核桃枝枯病菌生物学特性研究及药剂毒力测定

核桃枝枯病矩圆黑盘孢菌分生孢子萌发的最适温度为２７～３０℃，最高为３６℃，菌丝生长的最适温度为２５～２７℃，最高为３７℃，１５℃时生长迟缓。核挑树皮浸液对分生孢子萌发和产泡具有明显刺激作用，该菌在ＰＤＡ＋１０％核桃树皮浸液（简称ＰＤＡＢ）培养基上生长良好。菌落初期近白色，渐变为黄白色，后呈暗灰色，在２７℃恒温培养下１０天左右菌丝开始集结成团，１５天左右在菌丝团上形成露珠状物，并从中长出黑色分生孢子盘。用纸碟抑菌圈法对６种杀菌剂进行了毒力测定，以１２．５％速保利可湿性粉剂和５０％甲基托布津可湿性粉剂抑菌效果最好，４０％多菌灵胶悬剂和４０％福美砷可湿性粉剂次之，５０％速克灵可湿性粉剂、２０％粉锈宁乳油抑菌效果较差。

A Study on the Biological Characters of Melanconium oblongum Berk and the Toxicity Test of Fungicides

The results showed that extract (sap) of walnut bark stimulated the germination of conidia. In the medium PDAB (PDA+10% extract of walnut bark) the colony was white at the beginning, then turned to buff, and at last became dark grey. At the temperature of 27℃, hyphae formed into a mass in about 10 days. Dewdrops were formed on the mass and the black acervuli emerged from the dewdrops in about 15 days. The optimum temperature for hypha growth ranged from 25℃ to 27℃, the highest was 27℃, and the lowest was 15℃, while that for the germination of conidia ranged from 27℃ to 30℃. The highest is 36℃. The test of toxicity for 6 fungicides were carried out with the method of fungistatic-circle. The 12. 5% sumi-eight and 50% Topsin gave the best fungistasis. Bavistin and Asomate took the second place, and 20% Triadimefon and 50% Sumilex showed a poorer effectiveness.