Biological Control of Brown Leaf Spot Disease Caused by Curvularia Lunata and Field Application Method on Rice Variety IR66 in Cambodia

Curvularia lunata was found to cause a serious rice brown leaf spot in Cambodia. This is the first report of brown leaf spot on rice in Cambodia. All isolates were tested for pathogenicity. Dual culture antagonistic tests showed that Chaetomium cupreum inhibited sporulation of C. lunata when compared to the control. In a pot experiment, C. cupreum significantly reduced the incidence of brown leaf spot caused by C. lunata. After application of a spore suspension of C. cupreum, Chaetomium-biofungicide and chemical fungicide (tebuconazole) to rice seedlings inoculated with C. lunata, the disease was reduced by 68.79 %, 75.80 % and 72.41 %, respectively. In a field trial, the chemical method gave the best results in all plant parameters, followed by the good agricultural practice (GAP) and organic methods. The chemical method gave the highest panicle/plant, panicle length, panicle weight, grain weight/plant which were different from the GAP and organic methods. The chemical method also gave the best results in filled grain panicle-1, unfilled grain panicle-1, grain weight plot-1, dry hay weight plot-1, biomass weight plot-1 and harvest index, and was significantly better than the GAP and organic methods

Application of a New Bio-Formulation of Chaetomium Cupreum for Biocontrol of Colletotrichum Gloeosporioides Causing Coffee Anthracnose on Arabica Variety in Laos

The anthracnose pathogen was isolated from coffee leave and bean symptoms. Morphological and molecular phylogenetic data confirmed the species as Colletotrichum gloeosporioides. The pathogenicity of the isolate was also confirmed by detached leaf method which inoculated the virulent isolate into coffee leaves. The crude extracts with hexane, ethyl acetate and methanol solvents from Chaetomium cupreum CC3003 resulted significantly inhibited C. gloeosporioides that the ED50 values of 13, 11 and 28 ppm, respectively. The bioactive substances of C. cupreum CC3003 expressed antifungal activity against C. gloeosporioides as can be seen in the abnormal appearance of spores. A powder bio-formulation of C. cupreum significantly resulted to reduce anthracnose disease of 54.77 %. The application of nano-rotiorinol, nano-trichotoxin and a spore suspension of C. cupreum reduced anthracnose incidence of 46.23, 42.71 and 18.59 %, respectively while the inoculated control had high anthracnose disease. The application of bio-formulation of C. cupreum in powder form, nano-rotiorinol, and nano-trichotoxin to reduce coffee anthracnose was reported for the first time in Lao PDR

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