11 August 1995

Demo shows cheaper ways to fight off eelworm in potatoes

SOARING eelworm populations on potato land can be controlled at less cost, growers heard at a field demonstration held by the Farm Supply Company at Kirklington, Bedale, North Yorkshire.

The problem has escalated on intensive potato growing land in the Vale of York to the point where 25% of the best land on some farms is no longer able to sustain a potato crop. Heavy capital investment means growers are reluctant to stop growing potatoes, notes Eric Hutchinson, technical manager at FSC in Thirsk.

Rather than face 20 years freedom from potatoes for nematodes to decline naturally, FSC was demonstrating trap cropping technology to bring about an 80% reduction in egg counts.

One snag with growing a crop for six weeks and then lifting before female nematodes lay their eggs is cost. FSC calculates that cultivations, seed, planting and harvesting costs up to £665/ha (£269/acre). And that takes no account of the value of the crop lost for that year.

Unfortunately, says Mr Hutch-inson, MAFF will not accept trap cropping as part of a farms set-aside requirement. But, the cost can be cut by using latest grid sampling technology to identify "hot spots" within fields, allowing trap cropping or soil sterilisation to be confined to smaller areas.

A crop of Cara, grown for six weeks at one end of a field where egg counts were particularly high, was being lifted using a modified Reekie stone and clod separator to clear the crop for composting.

The alternative to trap cropping, soil sterilisation with Telone, was also demonstrated.

Unfortunately lack of soil moisture on the light land site was not conducive to the prototype achieving a satisfactory seal. &#42

New nematode "hot spot" identifying methods can help target soil sterilisation and trap cropping. But dry soils can prevent effective sealing when sterilising with machines like this prototype from Ramsay.