Q.51 Which of the following plant diseases is/are caused by nematode?
(A) Cereal cyst of barley
(B) Ergot of rye
(C) Wart of potato
(D) Ear–cockle of wheat

Correct Answer: (A) and (D)

Cereal cyst of barley and ear-cockle of wheat are caused by nematodes. The other options involve fungal pathogens.

Option Analysis

Cereal Cyst of Barley (A)
Cereal cyst nematode (Heterodera avenae or H. filipjevi) attacks barley roots, forming cysts that stunt growth and reduce yields by up to 50%. White females visible on roots turn into brown cysts post-harvest.​

Ergot of Rye (B)
Ergot results from the fungus Claviceps purpurea, replacing rye grains with toxic sclerotia that cause ergotism in humans and animals. No nematode involvement occurs.​

Wart of Potato (C)
Potato wart stems from the fungus Synchytrium endobioticum, producing tumor-like galls on tubers via zoospores. Nematodes do not cause this disease.​

Ear-Cockle of Wheat (D)
Anguina tritici nematode induces seed galls in wheat ears, distorting plants and filling grains with nematode masses. This seed-borne pathogen spreads via contaminated seeds.​

Introduction to Nematode Plant Diseases

Plant diseases caused by nematodes rank among key topics for CSIR NET Life Sciences, affecting crops like barley and wheat. These microscopic worms damage roots or seeds, leading to stunted growth and yield loss. Understanding causal agents helps differentiate nematode issues from fungal ones.​

Nematode-Caused Diseases in Cereals

• Cereal Cyst of Barley: Heterodera avenae invades roots, creating cysts that limit nutrient uptake in barley and wheat. Patches of yellowed, stunted plants appear, worsening under drought.​

• Ear-Cockle of Wheat: Anguina tritici transforms wheat seeds into galls, shortening ears and twisting leaves. Seed transmission sustains the disease across seasons.​

Non-Nematode Diseases

Ergot of rye involves Claviceps purpurea fungus producing toxic ergots, not nematodes. Wart of potato arises from Synchytrium endobioticum, forming warty tubers via fungal zoospores.​

Management Strategies

Crop rotation with non-hosts like legumes reduces nematode populations. Resistant varieties, clean seeds, and nematicides control spread for cereal cyst and ear-cockle. Early detection via root inspection prevents yield losses up to 50%.​