Cause Meloidogyne hapla, root-knot nematodes, are sedentary endoparasites, where only second-stage juveniles (infective stage) and adult males (may be rare) are in soil.
Symptoms During the growing season, knots develop on roots. Nematodes also can be found in tissue inside the corm above the basal plate. Necrotic areas may indicate their presence. The nematode's location below the corm surface makes it difficult to select nematode-free corms and can be a source of infestation of nematode-free soils and other host plants.
Sampling Take soil samples well before planting in order to implement management procedures if necessary. It may be several weeks before crops can be planted in fumigated soil. Fall sampling for crops to be planted the following spring is an excellent strategy. When sending samples for diagnosis, include roots as well as soil.
Cultural control
- Obtain planting stock from nematode-free nurseries.
Chemical control Preplant soil fumigation.
- Basamid G at 305 to 450 lb/A, depending on soil type, for an 8-inch incorporation. Drench with water and cover with plastic. Replant restrictions are based on soil temperature at 4 inches. See label for details. 5-day reentry. Restricted-use pesticide.
- Telone II Rates depend on planting depth and soil type; see label for details. 5-day reentry. Restricted-use pesticide.
Reference Overman, A.J. 1970. Gladiolus corm dips for root-knot nematode control. In Proceedings of the Florida State Horticultural Society. 82:362-366.