Abstract

Discovered in 1961 on the Nilgiris for the first time in India. Heterodera rostochiensis has been a very serious pest, known popularly as "Golden Nematode of potatoes". Repeated surveys were made to locate and keep track of the spread of this infection in the potato fields and the current estimate of the affected area is 3050 acres which is approximately 15% of the total area cultivated under potato in the Nilgiris. On the Nilgiris the Golden Nematode appears to have been introduced along with seed imports in the past (Seshadri and Sivakumar 1962). Its multi- plication and spread is found encouraged by the prevalence of mono-cropping of potatoes year after year and the conducive climate. Infestation at the level of 50 Cysts per 100 mille-litre of soil has been known to affect crop performance and reduce yields. Infection at higher than 300 cysts per 100 mille-litre is observed to very severely affect the yield. Often at this level of infestation, farmers fail to harvest a crop. Symptoms of nematode infestation include an unthrifty stand, (in the initial stage), yellowing in patches, similar to N defici- encies, and dying out of whole plants. Symptoms may manifest on an entire field, or in parts of it, depending upon the distribution of the nematode popula- tion in the area.

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