Cereal Cyst Nematode (Heterodera avenae) PDF

**Cereal Cyst Nematode (*Heterodera avenae*)** It was first discovered as parasite of cereals in Germany by Kuhn in 1874. In India it was first recorded by Vasudeva in 1958 from Rajasthan. Wheat and barley are the main hosts of this nematode in India. Oat is also an important host in Europe. In Raj...

**Cereal Cyst Nematode (*Heterodera avenae*)** It was first discovered as parasite of cereals in Germany by Kuhn in 1874. In India it was first recorded by Vasudeva in 1958 from Rajasthan. Wheat and barley are the main hosts of this nematode in India. Oat is also an important host in Europe. In Rajasthan and Haryana, it is known as 'Molya' disease of wheat and barley with a loss ranges from 8.2-28.8%. http://nemaplex.ucdavis.edu/images/Papp%20Heterodera%20Orig.jpg  Adult female of Cyst Nematode White females of *Heterodera avenae* from IARI fields **Biology :** The lemon shaped brown cysts, each containing about 400 eggs are formed at the time of crop maturity during March-April. The cysts detach from root and remain as such in soil till November. The J2 hatch and start emerging from cysts during November and continue till January. Only about 50% eggs hatch in one season, the rest remain viable till the next season. Host root exudates generally do not stimulate hatching. J2 penetrate the root just behind the root tip, after moving through cortex, become sedentary in vascular bundle and form syncytia. After feeding J2 grow in width, moult 3 times and become adult. In contrast to root-knot nematode, J3 and J4 stages of cyst nematode do not retain their shed cuticles and possess stylet, acquire flask shape without any spike. The posterior portion of the lemon shaped adult females rupture the root epidermis and emerges out from the root. They can be seen easily with naked eyes by the end of January as pearly white dots on roots. The females soon lay eggs inside their body, turn creamish and then brown cysts. The nematode completes only one generation in a year. The eggs in cysts can remain viable for few years. 3 Life cycle of ( a ) root-knot nematode and ( b ) cyst nematode (Abad and Williamson 2010 )   Life cycle of (a) root-knot nematode and (b) cyst nematode **Symptoms:** - Patches of stunted plants and chlorosis appear in the field when the crop is about 1-2 months old. - Tillering is greatly reduced, culms become thinner and weaker. - The affected plants may flower prematurely and ear heads bear fewer grains. - In severe infestation there may not be any grain formation. - Roots become typically bushy and swollen. - Appearance of white glistering females on the roots in Jan-Feb is confirmation of this nematode infection.  https://s3.amazonaws.com/soilquality-production/resources/7/original/Biol\_-\_CCN\_(fig2).PNG?1361763502  Oat roots infected with* CCN* appear swollen **Spread of disease:** This nematode spreads through soil, wind, irrigation water and farm implements. **INM:** - As this nematode is very host specific, crop rotation with non-host crops like mustard, chickpea, coriander, cumin, fenugreek, carrots for 1-2 years is very effective. - 2-3 deep summer ploughings during May-June reduce the nematode population drastically due to desiccation in hot weather. - Early sowing of wheat by a fortnight can reduce the crop loss. - [Growing of resistant varieties]. Barley varieties like **Rajkiran,** **C-164** and **BH 393** are resistant to this nematode where the nematode can do infection but fail to lay eggs, which reduces the crop losses as well as nematode population at the end of the cropping season. Resistant wheat variety **Raj MR-1** is released for cultivation in 'molya' infected fields. - In highly infected fields, application of carbofuran @ 2 kg a.i / ha gives 150-200% increase in wheat yield.