19 January 1996

Spud storage check advised

CHECK stored spuds now to ensure they have survived recent weather extremes, growers are urged.

The cold snap chilled some processing potatoes making them unsuitable for frying, says Chris Marshall, agronomist and store manager for March-based MBM Produce. The current mild spell will increase chitting risk, he adds.

"Cold causes starch in processing varieties to be converted into reducing sugars which affects fry colour. But growers wont know it unless they get tubers tested."

The problem is appearing as stores in the north are unloaded, says the Potato Marketing Boards Adrian Cunnington. "Most processing potatoes are stored at 8-10C in ambient stores. Despite insulation, temperatures dipped below this in some cases."

For a true picture of the damage, potatoes should be taken from likely cold spots, like the edges, front of the store and where there are known draughts, he advises.

Processors will test fry these . If a large number are affected, growers can try reconditioning, advises Mr Cunnington. As a guide, stores should be warmed to 12-15C two weeks before unloading, although adjustments need to be made for variety, crop maturity and site, he adds.

Mr Marshall agrees. "There is a very limited ware market for processing potatoes. So although it is an inexact science, it can be worth a try." Some varieties, such as Record and Piper, work better than others like Dell, he notes.

Small affected areas should be separated out if possible and sold into the bag trade, he suggests. "You dont want to downgrade a whole store if you can possibly help it, so dont try to mix them."

Ware growers also need to check stores as reports of chitting increase, says Mr Cunnington. The problem stems from the autumn when tubers treated with CIPC gas sprout suppressant were often too warm (above 10C) for optimum performance. The current mild spell is exacerbating this.

"A single dose is not always enough. In some cases growers have had to cut the period between doses to the minimum."

The problem is best prevented rather than cured, says Mr Marshall. "Growers should assess potatoes now to make sure the eyes are not opening. If they are, reapply gas. But check the label to ensure you dont exceed the maximum dose. Dont wait until the chits are half an inch long."

All the companys stores have been treated at least twice, he says. "Processing potatoes kept at 8-9C are treated almost as a programme. But some ware varieties, like Marfona, Piper, Santé and King Edward, can also grow, even at 4C."