Plastic Culture Crops
Fumigants are used to suppress populations of parasitic nematodes, soilborne diseases (Rhizoctonia, Pythium, Fusarium) and weeds (nutsedge) beneath the plastic tarp.
Tomato, pepper, squash, cucumber, cantaloupe, watermelon and cabbage are grown in the Southeast in open fields on raised beds covered with plastic tarps. Production is dependent on the use of fumigants. Due to the climate, growers have the ability to produce multiple crops from a single fumigation and tarping. It is common practice for a grower to fumigate once in the spring for a pepper crop, which is followed by a summer cucurbit (squash, cucumber, cantaloupe, watermelon) crop and a late fall or winter cabbage crop before removing the plastic tarp to begin the next fumigation cycle. Tomato, pepper, cantaloupe and watermelon are usually the initial crop following fumigation. Squash, cucumber and cabbage are a second or third crop in the production cycle following fumigation.
Fumigants are applied to 93,000 acres of squash, pepper, cucumber, cantaloupe, watermelon, cabbage and tomato in southeastern states. Fumigants are applied two to four weeks before the crop is planted to avoid the risk of crop injury. A three-way fumigant system consisting of 1,3-D, Chloropicrin and Metam Sodium is increasingly being used in the southeast. The three-way mixture of fumigants has been shown to reduce the emergence of nutsedge plants; the most problematic weeds. Additionally, The population density of Pythium, Fusarium and Rhizoctonia in soil has been shown to be reduced by over 90% with fumigation and populations of nematodes have been reduced by 90% with fumigation treatments.*
Untreated: Yellow and purple nutsedge left untreated make it economically difficult to grow tomatoes due to over-population of the weed.
Treated: The crop in the treated photo clearly shows the reduction in weeds and the distinct growth in tomatoes.
Soil fumigation reduces the nutsedge population, Southern blight, and root nibblers. This allows plants to be grown cost-effectively with a higher yield.
"At a North Carolina research site with no nematode problems and relatively low nutsedge populations, tomato yields in the nonfumigated plots were still 20% lower than the fumigated plots."*
Untreated: Purple and Yellow nutsedge are the most troublesome weeds in the southeast. Without fumigation, weeds will emerge through the holes cut in the plastic used for transplant.
Treated: Funigation prevents the emergence of 93% of the nutsedge plants up to 81 days following plastic laying.
In experiments, the use of fumigants doubled pepper yields in comparison to the untreated crop. The number of marketable squash and cucumbers were doubled with fumigation treatment. Research has also shown that the yield of a second crop of cantaloupes was increased ten times as a result of fumigation of the first crop. The yield of a second crop of squash tripled as a result of fumigating the primary crop.*
*For a complete review of various results visit: Crop Protection Research Institute @ croplifefoundation.org