Nematode Paste in Horticultural Crops and their Management

Under Ground Symptoms (Contd..)

5. Root knots or Root galls
The abnormal galling or swelling of the roots is a specific diagnostic symptom of nematode infestation.
Meloidogyne spp. produce characteristic galls on the roots and host plants.
The size and number of galls vary from species to species and host to host.

• While woody plants like cotton and carnation show small galls, very large galls are produced on cucurbits which may coalesce with each other in a way that the entire root looks swollen and deformed.
• Extensive galling is often observed on crops like tomato, okra, brinjal etc.

Extensive galling of okra roots and Heavily galled cucurbit roots


Heavy galling in tomato seedlings under nursery conditions and Polyhouse grown cucumber roots infested by Root knot nematode

Small galls produced on carnation roots and Cabbage roots infested by root knot nematode

• Ditylenchus radicicola produces small galls on grass roots.
• Globodera rostochiensis produces swellings on tomatoes roots where they may reach a size resembling galls.
• Nacobbus serendipiticus produces large galls on tomato.
• N. batatiformis produces large galls on beet.
• Galls and distorted roots may also appear in strawberries and soybean attacked by Xiphinema diversicaudatum
• Hemicycliophora similis induce galling in cranberry and Hemicycliophora sp. produces similar galling on lemon roots.

6. Cysts on Roots
Cyst nematodes do not cause major malformations or lesions on roots. However, their ‘pearly’ white swollen cysts (dead females) are often observed adhering to the root which can be seen easily by careful examination of roots with a magnifying glass.

Cysts of Heterodera avenae on wheat roots