A fungal disease common to greenhouse tomatoes has shown up in many Louisiana greenhouses, thanks to cool, wet and overcast conditions.
Gray mold, caused by botrytis cinerea, develops readily during periods of high humidity and cool to moderate temperatures, according to a news release.
“Recent episodes of cool, wet weather with overcast conditions may have been a contributing factor in the outbreak of gray mold in Louisiana,” Raghuwinder Singh, Lousiana State University AgCenter plant diagnostician, said in the release.
It has been found in greenhouses from East Feliciana to Terrebonne parishes.
The disease hadn't been seen for six years in St. Charles Parish and for three years in Terrebonne Parish.
The pathogen produces spores and white to gray fungal growth on plant parts.
The spores resemble clusters of grapes on branched fungal stalks.
They can become easily airborne and spread throughout a protected facility.
The spores also can be spread on clothing of workers who come in contact with infected plants.
Gray mold can be managed through cultural and chemical practices.
Inoculum levels can be reduced by removing plant debris, sanitizing the greenhouse before and after each cropping season, and scoutting plants regularly to catch infections early.
Apply fungicides preventatively during favorable environmental conditions, including cool, wet weather with overcast conditions, according to the news release.