KẾT QUẢ ĐIỀU TRA TÌNH HÌNH BỆNH VÀNG LÁ, CHẾT CÂY TRONG TÁI CANH CÂY CÀ PHÊ TẠI ĐẮK LẮK

Currently the leaves of coffee trees replanted on the old soil grounds often become yellow leaves and death, which leads to none successive rejuvenation, while requirements of production realities, coffee areas that need for rejuvenation become more and more increased. The results of the investigation showed that the coffee gardens had seriously been affected by yellow leave disease and death before replanted in Cu Kuin district - Dak Lak, in which slight rates (below 20%) were accounted for 56% and heavy rates (over 20%) were accounted for 44%. Successfully replanted coffee gardens (≤ 20% of coffee trees showing yellow leaves and death) were 65.15%; unsuccessfully replanted coffee gardens (> 20% of coffee trees showing yellow leaves and death) were 34.85% in total. The measures of thorough soil plough, root collection, soil exposure, planting hole treatment, organic fertilizer application and use of healthy seedlings have positively influenced on the rate of successful rejuvenation. The main factors affecting the success of replanted coffee gardens include use of the basal organic fertilizer > amount of basal organic fertilizer > plowing and collecting roots to burn > methods in digging holes to grow > amount of organic fertilizer after replanted > organic fertilizer application after replanted > control measures > origin of coffee seedlings> age of coffee gardens before eradication. However, depending on the specific conditions, the influence of these factors may be different. From the results of the investigation, it is shown that coffee gardens could be immediately replanted after 6 months to 1 year if they were of high ages (usually > 20 years old), low productivity and coffee trees uninfected with yellow leaf disease and death. They must be rotated before rejuvenation in the case of the coffee gardens being of not high ages (typically ≤ 20 years) before eradication, and coffee trees infected with yellow leaves and death (usually> 10%). To replant successfully, it is necessary to apply measures for treatments before rejuvenation (soil plough, root collection, soil exposure and so on), use of healthy seedlings, organic fertilizer application before and after rejuvenation, and hole treatment by chemical/biological products.