BP Singh

Treatment Schedules for Eradication of Nematodes from Germplasm 225without phytotoxic effects (Malek, 1974). M. ~apla were completelyeliminated from rose plants when the washed roots were dippedfor 39 min. in 0.1% solution of prophos (Mocap) and Nemacur at16°C (Dale, 1973).Uptake of nematicides by dormant plant parts may beinsufficient to eliminate nematodes occurring in the centre of thematerial (e.g., leaf nematodes in lily bulbs). Therefore, someworkers tried control of root kilot nematode'by immersion of plantmate:rial in nematicidal solutions at different temperatures. Thebioassay showed that immersion in phenamiphos for 60 min. at16°C or 30 min. at ~4°C eradicated M. javanica (Suatmadji, 1982).Zem et ill. (1980) reported that nematicides applied as a hot solution. were efficient in controlling nematodes but had adverse effects onplant growth.Other methodsMechanical seed cleaning is considered the major reason forthe disappearance of the wheat seed gall nematode, formerly acommon and serious pest in north - west Europe. In generalnematode infested seeds are generally shrunken, small andsometimes have'discolouration on the surface. The easiest way ofsalvaging is to extract all such seeds for further examination andtreat them, if needed. As symptoms are not clear in case of certainseed borne nematodes, such as A. agrostis in grass seed, A. besseyiin rice seed and D. dipsaci occurring in small particles of debrisassociated with onion, clover and lucerene seed, more refined seedcleaning methods might be expected to assist in the control of theirspread alongwith healthy seeds. Treatment for the whole lot ofsample is recommended.Ectoparasitic nematodes on root systems or other undergroundplant parts may also be effectively removed by light brushing orrubbing of the plant parts in a tank or a stream of water.Fumigation .with methyl bromide rarely penetrates plant tissuesufficiently to kill endoparasitic nematodes.Precautionary measuresWhenever scientists have a real choice between differentmeans of propagation for a particular crop, the one which preventstransfer of nematodes in planting material or enables thenematologists to examine material for nematode symptoms before