Development of a biological control for botrytis stem canker of greenhouse tomatoes caused by Botrytis cinerea Pers

Botrytis cinerea Pers. is a common fungal pathogen causing grey mould on a number of greenhouse ornamental and vegetable crops including greenhouse tomato (Lycopersicon esculentum Mill.). Botrytis cinerea infects tomato leaflets, petioles, stems, flowers and fruits.; The biological control potential of Trichoderma spp. is well recognized. The overall goal of this thesis research was to develop a biological control for B. cinerea on greenhouse tomato using a native strain of Trichoderma sp. from Alberta.; This study demonstrates some of the variability within T. harzianum and within B. cinerea using random amplified polymorphic DNA (RAPD) analysis. The variability present in T. harzianum indicated relationships between RAPD groupings and biological control potential. The better biological control strains grouped together and were generally distinct from the relatively poorer biological control strains.; RAPD analysis of B. cinerea clearly demonstrates the existence of geographic specialization in different strains of B. cinerea collected from across Alberta. Geographic specialization in B. cinerea has not been previously reported.; Two strains of T. harzianum (strains 7 and 29) from Alberta perform equally well as fungicides in reducing the length of lesions caused by B. cinerea as assessed using a greenhouse tomato petiole bioassay. As the tomato petiole bioassay was conducted in a greenhouse tomato crop managed to commercial production standards, these two biological strains of T. harzianum demonstrate excellent potential for commercialization.