Study On The Current Situation And Prevention Countermeasure Of Euonymus Japonicus Thunb Diseases In Southwest Hubei Province

Euonymus japonicus Thumb, as a common tree used in afforestion of guard, iswidely used in afforestion of guard. According to the literature material, Euonymusjaponicus Thumb disease occurred universally in our country. But it did not happen insouthwest Hubei Province. The paper began from investigation in open country. Throughobserving at the time of disease, separation and cultivation of pathogen, research of thecharacteristic in biology, experiment of medical effect in the room, prevention andtreatment in the field, we found the present state that Euonymus japonicus Thumb diseaseoccurs, and put forward some countermeasures of prevention and treatment.The types of Euonymus japonicus Thumb diseases are mainly as follows: Oidiumeuongmi-japonicae (Arc) Sacc, Cercospora destructiva Rav, Colletotrichumgloeosporioides Penz, Sphaceloma euonymi-japonici Kurosawa and Sclerotium rolfsiiSacc after the investigation. Oidium euongmi-japonicae (Arc) Sacc was most serious, theless Cercospora destructiva Rav, the lest Sphaceloma euonymi-japonici Kurosawa andSclerotium rolfsii Sacc occurred seldom.Oidium euongmi-japonicae (Arc) Sacc often begins at the first ten days of April, itreaches the apex in the late of May, it stops to develop in the middle July in the late ofAugust. At the beginning of September to the first 10 days of November, the diseasereoccurs. And in the late of October, the disease reaches the apex once more. Cercosporadestructiva Rav begins at the early of May. It reaches the apex in the middle of June and itis more serious in the early of September to the early of November, which reaches theapex in the early of October. Colletotrichum gloeosporioides Penz begins at the late ofMay; it gets more serious in the late of June to the middle of September. The disease endsin November. Sphaceloma euonymi-japonici Kurosawa begins at the middle of May; itreaches the apex in the first ten days of June. In the late of July to the middle of August,the disease is less serious. But in the late of September to October, it is getting worse.Sclerotium rolfsii Sacc begins at the first ten days of June, it develops slowly in the late ofJuly to the late of August. But in the early of September, it is getting worse and it ends inthe early of October.To the research of characteristic in pathogen biology, it was fbunded that therequest of disease germ for the nutrition and the illumination were lax, but it was suitablefoe the acid environment.It showed that conidia of Oidium euongmijaponicae (Arc) Sacc could sprouted under the condition of the temperature around 5℃-30℃, the relativehumidity above 98%,with pH2～10. Conidia of Cercospora destructiva Ray couldsprouted under the condition of the temperature around 10℃-30℃, the relative humidityabove 70%. Colletotrichum gloeosporioides Penz might grow in the environment of thetemperature around10℃-35℃and acidity and alkali, its conidia could sprout in theenvironment of the temperature around10℃-35℃, relative humidity above 98%, pH3-8.Sphaceloma euonymi-japonici Kurosawa might grow in the environment of temperaturearound10℃-35℃, PH2～10, its conidia could sprout in the environment of thetemperature around10℃-35℃, relative humidity above 50%, pH3-9. Sclerotium rolfsiiSacc might grow in the environment of the temperature around10℃-35℃and acidity andalkali; its sclerotia could sprout in the environment of the temperature around15℃-40℃,relative humidity above 90%, pH2-10.Discovered from the present state of the disease, the environment of the hightemperature and dampness was the primary factor causing the disease; meanwhilemanagement of the plantings was also the main cause which the disease occurred. Theexcessive density of transplant, the barren soil, ponding easily, the extensive managementand weak growth etc. will benefit to the diseases therefore. In order to preventEuonymus japonicus Thumb disease, we should strengthen the management, control thedensity of planting, ventilate and penetrate the trees, combine pruning of trees, removethe disease leaves and disease tree top, and improve the ability to resist the disease.Secondly at the beginning and prime period of disease, we could use 50% CarbendazimWP, 70% Thiophanate-methyl WP, 50%Mancozeb WP, 75%Chlorothalonil WP diluting800 times to prevent and cure the disease.