Gliocladium virens in an alginate prill ineffective as a biological control of Fusarium root disease in container-grown Douglas-fir

An alginate prill formulation of Gliocladium virens (GL-21) was added as a top-dressings (54 g per m²) or incorporated into medium (1.2 kg per m³) used to grow Douglas-fir seedlings in styrofoam containers. Seedlings in the top-dress treatment were similar to control seedlings; infection and colonization by naturally-occurring Fusarium was unaffected by treatment. Incorporated G. virens reduced seedling growth and increased occurrence and colonization intensity of Fusarium. In a laboratory experiment, inoculating Douglas-fir seedlings with G. virens (10% w/w) prior to inoculation with Fusarium increased survival time when compared to concurrent inoculations of fungi.University of Idaho, Idaho Forest, Wildlife and Range Experiment Station Contribution No. 742.