Source: Dick, Warren, Harry Hoitink, and Weizheng Zhang. 1997. Study shows compost enhances disease resistance. Am. Nurseryman 185:8 [1 April].

This article reported an increase in the disease resistance of plants grown in soils containing compost. There are certain microorganisms found in compost which could help to reduce the need for pesticides. The specific purpose of the study reported here was to determine if a systematic acquired resistance that utilizes these microorganisms is a factor in disease protection from compost. The idea of systematic acquired resistance is that if plants are infected by a mild strain of a microorganism, the plants increase their resistance to other, more serious disease-causing organisms. In terms of sustainability, microorganisms in compost make plants healthier, and the use of less pesticide has environmental and economic benefits. Researchers compared disease severity and peroxidase activity in cucumber plants grown with and without compost. Peroxidase activity can be described as a molecular marker for enhanced systemic acquired resistance. Germination was done in a pine-bark compost or a standard peat mix. Then seedlings were transplanted by placing half of the roots of each plant into two separate mixtures in which the seedlings were grown for 35 days. The results showed that no matter what the growing medium was, the cucumber plants that were germinated in compost had the overall better health. Other findings were that root rot was less severe for the roots growing in disease-inoculated peat, if the other half of the roots were growing in compost. Peroxidase activity was significantly enhanced for the plants grown in compost, and to an even greater degree when the plants were inoculated with the pathogen that causes anthracnose. It was found that it is critical for the compost and the pathogen to be present at the same time in order for systematic acquired resistance to activate rapidly. This research could lead to major advances in suppressing other bacterial diseases, which are very difficult to control.

Abstract Author: Leslie Power, 25 November 1997.

SUSAG Abstracts: Go back to the SUSAG Abstracts search page.