Does vacuum-packaging or co-delivered amendments enhance shelf-life of Striga-mycoherbicidal products containing Fusarium oxysporum f. sp strigae during storage?

摘要

The effect of vacuum packaging on the shelf-life and handling of Pesta granules and seed treatment made with chlamydospores of Fusarium oxysporum strains Foxy2, PSM197 or their mixture was studied at 4C and 223C over 1 year. In addition, the effects of co-incorporated amendments [urea in Pesta or co-delivered fungicides (Ridomil Gold, Apron XL) on coated sorghum seeds], and coating material (Arabic gum 'AG', SUET Binder 'SB') on the viability of Striga-mycoherbicides were evaluated. Storage under vacuum packaging did not enhance shelf-life of the formulated Striga-mycoherbicidal products after 12 months of storage regardless of the treatment used. The co-incorporated urea into Pesta granules significantly reduced the viability of mycoherbicides, but less so at 4C (58% strain-stability after 12 months). No significant differences between the coating materials in maintaining the viability of mycoherbicides were observed. The shelf-life of isolates on coated seeds significantly decreased when adding Ridomil Gold. However, at 4C, the fungicide Apron XL allowed better survival of Foxy2 and PSM197 by maintaining their averaged half-lives (t 0.5) by an additional 6 months compared to Ridomil Gold. In general, Striga-mycoherbicidal product combinations exhibited a significantly higher shelf-life when stored at 4C than at 223C. The absence of a positive effect of vacuum packaging on shelf-life of Striga-mycoherbicidal products reflects the tolerance of the formulated fungal propagules (chlamydospores) to withstand an oxygen enriched environment and allows their handling and distribution through ordinary packaging systems in Africa. The high compatibility between Striga-mycoherbicides and the co-delivered fungicide Apron XL, and the fungal storage stability allows simultaneous control of Striga and fungal cereal diseases within an integrated pest management (IPM).