EXCESSIVE MANURING.

Auckland Star, Volume LXII, Issue 202, 27 August 1931, Page 10

EXCESSIVE MANURING.

BIRKDALE STRAWBERRIES.

ONE CAUSE OF IHSEASE

MYCOLOGIST'S DIAGNOSIS

In pursuance of His investigation of the root disease in strawberry plants, an examination of several plots in the Birkdale district was made yesterday by Dr. C. H. Cunningham, mycologist at the plant research station at Palmerston North. He was accompanied by Mr. L. Paynter, senior orchard inspector, and Messrs. C. P. Gibson, Talbot, and Kennedy, orchard inspectors. The party was shown over the district by Messrs. T. M. Shepherd, president, W. A. Christensen, secretary, E. Rainford, G. McGregor, and P. H. Taylor, executive members of the Birkdale Fruitgrowers' Association. The number of plant in the beds injspected ranged from 20,000 to 60,000. Of the seven visited two were badly affected, one grower having lost 10,000 plants; in the five other beds the disease was patchy. Subsequently Dr. Cunningham addressed a meeting of growers in the Birkdale Hall, there being a large attendance, and interest was keen. Mr. T. M. Shepherd presided. Dr.' Cunningham said that from the cursory examination he had made, he believed the chief problem was not • so much disease, as faulty strawberry growing. Root rotting and dying out of plants was confined to areas overlying a heavy subsoil. Volcanic soil was more porous, and did not appear to be so troublesome with the same plants and the same treatment. He was inclined to think the major factor of the trouble was the heavy doses of manures on this soil. An orchard tree took more out of the soil than the strawberry. The average dose was four to six cWt. For grass the maximum was 1$ to 2 cwt of manure j a year. Here they were applying 3 to 3£ tons a season. This was beyond all rea-, ■son, because no plant could possibly use 1 one-tenth of the quantity. The manures were poisoning the plants. The disease was usually most severe in the low-lying patches, the dying off in these patches being due to the chemicals depositing there. In porous soil, or volcanic soil, the effect would not be the same, as the manures -would leak through the soil. The c'|iy land prevented this leaking, and the result was a deposit on the low-lying-soil. The first thing to do towards a remedy was to make a big reduction in the doses of manure. Three or four tons per acre a season was abnormal; it was really to grow strawberries in bags of superphosphate. He advised an experiment without manures on lauds which had been so heavily manured. . That one factor stood out prominently. The other problem was virus disease, possibly the same as the one that caused great damage on the Pacific Coast. That could only be determined by experiment. After answering questions, and acknowledging a resolution of appreciation of his visit, Dr. Cunningham said he could offer the services of the research station should; the growers decide to carry on experimental work. To introduce virus-free plants and bulk them up to supply the district was the solution, but this was going to be a .matter of several years.