Application method and growing medium affects the response of cucumber seedlings to inoculation with Trichoderma harzianum

Abstract

Cucumber seeds were inoculated at sowing with a mixture of seven isolates of Tvichoderma harzianum, previously observed to confer plant growth promotion in commercial horticulture. The Trichodevma mixture was applied by three different methods: spore-coated organic pellets, a dried biomass powder, or seed coating. These were added to three different growing media: sterile potting mix, field soil (naturally containing a Pythium sp.) or field soil drenched with captan. The number of healthy cucumber seedlings was recorded after 8 days. There was no effect of inoculation in potting mix. The number of healthy seedlings was lower in the untreated field soil than in the soil treated with captan. The numbers of healthy seedlings were lower in the pellet and dried biomass treatments than in untreated field soil, but with seed coating, the numbers of healthy seedlings were not significantly affected. The effect of seed coating was tested again, with the isolates of T havzianum applied individually and as a inixture to field soil. There was no significant effect on the number of healthy seedlings compared with controls in any Trichoderma treatment.