Role of Trichoderma aggressivum f. europaeumas Plant-Growth Promoter in Horticulture

The main objective of this study was to determine the capacity ofTrichoderma aggressivumf.europaeumto promote pepper and tomato seedling growth compared to that ofT. saturnisporum, a species recently characterised as a biostimulant. Consequently, in vitro seed germination and seedling growth tests were performed under commercial plant nursery conditions. Additionally, the effects of different doses and a mixture of both species on seedling growth under plant nursery and subsequently under greenhouse conditions were determined. Furthermore, mass production of spores was determined in different substrates, and their siderophore and indole acetic acid production and phosphate (P) solubilisation capacity were also determined. Direct application ofTrichoderma aggressivumf.europaeumto seeds in vitro neither increases the percentage of pepper and tomato seed germination nor improves their vigour index. However, substrate irrigation using different doses under commercial plant nursery conditions increases the quality of tomato and pepper seedlings. Tomato roots increased by 66.66% at doses of 10(6)spores per plant. ApplyingT. aggressivumf.europaeumorT. saturnisporumunder plant nursery conditions added value to seedlings because their growth-promoting effect is maintained under greenhouse conditions up to three months after transplantation. The combined application of the two species had no beneficial effect in relation to that of the control. The present study demonstrates the biostimulant capacity ofT. aggressivumf.europaeumin pepper and tomato plants under commercial plant nursery and greenhouse conditions.