Plans To Eliminate Blight From Pea Crops

Press, Volume CVI, Issue 31167, 17 September 1966, Page 9

Plans To Eliminate Blight From Pea Crops

Plans for the elimination of bacterial blight from field pea crops in Canterbury are discussed by Dr. H. C. Smith, director of the Crop Research Division, and Dr. R. C. Close, of the Lincoln sub-station of the Plant Diseases Division, in a Canterbury Chamber of Commerce agricultural bulletin.

They note that during annual disease surveys of pea crops in Canterbury between 11953 and 1964 bacterial blight ■ was not recorded, but last year it was recorded in Canterbury on about 90 per cent of the crops of autumn-sown field peas inspected and on 5 [per cent of the spring-sown field peas. It was not found in any commercial crop of spring-sown garden peas inspected during NovemberDecember last year. It was apparent that spring sown crops were much less likely to encounter conditions

favouring bacterial blight. As spring sowing of garden peas had been standard practice for more than 20 years this has probably been the main factor which has enabled garden peas in Canterbury to remain free from infection with this disease.

The scientists say that preliminary inquiries in the United States have shown that they do not have any highly resistant varieties and the absence of a breeding programme for resistance indicates that they have found the most efficient method of

control is to use healthy seed. Obviously this is the first method of control that should be adopted, they say. “The Department of Scientific and Industrial Research considers that it is practicable and essential that bacterial blight be again eliminated from all seed pea crops in Canterbury. It is essential, because then health certificates can be endorsed that the area is free of this disease and the high quality of New Zealand pea seed can be maintained. At present we cannot certify that Canterbury is free from bacterial blight, for although garden peas were free, most field peas were severely infected last season The United Kingdom and South Africa require the health certificates for pea seed to be endorsed to the effect that the crop was grown in an area where bacterial blight was not known to occur, or that the crop has been inspected and found free from the disease.

“Recommendations regarding the necessity for sowing seed only from healthy crops of field peas and an inspection service by the D.S.I.R. and Department of Agriculture have been laid down for the coming season.

“The purpose of an inspection service will be to identify disease-free lines of Partridge peas. This seed can then be further multiplied to provide additional supplies of diseasefree seed. It is to be hoped that eventually all the Partridge pea seed in use will have been derived from disease-free crops. It is recommended that the present identified lines of clean seed be used as much as possible in 1966 and that they be sown on different soil types in both autumn and spring in order that any slight infection may be detected. In 1965 many crops of field peas were not inspected and could be carrying infection in the seed.

“Seed merchants have been asked to submit to the local office of the Department of Agriculture, before the end of September, a list of contract field pea crops for inspection. Those inspected in 1965 and found free of the disease must be placed at the top of the list. Farmers with crops, not under contract, should submit their names and acreages to a seed merchant for forwarding to the department. After the applications have been received, the percentage of crops to be inspected for disease will be decided locally by the department. A ballot will be used to select the con-tract-free crops for inspection. It would be appreciated if every assistance be given to the department in locating crops for inspection. Both autumn and spring-sown crops will be eligible for inspection.

“At harvest, clean crops should be harvested before an infected crop. If infected crops have been harvested, then it is recommended that the first three bags or an equivalent quantity of bulk seed be rejected when harvesting a clean inspected crop. In addition, it is important that headers and seed-dress-ing equipment (including portable dressers) be cleaned thoroughly before heading or dressing clean seed crops. Merchants have agreed to being responsible for the identification in store of the seed from crops found to be free of the disease. "Complete co-operation in this campaign for clean seed of field peas has been obtained from the seed merchants, Federated Farmers, D.S.I.R. and Department of Agriculture. Canterbury can look forward to the production of dis-ease-free seed of all peas in the near future and the elimination of the disease from the province. With this should come a better appreciation of the quality of our field and garden peas.”