NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati Root-knot Disease of Solanaceous Vegetables Common Name: Root-knot nematode Scientific Name: Meloidogyne incognita, M. javanica Host Crops: Tomato, brinjal, chilli Distribution: Throughout country Symptoms: • Stunted growth in patches • Yellowing of leaves • Galling on roots Interaction with other organisms: Infection of root-knot nematodes predisposes healthy plants to many soil-borne pathogens like fungi, bacteria and viruses. Most common problem is breakdown of disease resistance and wilting of plants; bacterial wilt caused by Ralstonia solanacearum and fungal wilt by Rhizoctonia solani are frequently encountered in solanaceous crops (brinjal, tomato, chilli etc.). Biology and Life cycle: Soil-borne, sedentary endoparasite. Second-stage juveniles infect the roots of seedlings in nursery itself or after transplanting. The nematode develops endoparasitically feeding on the vascular tissues. Adult females are sac-like, vermiform males leave the roots and come out in soil. Females lay eggs in masses on root surface on galls, or in advanced stages inside the compound galls. Life cycle is completed within 25-30 days during summer months; in winter it may be prolonged to 60-90 days under north Indian conditions. Dissemination: Through infected seedlings Losses: 10-50% Management options: • Deep summer ploughing of nematode infested fields 2-3 times at 10-15 days’ interval 1|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati • Solarization of nursery beds with 25 μm clear plastic film for 15 days during May/June • Apply carbofuran (3G) @ 10 g/m2 in the nursery beds prior to sowing and neem cake @ 500 kg/ha 10 days before transplanting in the field • Use nematode-free transplants and raise nursery in root-knot nematode-free soil • Grow root-knot nematode resistant variety Hisar Lalit, Punjab NR 7 or SL 120 of tomato and Pusa Jwala of chilli • Seedling root dip treatment with carbosulfan (25EC) @ 0.05% for 30 minutes for tomato • Nursery bed treatment with either Trichoderma viride formulation (FYM incubated) @ 2.5 g/m2 or Pseudomonas fluorescens formulation @ 20 g/m2 2|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati Root-knot Disease of Okra Common Name: Root-knot nematode Scientific Name: Meloidogyne incognita, M. javanica Host Crops: Polyphagous; cereal crops are poor hosts Distribution in India: Throughout the country Symptoms: • Small patches of poorly growing plants • Stunted growth • Foliage starts turning yellow from older leaves, which wither away gradually • Root system is poorly developed • Extensive galling on roots • Galled roots show rotting symptoms afterwards Biology and Life cycle: Soil-borne, sedentary endoparasite. Second-stage juveniles infect the roots; the nematodes develop endoparasitically feeding on the vascular tissues. Adult females are sac-like, vermiform males leave the roots and come out in soil. Females lay eggs in masses on the surface of galls, or in advanced stages inside the compound galls. Life cycle is completed in 25-30 days during summer months. Dissemination: Through infected transplanting material, irrigation water, agricultural implements Losses: 40% Management options: • Deep ploughing 2-3 times during May-June • Seed treatment with carbosulfan (25ST) or Bacillus macerans at 3% w/w • Application of neem cake 1 t/ha at sowing in the main-field • Rotation with non-host crops like cereals 3|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati Root-knot Disease of Cucurbits Common Name: Root-knot nematode Scientific Name: Meloidogyne incognita, M. javanica Host Crops: Polyphagous (cereal crops are poor hosts); most affected crops like cucumber, pointed gourd, red pumpkin, bottle gourd, bitter gourd etc. Distribution: Throughout the country Symptoms: • Small patches of poorly growing plants • Stunted growth, reduced vine length and leaves • Foliage starts turning yellow from older leaves, which wither away gradually • Root system poorly developed • Extensive galling on roots • Galled roots show rotting symptoms afterwards • Reduced yield from nematode affected plants Biology and Life cycle: Soil-borne, sedentary endoparasite. Second-stage juveniles infect the roots; the nematode develops endoparasitically feeding on the vascular tissues. Adult females are sac-like, vermiform