Book Review

Abstract

Cultural control of sclerotia-forming plant pathogens is poor. However, with mounting environmental concern over the routine use of chemical soil sterilants such as methyl bromide and occurrence of enhanced degradation of soil-applied fungicides, interest in biological control of these fungi has increased. Most studies have focused on either the use of non-specific, antagonists such as Gliocladium and Trichoderma spp. or specific sclerotial mycoparasites such as Coniothyrium minitans and Sporidesmium sclerotivorum and various modes of action have been elucidated. Mycoparasitism can involve location, contact, recognition, penetration, intracellular growth and exit. Extracellular cell-wall degrading enzymes including ß, 1–3 glucanases, chitinases and proteases have received much attention but the role of antibiotics in mycoparasitism remains unclear. There is also a need to develop suitable selection methods for sclerotial mycoparasites. Novel screening systems for mycoparasites of Sclerotinia sclerotiorum related to the etiology of the disease, the edaphic conditions occurring in the natural environment and the projected method of application are described. In some glasshouse trials, C. minitans has given significant reduction of S. sclerotiorum disease in lettuce but control was dependent upon the level of disease, and time of year. C. minitans survived in the soil for over a year and spread throughout the glasshouse. Consequently, the need to understand the ecology of any mycoparasites selected for use as biological control agents must also be emphasized.