First biological control tests of Neopestalotiopsis clavispora in Costa Rica

Abstract: Crown rot of strawberry caused by Neopestalotiopsis clavispora is a serious disease. This pathogen infects several crops, including apple, crabapple, sweet cherry, grape, peach, pear and ornamental plants. The use of synthetic pesticides contributes to loss of biodiversity and risks to both aquatic and terrestrial environments, poses risks for human health. Biological control using antagonistic fungi is a promising strategy for managing N. clavispora. Three strains of Trichoderma asperellum, T. viride, and T. longibrachiatum were provided by Garsol Biological Laboratory. In the dual tests, substrate competition was classified as class II according to the scale used for the three Trichoderma species. The contact time was 96 hours for T. asperellum and T. viride, but it was faster (72 hours) for T. longibrachiatum. Growth inhibition percentages (PCI) for antibiotics ranged from 70.55 % to 81.38 %, with T. longibrachiatum showing the highest values (81.38 %) and significant differences in all confrontations. This is the first biological control test of N. clavispora causing crown rot of strawberry in Costa Rica. This pathogen could pose a serious and emerging threat to several crops, including blackberry, strawberry, and ornamental plants.