- Worldwide distribution. In tropics and sub-tropics. Several types. On many vegetables (beans (see Fact Sheet no. 127), capsicum, carrot, celery (see Fact Sheet no. 254), cucumber, eggplant, ginger, lettuce, potato, tomato and yam), fruit crops (melon, papaya, pineapple), ornamentals, and weeds. Important pests.
- Plants become yellow, stunted, and wilt. Characteristic galls on the roots ('knots').
- Eggs laid in soil, worm-like young females enter the roots to feed and lay eggs, causing cells to swell.
- Spread occurs in soil water, on tools, footwear and machinery, and over long distances in plant roots, especially in the trade in vegetable seedlings and ornamentals.
- Cultural control: resistant varieties; pasteurised soil or use soilless mixes; crop rotation; fallow periods (4-6 months); soil solarisation (4-6 weeks); manures and composts; marigold fallows.
- Chemical control: none recommended.
Pacific Pests, Pathogens, Weeds & Pesticides
Root knot nematodes (127)
Photo 2. As in Photo 1, galls of Meloidogyne sp. on Phaseolus bean. Note the galls on the roots of the two plants on the left with smaller root mass compared to the healthy plant on the right.
Meloidogyne incognita and other species.
AUTHOR Grahame Jackson
Information from CABI (2014) Meloidogyne incognita (root-knot nematode). Invasive Species Comperndium. (https://www.cabi.org/isc/datasheet/33245/); and information (and Photo 4) from Diseases of vegetable crops in Australia (2010). Editors, Denis Persley, et al. CSIRO Publishing. and information (and Photos 1&2) Gerlach WWP (1988) Plant diseases of Western Samoa. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany.
Photo 2 John Bridge, Tropical Plant Nematology Advisor, CABI Bioscience, Egham, UK. Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community.