Botrytis spp. cause gray mold and are significant pathogens of pulse crops (dry pea, lentil, and chickpea). Seedling infection can result in plant stunting and death. In this study, 100 Botrytis isolates were recovered from pulse crop seed samples that were submitted to the Regional Pulse Crop Diagnostic Laboratory at Montana State University. Nine Botrytis spp. were found to be associated with pulse seeds in Montana based on a combination of cultural characteristics; the amplification of partial sequences of the G3PDH, HSP60, and RPB2 genes; and phylogenetic analysis. Botrytis cinerea (n = 54) was the predominant species, followed by B. euroamericana (n = 22) and B. prunorum (n = 11). There were a few isolates of B. mali and five novel Botrytis spp. that included one cryptic species. To determine the pathogenicity and aggressiveness of the isolates, dry pea cultivar Lifter, lentil cultivar Richlea, and chickpea cultivar Sierra, detached leaves were inoculated using mycelial plugs. Lesion diameter produced by Botrytis isolates on three hosts differed (P < 0.05). Aggressiveness of B. cinerea was high in all three hosts and varied among the tested isolates. Spore inoculations were conducted on greenhouse-grown dry pea, lentil and chickpea plants using one sporulating isolate each of B. cinerea, B. prunorum, and Botrytis sp. 1. Results indicated that these isolates were pathogenic on the tested hosts. This study illustrates that many species of Botrytis are associated with pulse crop seed in Montana and can be aggressive on multiple crops, which may have implications for disease management.
Keywords: Botrytis cinerea; Botrytis euroamericana; Botrytis mali; Botrytis prunorum; chickpea; dry pea; lentil; pulses; seedborne.