The inhibition of Colletotrichum acutatum by monochromic pulsed and non-pulsed radiation at different time durations

Colletotrichum species infect up to 80% of horticultural plants, and cause anthracnose disease, especially in strawberries (Fragaria ananassa), and reduces yield by over 50%. The selection of specific radiation conditions for targeted plant protection resolves the pathogen resistance problem to chemical plant protection products. This study aimed to evaluate the effects of non-pulsed and pulsed monochromic blue (B; peak = 470 nm), cyan (C; peak = 505 nm), yellow (Y; peak = 590 nm), and red (R; peak = 627 nm) radiation-emitting diodes (LED) at 32 Hz frequency at 4 and 8 h light durations cycles in vitro and evaluated them as potential plant protection means for strawberry C. acutatum. The photon flux density (PFD) of each LED wavelength was 20±2 µmol m^‑2 s^‑1. Our data showed the highest inhibition of C. acutatum mycelium growth achieved under non-pulsed C radiation at 4 h duration, and at Y radiation at 8 h duration. The lowest recovery was achieved under pulsed B radiation at 8 h duration. The results revealed that C. acutatum mycelium colour varied, despite the duration of light. The colour of mycelium under R and Y was white, however, under C and B NDASH seashell. In summary, the effect of LED wavelength and light duration affects C. acutatum. However, more studies on applying pulsed LED lighting should be done to prepare the recommendations for innovative plant protection technology.