tailieunhanh - Fungicides for Plant and Animal Diseases Part 12

Tham khảo tài liệu 'fungicides for plant and animal diseases part 12', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | An Integrated Approach to Control the Black Leaf Streak Disease BLSD of Bananas while Reducing Fungicide Use and Environmental Impact 211 Box 6. Resistance monitoring The basic methodology relies on the comparison of the sensitivity to the different fungicides in fungal populations 50-100 spores sampled in commercial farms treated with the fungicides and fungal populations sampled in untreated locations. The monitoring of sensitivity is based on germination tests the germination of spores grown on agar media added with different concentrations of fungicides is compared with the germination of spores grown on agar de Lapeyre de Bellaire et al. 2010b . - For benzimidazoles susceptible strains do not germinate on agar added with the fungicide or have distorted germtubes. Resistant strains have a normal or short germtube as compared with the control on ager medium. - For sterol inhibitors the germ tube length is measured and the of growth inhibition GI is calculated for each strain at a specific concentration. The distribution of the GI in the population sampled in the treated farm is then compared to the distribution of the population sampled in the untreated farm. Another possibility is to evaluate the EC50 concentration concentration for 50 GI for each strain from GI assessed over a large range of concentration of the target fungicide. - For strobilurines the germ tube length is measured and the of growth inhibition GI is calculated for each strain at a specific concentration. A strain is considered as resistant if germ tube length or GI is over a threshold value. In the methodology approved by the FRAC see FRAC website monitoring methods MYCOFI fungal populations consist in ascospores obtained from necrotic leaf samples 20-25 plants are sampled in each location . At laboratory these necrotic leaf samples are bulked and incubated in a moist chamber for 48h and then leaf pieces are used for ascospore discharge on petri dishes enriched with the targeted fungicide. .