Ear cockle of wheat

Ear Cockle is one of the serious problem of wheat. The symptoms associated with ear cockle of wheat is shown in this slide.

1. Presented by: Salu M aharjan Sarad G iri Saraswati Tandon Sauraz B.k. Saurav Luitel Ear cockle of wheat

2. First reported in England in 1743 by Needham. First reported in Nepal in 1966 and caused considerable loss in Rupendehi and Nawalparasi. The nematode is found in association with the yellow ear rot (tundu disease) caused by bacterium Clavibacter tritici. Corynetotoxin produced with the association are toxic to man and even death of cattle and sheep when such seed are feed.

3. Causal agent: Auguina tritici Pathogen is large nematode about 3.2 mm long and 120micrometer in diameter. Host: specific to wheat Nematode lays eggs and produces all its juvenile stages and adults in seed galls.

4. Anguina tritici

5. Symptoms Affects all growing stages. Infected seedlings are more or less severly stunted and show characteristics rolling and twisting of the leaves. A rolled leaves often traps the next emerging leaf and inflorescence within it and causes it to become bent or badly distorted. Base of the stem are enlarged, bent and generally stunted. Plants show spreading nature and tents towards more tillering.

6. Infected ears/kernels The affected ears are shorter and broader with very short or no awns on the glumes. The affected ears are greener than the healthy ones, and galls shed off the ear more readily than kernels. Diseased head may have one, few or all of its kernel turned into nematode galls. Galls are shiny at first but turn brown or black as the head matures. Mature galls are hard, dark, rounded and shorter than normal wheat kernels.

7. Disease cycle Seed gall nematode contains 1000 to 3000 larvae in a seed. Galls fallen to ground softens during warm, moist weather and release infective second stage juveniles. The juveniles swim upward on the leaves through film of water and feed ectoparasitically on leaves. When the inflorescence begins to form, the juveniles enter the flower primordia and produce the third and fourth stage juvenile and adults. Each infected flower primodium becomes a seed gall and may contain 80 or more adults.

8. Interaction with bacterium Anguina tritici plus Clavibacter tritici = yellow ear rot Nematode acts as a vector. Initial symptoms are same. Low temperature and high humidity favors this disease. Yellow slimy ooze from leaves, stem and ear heads. Upon maturity, turns brown. No grain formation. Ear heads may not emerge from boot leaf.

9. Management Use only healthy seed from healthy crop. Cleaning of contaminated seeds by sieving or floating in water. Crop rotation for 2.3 yrs such as barley or oat. Hot water treatment o f seed, first soaking seed in cold water for 4-5 hours and treating at 54°C. Soil application of nematicides such as Nemaphos, Aldicap@ 10 kg a.i/ha. Easy to eradicate both diseases easily.

10. Thank you For your patience.