Off-season Plant-parasitic Nematode Management for Vegetables through Biofumigant Cover Crops

View the project final report

Commodities

• Agronomic: mustard, radish (oilseed, daikon, forage), rye
• Vegetables: cabbages, tomatoes

Practices

• Crop Production: cover crops
• Pest Management: biofumigation

Georgia has a vital role in the national vegetable production with a farm gate value of $1.14 billion (Wolfe and Stubbs, 2016). The state is a leading producer of fresh market vegetables including cucurbits, brassicas, bell peppers, onions, sweet corn, and tomato. In Georgia, more than 66% of vegetable growing areas are infested with at least one species of root-knot nematodes (Meloidogyne spp.) at the level of one nematode per 100 cm³ of soil where management is needed to achieve economically reasonable yields (Marquez et al., 2021). The nematodes most associated with vegetable production in Georgia are three species of M. incognita, M. arenaria, and M. javanica that cause severe yield loss particularly in small-scale farms that may not have the resources necessary to utilize fumigants (Marquez et al., 2019).

The phase-out of methyl bromide has caused a void in vegetable production that forces growers to use new fumigants and non-fumigants nematicides to control nematodes. However, new regulations regarding the application of fumigants, the difficulty of application, and the high costs of fumigants are compelling growers to use sustainable and environmentally friendly yet effective options for PPN control. In southern Georgia, despite long growing seasons, the practice of growing two vegetable crops on the same agricultural land often creates a narrow window for growers to use cover crops. Hamid and Hajihassani (2020) evaluated several cultivars of oilseed radish (Carwoodi, Cardinal, Final, Image, Concorde, Control, Eco-Till, Karakter, and Cannavaro), white (Tachiibuki), and black (Pratex) oats. They reported that the Control and Carwoodi radish and Tachiibuki oat were resistant to M. incognita. Field research conducted in Georgia reported an increase in M. incognita population levels in the rhizosphere of some Brassica species, but the incorporation of the crop residues into soil suppressed the nematode (Monfort et al., 2007). Nematode management can be improved by gaining more information on nematode population changes as influenced by nematode-suppressive cover crops and the efficacy of non-fumigant nematicides on cash crops grown after cover cropping. 

The objectives of this project were to determine the suppressive effect of oilseed radish, white mustard, cereal rye, and oats on root-knot and stubby-root nematode populations and to evaluate the subsequent damage caused by these nematodes to cabbage grown after cover crops and treated with a non-fumigant nematicide, fluensulfone.