BATON ROUGE — Unusual cold snaps during this growing season are affecting tomato crops throughout Louisiana, said LSU AgCenter Plant Doctor Raj Singh.

Young, actively growing tomato seedlings are highly prone to cooler temperature injury. Injury on the leaves appears as sunken, tan-colored spots. Spots may turn purplish brown over time. These spots are present between the veins on the leaves.

Plants show symptoms in a few days after being exposed to cold temperatures, Singh said.

Damage appears uniform on all exposed plants and may occur on several different varieties.

Severely affected plants may not fully recover from the injury, resulting in reduced plant growth and fruit production.

Injury on the leaves cannot be reversed. Damaged older leaves may be removed a few weeks after the plants starts to grow actively again.

“The best way to avoid cold injury to your tomatoes is to protect them during cold weather,” Singh said. “There are a variety of frost covers available to protect plants from cooler temperatures, including blankets, fabric sheets, plastics and tarps.”

Growers must remember to remove the covers as soon as the temperature returns to normal during the day to prevent excessive heat buildup.

Containerized tomato plants can be moved inside to protect them from cold, but move them outside as soon as the cold spell is over, Singh said.