Reduction of viability of soil borne inoculum of common bunt (Tilletia tritici) by collembolans

Summary

Teliospores of Tilletia tritici (syn. T.caries) were fed to five species of collembolans: Onychiurus cebennarius, Mesaphorura macrochaeta, Folsomia fimetaria, Proisotoma minuta and Orchesella villosa. Faeces were collected from all species. Only faeces from M. macrochaeta did not contain teliospores. Ingestion by the four other collembolan species reduced germination rates of T. tritici teliospores from 76.5% in the control to below 3% after ingestion. There were no significant differences between the germination rates after ingestion by the different collembolan species. Two soil types, a sphagnum based potting medium and a coarse sandy field soil, were inoculated with 0.1, 0.2 or 0.3 mg of teliospores, and incubated with 15 F. fimetaria or P. minuta for 3 days. In both soil types the collembolans significantly reduced the proportion of viable spores in the two lowest inoculation levels. The effect of collembolan density on the infection of wheat was tested by inoculating field soil in 5 l. pots with 2.0 mg of teliospores and adding between 0 and 10000 P. minuta per pot. Incubation with densities of 3000 P. minuta or higher per pot for 10 days before sowing, reduced the infection of wheat from 30% in the control to 3.5%.