Plant breeders with the Agricultural Research Service have developed two bell pepper cultivars that resist the rootknot nematode, a pest responsible for more than $150 billion in losses annually worldwide.


In the past, growers used methyl bromide to control the soil-borne pest, but the fumigant's use is being phased out.


Judy Thies, with the U.S. Vegetable Laboratory in Charleston, N.C., led the team that developed and tested the varieties Charleston Belle and Carolina Wonder, according to a paper published in HortScience magazine.


In trials in Citra, Fla., she compared to two candidates with their susceptible parents, Keystone Resistant Giant and Yolo Wonder B.


In the fall test, Charleston Belle and Carolina Wonder exhibited minimal root galling and nematode reproduction whereas Keystone Resistant Giant and Yolo Wonder B had severe root galling and high nematode reproduction.


Charleston Belle yielded 97 percent more fruit than the susceptible cultivars.


In the spring test, one-half of the plots was treated with methyl bromide and chloropicrin before planting the same four bell pepper cultivars.


Keystone Resistant Giant and Yolo Wonder B grown in untreated control plots exhibited severe root galling and high nematode reproduction. But the other six treatments showed minimal root galling and nematode reproduction.


Although soil temperatures 10 centimeters deep were more than 86 degrees Fahrenheit on 78 days during the fall trials and 57 days during the spring trials, the resistance did not break in Charleston Belle or Carolina Wonder.

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