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First Report of Root-Knot Nematodes (Meloidogyne spp.) on Sunflowers in Mozambique

Sunflower (Helianthus annuus L.) recently was reintroduced to Mozambique because of renewed interest in oil-seed production for domestic consumption. In April 1997, disease surveys were carried out in two fields in southern Mozambique (Maputo region). Several plants of Pan 735, a South African cultivar, showed yellowing of the leaves and stunting. These plants wilted during the day but recovered their turgidity at night. Diseased plants were easily pulled from the soil due to almost complete destruction of the root system. Numerous galls were found on affected roots, compared with healthy plants. Meloidogyne javanica (Treub) Chitwood and M. incognita (Kofoid & White) Chitwood were identified by M. Di Vito (personal communication) based on 20 female perineal patterns observed with a light microscope. M. incognita was more prevalent than M. javanica. Also observed were Alternaria helianthi (Hansf.) Tubaki & Nishihara and Sclerotium bataticola Taub. Root-knot nematodes (Meloidogyne spp.), common on sunflower, cause severe damage and reduce both seed yield and seed oil content (1). These two nematode species have also been observed on sunflower in other African countries (Zambia, South Africa, Egypt) but this is the first report of root-knot nematode on sunflower in Mozambique.

Reference: (1) M. Di Vito et al. Nematol. Medit. 24:109, 1996.