EFFECT OF SCLEROTIAL DAMAGE OF SCLEROTINIA-SCLEROTIORUM ON THE MYCOPARASITIC ACTIVITY OF TRICHODERMA-HAMATUM

Damaged sclerotia of Sclerotinia sclerotiorum buried in soil infested with Trichoderma hamatum isolate TMCS-3 were degraded rapidly when the medulla of sclerotia was completely exposed by the feeding activity o f larvae of the fungus gnat Bradysia coprophila. These heavily damaged sclerotia also enhanced in vitro, the growth of TMCS-3. Growth of TMC S-3 in liquid culture was studied using different carbon sources as su bstrates, including sclerotia of S. sclerotiorum. Significantly more b iomass of TMCS-3 was recovered using sclerotia as a substrate compared to other carbon sources tested. Exudates fr om sclerotia whose melani zed rinds had been completely removed by feeding larvae accelerated th e germination of conidia of TMCS-3. Concentrations of amino acids, car bohydrates and proteins in the sclerotial exudates were not increased as damage to sclerotia was increased. Exudation of electrolytes was hi gher in undamaged than damaged sclerotia. Glucanase activity of TMCS-3 was slightly increased when the fungus was exposed to damaged sclerot ia. However, chitinase activity was not increased by damaging the scle rotia. Larval damage altered the sclerotia not only physically but als o chemically, thereby enhancing the activity of the fungus T. hamatum.