短小芽孢杆菌A3菌株对泡桐腐烂病菌的拮抗作用

室内平板拮抗作用测定,短小芽孢杆菌A3菌株对泡桐黑腐皮壳的菌丝及分生孢子均有较强的拮抗作用,抑菌圈直径为8～4cm。在林地3年防治试验结果表明,单用A8菌株的发酵液,防冶效果为97.8％;与多菌灵混用为99.4％。均比常用农药福美胂(89.3％)好。A3菌株拮抗物可使泡桐黑腐皮壳菌丝及分生孢子膨大畸形,进而胞壁破裂,内含物外流。

STUDIES ON THE ANTAGONISM OF BACILLUS PUMILLUS AGAINST PAULOWNIA CANKER

The antagonism of An A3 strain of Bacillus pumillus to the hyphae and conidia of the paulownia canker pathoses, Valsa paulowniae was tested with plate culture method. The results showed that the strain had strong antagonistic effects to the hyphae and conidia, with 3-4 cm in diameter of the inhabiting circle on the PDA plate inoculated with the A3 strain and the pathoses. Field experiments were carried out in the past three years on the control effect of fermented broth of the A3 strain and the fermented broth mixed with carbendazim against the canker. When the canker spots were scraped off and the tree trunk was treated with the broth or the mixture, 97.8% and 99.4% of control were achieved, respectively. Microscopic observations showed that treatment with the A3 strain of B. pumillus caused lysis of hyphae and conidia resulting from hypertrophying and malforming, cell wall breakdown and leaking of the cytoplasm.