THE STRAWBERRY DISEASE IN LANARKSHIRE

Abstract

Summary. In the field two aspects of the “Lanarkshire Straw‐berry Disease” are apparent, namely, the devastation en masse of the strawberry beds. and the diseased condition of individual plants. Soil conditions as a whole are unfavourable, and this tells against the development of an extensive and healthy root system. The roots are weak and lax. consequent on the excessive stiffness of the soil. This renders them liable to fungal attack. Roots of all kinds were found to be penetrated by fungal hyphae. and to have hyphae associated with them. Eighteen separate extractions of fungi were made, and on twelve occasions a species of Pythium was the only fungus obtained. When inoculated into pots in which strawberry plants had been grown under sterile conditions, the Pythium attacked young and old roots: and produced all the symptoms of the disease. The Pythium was isolated again in the laboratory from inoculated plants. This evidence demonstrates that the Pythium is capable of producing the strawberry disease as it occurs in field conditions. It is concluded that Pythium is an important factor in exploiting the root system on which the general health of the plant depends. The problem appears to be an agricultural rather than a mycological one. The main factor involved appears to be the general health of the plant. The fungal attack is to be regarded as an important accessory to the main Factor. It is, however, a factor which has become increasingly aggressive owing to the accentuation of certain soil conditions. Experimental work on the soil is being carried out side by side with the mycological studies.