RESUMEN
We present two whole-genome sequences of Colletotrichum strains which were isolated from Eleusine indica and Echinochloa crus-galli using Nanopore and Illumina technologies, as part of screening for potential mycoherbicide. The genome sequences will provide important genetic information and will be useful for further research into secondary metabolites of Colletotrichum.
RESUMEN
Barnyardgrass (Echinochloa crus-galli (L.) Beauv.) is one of the most troublesome weeds in transplanted and direct-seeded rice worldwide. To develop a strategy for the biocontrol of barnyardgrass, fungal isolates were recovered from barnyardgrass plants that exhibited signs of necrosis and wilt. An isolate B-48 with a high level of pathogenicity to barnyardgrass was identified after pathogenicity tests. From cultural and DNA sequence data, this strain was identified as Colletotrichum echinochloae. The inoculation of the barnyardgrass plant with C. echinochloae caused a significant reduction in fresh weight. The isolate B-48 was highly pathogenic to barnyardgrass at the three- to four-leaf stages. When inoculated at a concentration of 1 × 107 spores/mL, barnyardgrass could achieve a reduction in fresh weight of more than 50%. This strain was safe for rice and most plant species. The results of this study indicated that this strain could be a potential mycoherbicide for barnyardgrass control in paddy fields in the future.
RESUMEN
Alternanthera philoxeroides (Mart.) Griseb. is an invasive herbaceous amphibious weed species in China. A pyralid moth Herpetogramma basalis (Walker) was discovered feeding on A. philoxeroides through field surveys and may be a potentially useful biocontrol agent. To determine the host range of H. basalis and evaluate its potential to control A. philoxeroides, no-choice and multiple-choice tests were conducted. Herpetogramma basalis fed on target weeds and 29 nontarget plant species. In addition to the target weed A. philoxeroides, H. basalis developed to adult on eight other nontarget species. Herpetogramma basalis survived to adulthood successfully on A. philoxeroides and less successfully on several other Amaranthaceae species. In multiple-choice studies, H. basalis showed a strong oviposition preference for A. philoxeroides over Amaranthus tricolor L. (Centrospermae: Amaranthaceae). Amaranthus tricolor was the only crop plant that supported the complete development of H. basalis. We cautiously recommend H. basalis for the biological control of A. philoxeroides in China.