males leave the roots and come out in soil. Females lay eggs in masses on root surface on galls, or in advanced stages inside the compound galls. Life cycle is completed within 25-30 days during summer months. Dissemination: Through infected transplanting material, irrigation water, agricultural implements Losses: 20-50% Management options: • Deep ploughing 2-3 times during May-June • Seed treatment with carbosulfan (25EC) at 0.1% for overnight or vine/root dipping 0.05% for 6 hours • Application of neem cake/castor cake in pit at 30 g at least 10 days before planting or sowing • Enriched FYM with Purpureocillium lilacinum @ 1 kg in 25 kg FYM (incubation for 2 weeks) • Clean cultivation - destruction of infested plants/weeds immediately after harvest of crop • Rotation with non-host crops like cereals 4|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati Root-knot Disease of Carrot Common Name: Root-knot nematode Scientific Name: Meloidogyne incognita, M. javanica, M. hapla Host Crops: Polyphagous (cereal crops are poor hosts) Distribution: Throughout the country Symptoms: • Small patches of poorly growing plants • Yellowing of foliage • Small galls on feeder roots • Forking of carrots Biology and Life cycle: Soil-borne, sedentary endoparasite. Second-stage juveniles infect the roots; the nematode develops endoparasitically feeding on the vascular tissues. Adult females are sac-like, vermiform males leave the roots and come out in soil. Females lay eggs in masses on root surface on galls, or in advanced stages inside the compound galls. Life cycle is completed in 25-30 days during summer months; in winter it may be prolonged to 60-90 days under north Indian conditions. Dissemination: Through infected transplanting material, irrigation water, agricultural implements Losses: 34-42% Management options: • Deep ploughing 2-3 times during May-June • Apply neem cake/mustard cake @ 300-400 kg/ha at sowing • Apply neem cake @ 1 t/ha at planting for M. hapla • Rotation with non-host crops like cereals • Seed treatment with Purpureocillium lilacinum @ 20 g/kg seed, followed by soil application @ 2.5 kg/ha along with FYM @ 2.5 t/ha 5|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS Dr. S.S. Bhati Cyst Nematode Disease of Potato Common Name: Potato cyst nematode/Golden cyst nematode of potato Scientific Name: Globodera rostochiensis and G. pallida Host Crops: Main host potato, can also multiply on tomato, brinjal and certain weeds Distribution: Restricted to about 4000 ha area in Nilgiri, Palani and Kodaikanal hills bordering Tamil Nadu, Karnataka and Kerala. Recently recorded from Himachal Pradesh, Uttrakhand and Jammu & Kashmir also. Symptoms: • Foliage shows wilting during hot day time and recover by evening • Plants remain stunted in patches, foliage starts turning yellow from older leaves, which wither away gradually; leaving only a few green leaves on the top • Root system poorly developed, diseased plants can be easily uprooted • Tuber formation drastically reduced in number and size • Spherical white females/golden cysts of the size of a pin-head easily visible on roots Biology and Life cycle: Cysts contain 200-500 eggs that remain viable for several years. Hatching commences with the planting of host crop; potato root diffusates strongly stimulate the emergence of juveniles from cysts. Only 30-40% eggs hatch in a season; the remaining eggs hatch over a period of several years. The life cycle is completed in about 5-7 weeks under Nilgiri conditions, where a second generation may also occur. Dissemination: The cysts are spread to distant places through soil adhering to seed tubers Losses: Potato cyst nematodes inflict huge quantitative and qualitative losses in potato. While 26% losses are normal, the damage may be as high as 53-66% in badly infested fields. In severely infested fields, the yields may be even less than the tubers used for planting. Management options: • Grow non-host crops like cabbage, cauliflower, beetroot, radish, carrot, beans, strawberry and turnip 6|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants. NEMAT-531, NEMATODE DISEASES OF CROPS • Grow resistant potato cultivar, Kufri Swarna in rotation • Apply carbofuran (3G) @ 2 kg a.i./ha Dr. S.S. Bhati 7|Page Source: Walia and Khan. A Compendium of Nematode Diseases of Crop Plants.
