News Release Distributed 03/20/14

BATON ROUGE, La. – Commercial greenhouse vegetable production is becoming increasingly popular in Louisiana. While there are benefits to local production, even small-scale growers must learn how to prevent and manage diseases.

LSU AgCenter plant pathologist Melanie Lewis Ivey is studying how diseases enter greenhouses and cost-effective prevention methods. The project is a collaboration with Ohio State University and is funded by a $2 million specialty grant from U.S. Department of Agriculture’s National Institute of Food and Agriculture. The AgCenter’s part is $130,000.

Ivey said the goal is to identify the entry points of high-risk pathogens and develop best practices for safeguarding greenhouse crops from bacteria, viruses and viroids. She also hopes to find out if plant pathogens and human pathogens enter systems at similar points.

Ivey said the project includes both small and large greenhouses, so researchers can determine how risk levels vary by size of the operation.

So far, researchers have identified listeria and salmonella in the greenhouses. Outbreaks of these bacteria can make people sick and prompt recalls that have a significant impact on the food industry.

In 2013, the total value of greenhouse tomato production in Louisiana was more than $2.4 million, according to the AgCenter’s Ag Summary.

"The greenhouse industry has really picked up, especially in the United States," Ivey said. "That has a lot to do with consumer interest in locally grown produce as well as you can make quite a bit of money growing greenhouse tomatoes. There's a high profit range."

Implementing changes that make produce safer can be costly, so some growers choose to take risks. Larger operations that sell globally tend to have more safety precautions in place because they must deal with international regulations, Ivey said. Even in those situations, however, compliance can be difficult.

Because food safety is ultimately up to the people who grow and process food, Ivey is assembling a guide that will help greenhouse producers learn about best practices for plant disease and food safety management.

Buying clean seed and growing disease-resistant varieties can minimize outbreaks. Sanitation is also important — workers should keep equipment clean to avoid spreading pathogens when pruning or harvesting, Ivey said. Good personal hygiene helps prevent the spread of human pathogens.

Water is another key issue in dealing with disease. Ivey said growers who recycle water should treat it before reintroducing it to plants. Surface water should also be treated to eliminate plant and human pathogens.

Olivia McClure