ll start to breakdown.”

The 2008 crop was shaping up to be an excellent one, with high-quality potatoes and above-average yields. Now as farmers harvest, it’s not unusual to pull a bushel of potential No. 1 grade potatoes that have already started to deteriorate, Thornhill said.

The outlook could become worse after the sweet potatoes are harvested and stored. “The manner in which sweet potatoes are harvested with all the hands that have to come in contact with the sweet potato in the field, it’s impossible to cull out all the damage,” Smith said. “So we realize that we will see some significant breakdown in storage houses across the state.”

Complications from the storms will linger into next year’s planting season. Growers produce their own seed potatoes each year, and many of those fields are in poor condition.

“With the conditions we are experiencing, it is very probable that a portion of our seed potatoes will go unharvested this year or the quality of those seeds will not be as good as it should be,” Smith said. This could have farmers scrambling to find seed potatoes to purchase in the spring.

Despite this blow, Smith is optimistic the industry can recover. “If we stay in this weather pattern — a lot of wind and cooler weather — conditions are favorable for harvest, and we’ll understand more of what’s going on in the fields,” Smith said.

Louisiana has 16,000 acres of sweet potatoes. Ninety percent of the acreage was affected by the hurricanes, Smith said.

Kurt Guidry, LSU AgCenter economist, said the estimated revenue loss for sweet potato growers because of Gustav was $33.5 million.

e-mail: tblanchard@agcenter.lsu.edu