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Chilli anthracnose is a major infectious disease of the genus Capsicum. Chemical control is the primary means of controlling this disease; however, the excessive use of chemical pesticides can adversely affect ecological security and human health. Here, our aim was to explore the synergistic effects of chemical and biological pesticides in the control of chilli anthracnose. The bacterial strain LY7, which is antagonistic to the anthracnose-causing fungus Colletotrichum scovillei, inhibited the growth of C. scovillei by 83.52%. Through morphological and genetic analyses, this strain was identified as Bacillus velezensis. Then, the compatibility of LY7 with three common chemical fungicides was determined. The in vitro protective and therapeutic efficacies of the 1 × 109 CFU/mL (colony-forming unit/mL) bacterial solution were 66.38% and 35.18%, respectively, but both were significantly lower than those of prochloraz, the most compatible fungicide. We then conducted field efficacy trials to elucidate the best combination of prochloraz and LY7; the highest control efficiency was achieved with a suspension of 1.0 × 108 CFU/mL of LY7 mixed with 0.75 g/L prochloraz (3:7 ratio). Electron microscopy revealed the inhibitory effects of LY7 and prochloraz on C. scovillei mycelial growth. These results suggest that an LY7-based biofungicide can partially replace prochloraz, serving as an integrated management strategy to control chilli anthracnose. [ABSTRACT FROM AUTHOR]

Choanephora rot of Chenopodium plants (CRC) was observed at the flowering stages in seven plantations of Shanxi Province, China. CRC had caused leaf, stem, and panicle neck rot of C. quinoa, panicle neck and stem rot of C. formosanum, and stem rot of C. album. Typical symptoms included water-soaked, rapid soft rotting, and abundant sporulation on the whole panicle necks, stems, and leaves. Based on morphological characteristics, phylogenetic analyses, and pathogenicity tests, the pathogens were identified as Choanephoraceae cucurbitarum. Sporangiola and sporangiospore of C. cucurbitarum germinated at 30 °C and were able to germinate by two h post-inoculation (hpi). The germination rates of sporangiola and sporangiospore significantly increased at 3 to 4 hpi, and the germination rates ranged from 91.53 to 97.67%. The temperature had a significant effect on the pathogenicity of C. cucurbitarum the optimum pathogenic temperatures for stems of C. quinoa, C. formosanum and C. album were 30 °C after one day post-inoculation. Choanephoraceae cucurbitarum could infect white and red quinoa panicle necks between 20 and 30 °C, and the average lesion lengths were 0.21 to 3.62 cm. Among the five tested fungicides (boscalid, dimethomorph, isopyrazam, propiconazole, and tebuconazole), isopyrazam showed higher sensitivity to sporangiola germination of C. cucurbitarum, with an EC50 value of 0.6550 μg/mL. Isopyrazam and tebuconazole strongly inhibited the sporangiospore germination of C. cucurbitarum, which showed EC50 values of 0.4406 and 0.3857 μg/mL. To our knowledge, the present study found for the first time that C. cucurbitarum is a pathogen causing panicle neck of C. formosanum and stem rot of C. formosanum and C. album, while CRC first appeared in the quinoa panicle necks, and gradually expanded to stems and leaves. [ABSTRACT FROM AUTHOR]