松针红斑病的发病规律和防治

通过人工接种和野外定点观察实验,确定病原菌(Dothistroma pini)以菌丝和不成熟的分生孢子盘越冬。分生孢子葫发后从气孔或伤口侵入叶内。分生孢子主要靠雨水溅散作用传播,人为长途运输病苗和染病的接穗是当前长距离传播的主要方式。在整个生长季节都能放散孢子,以5—7月放散量较多。感病树种的纯林、混交林发病严重。修枝林分比未修枝林分病轻。距侵染源近的苗木和人工林发病严重。通过室内、外药剂试验,施放百菌清烟剂和喷洒百菌清或福美砷、福美双等液剂,都收到较好防治效果。

REGULARITY OF OUTBREAK AND CONTROL RED BAND NEEDLE DISEASE

From field investigations and inoculations, Dothistrama pini, the pathogen of red band needle disease was found to overwinter as mycelium and unmatured acervuli in infected needles. The germinating conidia were spread mainly by rain splash. The disease became widespread by transporting diseased seedlings and sciont. Conidia spread throughout the growing season,but mainly from May to July. The disease was found in both stand locations in each summer of investigation. The outbreak severity was serious in pure stands of susceptible pine and mixed stands with large components of susceptible pine, but slight in mixed stands of unsusceptible species with small components of susceptible hosts. The disease was less severe in pruned stands than in unpruned stands. The disease was most serious near the infection center. In indoor and outdoor tests, it was shown that Chlorothalonil smoke, Chlorothalonil spray (75%) and Thiram and Asomate sprays were effective control chemicals.