AvanzaBio has participated in a collaborative research project alongside the NUMAPS group from the Department of Plant Biology and Ecology at the University of the Basque Country (UPV/EHU), NEIKER, and Insekt Label to assess the potential synergy between the plant growth promoter (PGPS)-based biostimulant and mealworm excrement as an organic fertilizer in lettuce plants.

This study evaluated the effect of adding frass and a PGP-based biostimulant on the yield and quality of lettuce plants. It was found that low doses of frass increased both the yield and quality of the plant shoots, but medium-high doses reduced the fresh weight of the roots.

The PGP-based biostimulant also improved the yield and quality of lettuce plants. In addition, the combination of frass and PGP doubled the herbaceous biomass of lettuce, regardless of the dose of frass used. This suggests that there is a positive synergy between the two inputs, in which the biostimulant counteracts the toxic effects of frass at high doses.

As for the rhizosphere microbiota, the addition of frass did not affect bacterial abundance, but increased the incidence of some potential pathogenic fungi of the genus Fusarium. On the other hand, the biostimulant increased bacterial abundance and reduced the presence of fungi.

It is recommended to use the joint application of frass and biostimulant to obtain the best results in terms of yield and quality of lettuce plants.