Formulations for delivering Trichoderma atroviridae spores as seed coatings, effects of temperature and relative humidity on storage stability.

Aims: We aimed to evaluate different formulations for their ability to adhere Trichoderma atroviridae spores to wheat seeds, and promote survival during storage at a range of temperatures and relative humidities (RH).

Methods And Results: We tested a range of formulations for their ability to adhere T. atroviridae spores to wheat seeds. Treated seeds were stored for 6 months at a range of temperatures and RH, and spore viability among formulation was compared over time. Spore survival within formulations interacted significantly with environmental conditions. Notably, under optimum conditions (low temperatures and RH) best spore survival was recorded with a xanthan-gum-based formulation. Conversely under suboptimum conditions (high temperatures and RH), survival of spores was best in a waxy-starch formulation, but very poor in the xanthan-gum formulation.

Conclusions: These results indicate that T. atroviridae spores can be effectively delivered on to seeds and that a xanthan-gum formulation is promising when optimal storage conditions can be maintained.

Significance And Impact Of The Study: Most published formulation papers/patents only report survival of organisms over time at a single or limited number of temperatures and RH. For the first time, this study shows how different formulations are better suited to certain temperature and RH combinations.