Viability of Lolium endophyte fungus in seed stored at different moisture contents and temperatures

The effect of storage on viability of the Lolium endophyte fungus ( Acremonium loliae Latch, Christensen and Samuels) in seed of perennial ryegrass was studied. Treatments included four initial seed moistures (13.8, 12.1, 10.0, and 8.6%); different storage bags (calico, polyethylene film (9, 35, or 70 μm thickness), and laminated aluminium foil‐polyethylene); and four storage conditions (ambient 5–25°C, 5°C/70% RH; 0°C/30% RH; ‐15°C/90% RH). After 12 months of ambient temperature storage, seeds with final moisture contents > 11.3% had a rapid linear decline in endophyte viability from an initial 84% to < 15% at 13.0% seed moisture. Samples in 70 μm thick polyethylene and aluminium foil laminated packets had the highest endophyte viability (70–78%) at ambient temperatures. Seed stored at 5, 0, or ‐15°C had high endophyte viability with no effect of seed moisture. Seed germination was not affected by any treatments. Cool or low humidity environments (< 60% RH) are required to maintain viability of Lolium endophyte fungus in stored seed.