Antifungal Activity of Native Trichoderma afroharzianum and Arcopilus cupreus Against Neopestalotiopsis rosae Causing Strawberry Root and Crown Rot in Mexico

Root and crown rot of strawberry is an emerging disease of concern in Mexico. Like other soil-borne diseases, it has spread widely due to the vegetative propagation of this crop. This study aimed to evaluate the in vitro antagonistic activity of four native Trichoderma strains and one strain of Arcopilus cupreus against a population of Neopestalotiopsis rosae, as a potential biological control alternative. Thirty-five commercial strawberry fields across the three main strawberry-producing states were sampled, yielding 103 fungal isolates. Nearly 70% of the recovered isolates belonged to the Neopestalotiopsis genus. Sixteen representative isolates were identified as N. rosae based on morphology and multilocus sequence phylogeny (ITS, β-tub, tef1-α) and confirmed as pathogenic through pathogenicity tests. Four native T. afroharzianum isolates recovered from the rhizosphere of healthy strawberry plants were identified by multilocus sequence analysis (rpb2, tef1-α). All T. afroharzianum isolates exhibited antagonistic activity in dual-culture assays, inhibiting mycelial growth by 71–73%, surpassing the effectiveness of the commercial fungicide cyprodinil + fludioxonil (average inhibition 50%). In contrast, the A. cupreus isolate recovered from a native medicinal plant showed an average inhibition of 38%. These results highlight native T. afroharzianum as a promising sustainable alternative for integrated management of strawberry root and crown rot in Mexico.