Research On Nematicidal Activity Of Some Strains Of Paecilomyces And Their Allies

The nematodicidal activity of 36 strains Paecilomyces and their allies agaist nematode Panagrellus redivivus was tested. The pathogenic course of A-43-1 to nematode was observed and its bioactive component was extracted and separated. The results were briefly summarized as follows.Based on pathogenic tests of 36 strains to nematodes, 5 high-virulent strains have been obtained. They are P. cateniannulatus-11, A-43-1 , H-A-37-1 , A46-1 and H-104-2. Strains with more than 90 percent of mortality to Panagrellus redivivus were A-43-1 and H-A-37-1 on CMA medium; P. cateniannulatus-11 has about 90 percent of mortality to Panagrellus redivivus on Sabouraud's medium. What's more, A-43-1 not only kills nematodes, but also dyes them red whole body.The morphological characters of high-virulent strains were described detailedly.Based on the result of experiment, the strain P. cateniannulatus-11 has showed a better activity of extracellular enzyme. So we speculate on that the fungus secretes firstly extracellular enzyme and decomposes nematodes subsequently. The bioactive component from H-A-37-1 and A-43-1 has thermal stability, so it is possible that the hyphae secrete directly nematicidal toxin, which knocks them down at first and then decomposes nematodes.On the CMA medium, strain A-43-1 produces red water-soluble pigment, when the nematodes tested are added onto the media with red pigment, they gradually are dyed red and dead after about six hours. Afer 24 hours, the cuticle of nematodes are decomposed wholly. The mortality of nematodes tested is to reach about 95 percent. As the check media, the Sabouraud's medium and PDA medium have red water-soluble pigment and no death of nematodes tested. The mortality of nematodes tested in area of CMA without red pigment is only 10-20%. It is presumed that some elements of CMA media are make for producing the nematicidal materials. Production of this bioactive compound perhaps are correlative with the red water-solbule pigment.The mycelial growth and nematicidal activity of A-43-1 in different solid media were determined. The key component of these solid media is wheat, wheat bran, white rice, corn, malt powder and soybean powder, respectively.By liquid fermentation, the hyphal growth and nematicidal activity of A-43-1 fermentative liquid were tested. The result showed that the bioactive component of A-43-1 was in the fermentative liquid, and it can be produced stably under the condition of having...