Cold snap causes damage but has some benefits for farmers, too

BATON ROUGE, La. – Louisiana is experiencing record cold weather, with lows forecast to dip into the upper 10s and lower 20s across the state. While the freezing temperatures will negatively affect some agriculture operations, farmers may also see some benefits.

LSU AgCenter economist Kurt Guidry said because it is not growing season for any of Louisiana's major crops, the cold weather's advantages could outweigh its negative effects. However, there is concern about crops still in the field, particularly sugarcane.

Cold weather can kill sugarcane causing lower sugar content. Fortunately, most of this year's sugarcane crop has already been harvested, and the rest will be in by the end of this week, said LSU AgCenter sugarcane specialist Kenneth Gravois.

The quality of sugarcane remaining in the field probably will not suffer, Gravois said. Processing it, however, may be problematic.

"The biggest impact there will be trying to process frozen cane," he said. "You can't extract juice out of a stalk that's frozen."

This year's sugarcane crop has been good despite freezes in March that delayed the planting season, Gravois said. September and October were warm, allowing an extra two months of growth. Gravois said this may be the second- or third-best crop on record.

Gravois said this week's frigid temperatures will have little effect on the 2014 crop. Sugarcane prices remain low, which is probably more worrisome to growers than the cold weather, he said.

Wheat is also growing now, but Guidry noted it can withstand colder temperatures because it is a cool weather crop. The past few winters in Louisiana have been relatively mild, so this year's colder weather could mean wheat will stay dormant longer than usual, delaying harvests.

"Any time the crop is in the field for a longer period of time, it does bring the potential for more issues, whether it be insects or disease or weather," Guidry said.

Fruit and vegetable producers should harvest mature crops to avoid freeze damage and insulate plants that are still growing. Vegetables such as cabbage and broccoli can survive the cold weather, but other crops are less resistant, said Plaquemines Parish extension agent Alan Vaughn.

Citrus trees are usually unharmed if the temperature remains above 19 degrees, Vaughn said. Citrus fruit, however, is damaged if the temperature stays below 25 degrees for an extended period. Most of Louisiana's commercial citrus crop has been harvested already, he said, but growers are picking and storing what is left to avoid losses.

On the bright side, farmers may face fewer incidents of disease this spring. Guidry said freezing temperatures can lower the population of pathogens and reduce disease as host plants die from cold temperatures.

LSU AgCenter entomologist Michael Stout said the freezing temperatures could also mean fewer insects in the spring. The downside is that both pest and beneficial insects are at risk, he said.

However, most insects spend the winter in protected places — often under leaf litter or grasses — and are never completely exposed to the cold. Plus, "a lot of insects have adaptations for withstanding freezing temperatures," Stout said. For example, some insects keep warm by slowing their activity down or even by producing a substance that lowers their freezing point.

Dearl Sanders, coordinator of the Bob R. Jones-Idlewild Research Station in Clinton, La., said the cold temperatures will kill weevils that have been released to eat the giant salvinia plants clogging Louisiana waterways. The weevils cannot tolerate extended freezes — and in northern Louisiana, where temperatures could fall as low as 17 degrees, all of the weevils released since 2012 could die.

It takes at least three years of weevil reproduction to reach levels that control giant salvinia, Sanders said.

Although this week's freezes will kill about 90 percent of giant salvinia plants, Sanders pointed out that the surviving 10 percent is more than enough to keep the infestation going.