First Report of Curvularia Leaf Spot of Field Corn, Caused by Curvularia lunata, in Mississippi

Molecular identification of endophytic fungi in lawn grass (Axonopus compressus) and their pathogenic ability

Lawn grass (Axonopus compressus) is a widely distributed grass species from the family Poaceae that is ubiquitous in Malaysia. We isolated endophytic fungi from the leaves of A. compressus and molecularly identified them as Fusarium parceramosum, Colletotrichum siamense, C. gigasporum, C. endophyticum, Curvularia lunata, Stagonospora bicolor, Calonectria gracilis, and Albifimbria verrucari. These fungal endophytes are considered host generalists, as they have been isolated from other plants and have also been reported to be latent plant pathogens. We tested the pathogenicity of selected endophytic fungal isolates on A. compressus leaves, chili (Capsicum annum), and tomato (Solanum lycopersicum), and found that they were pathogenic to wounded A. compressus leaves with low to moderate virulence, and several were pathogenic to wounded and unwounded chili and tomato fruits. This indicated that the endophytes could infect both vegetable fruits with low to very high virulence. Pathogenicity tests demonstrated that endophytic fungi from the leaves of A. compressus can become pathogenic and infect the host and other plant species. The findings also indicated that leaves of A. compressus may harbor pathogens with latent ability that can become active due to changes in environmental conditions, thereby disrupting the balance between host-endophyte antagonism.

Curvularia lunata and Curvularia Leaf Spot of Maize in China

Curvularia leaf spot (CLS), primarily caused by Curvularia lunata (Wakker) Boedijn (C. lunata), is widely distributed in maize production regions in China. It occurs in all the developmental stages of maize and causes economic losses. The epidemic and yield loss estimation models have been constructed for the disease. C. lunata has obvious virulence differentiation and produces multiple virulence factors. CLS is managed by application of chemical and biological agents and by quantitative resistance conferred by 5 to 6 quantitative trait loci (QTL). This review summarizes research on the understanding of CLS biological characteristics, virulence factors of C. lunata, host resistance genetics, and disease management strategies in China.