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Item Selected studies on strains of Botrytis cinerea : a dissertation presented in fulfilment of the requirements for the Master of Science at Massey University(Massey University, 1986) Stewart, Terrence MarkSome characteristics of benzimidazole and dicarboximide resistant and susceptible strains of Botrytis cinerea and the chemicals that control them were studied. Difference in sporulation or sclerotial production could be not be used to differentiate between fungicide resistant or susceptible strains. Generally, mycelial growth of dicarboximide low-level resistant strains was slower than that of susceptible strains on unamended malt extract agar and was considerably so on media amended with 0.68 M NaCl. No benzimidazole low-level resistance was detected in the benzimidazole susceptible strains tested. Fourteen strains of B. cinerea were screened for the ability to sporulate in the dark to assess the feasibility of using material which filtered Ultra-violet light as a glasshouse covering. Eleven of these strains sporulated in complete darkness. Chlozolinate showed a high degree of protectant and systemic activity against dicarboximide susceptible strains but was poor on low-level resistant strains. PP192 showed high protectant but no systemic activity on both susceptible and low-level resistant strains. Sub-lethal doses of vinclozolin and iprodione on plant surfaces were shown to stimulate the sporulation of B. cinerea from an inoculum source such as an agar plug.Item Biological control of Botrytis cinerea on kiwifruit : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticulture Science at Massey University(Massey University, 1992) Sada, Samir ShamouelScreening for potential antagonists was carried out on plant parts of kiwifruit (Actinidia deliciosa var. delicisa [A.Chev]. Lang & Ferguson, cv. Hayward) taken from kiwifruit orchards in four collections. A range of microorganisms have shown potential activity against Botrytis cinerea Persoon. ex Fries, on Potato dextrose agar (PDA) petri dish at various temperatures, including 0°C. The antagonism was also tested on different media with different pH for antibiosis or mycoparasitism action. It was found that temperature had a much greater effect on growth and activity of the antagonists than did pH. Three isolates (FB3, FF9, FO30) which showed good biocontrol activity were tested for ability to inhibit spore germination and germ tube elongation of B.cinerea on 2.5% vegetable juices (V.8) medium discs. One of these isolates (FO30: Fusarium merismoides) showed such ability. These isolates were selected for a trial on kiwifruit. Stem end rot was partially controlled under storage condition when the pathogen (B.cinerea) and the antagonist were inoculated simultaneously. Harvested fruit were inoculated with different inoculum levels and subjected to different curing periods. The inoculum level of Fusarium merismoides isolate FO30 showed a significant affect on the percentage of soft rot caused by B.cinerea, and reduced disease incidence on kiwifruit by 17-21% after 13 weeks storage at 0°C. The curing period did not have any significant effect on the percentage of soft rot except when the fruit was cured for 2 days at ambient temperatures, inoculated, and left 2 further days at ambient temperatures before storage at 0°C. Further work is required to investigate enhancement of biocontrol of B.cinerea on kiwifruit by manipulation of the curing period. Several microscopic stains including Chlorazol black, Lactophenol cotton blue and phloxine gave good staining of the spores and mycelium of B.cinerea and antagonists on 5% V.8 medium and kiwifruit tissue.
