PreOac.funt;i;( 



the presence of eelworms that, so to speak, stirs up the blood 1t.:.\:, of 

 the fimfTus. That, I think, is a very important point when we corne to 

 consider eelworm control, which we are going to do later. 



Now, if I may turn just for a. moment to the internally parasibic fvu;'i, 

 fungi in such genera as Harposporium and AcrostalaPTnus . I am not goinr' 

 to spend much tijne on them, because they are much less important for 

 our purpose. These attack eelworms, usually through the agency of a 

 sticky spore. They produce very small spores which stick to the cuticle 

 of eelworms, and when the spore germinates, it sends a germ tube through 

 the cuticle and forms a mycelium inside the victim. The mycelium then 

 grows at the expense of the internal organs of the eelworm until the 

 body of the worm is completely filled with hyphae. It does not do the 

 eelworm any good at all, of course. After the host has been consumed, 

 the fungus pushes fertile hyphae out to the exterior. On these fer- 

 tile hyphae the spores are formed. 



These fungi are very common, but whether or not they would ever be of 

 any practical use for eelworm control, I rather doubt, because of the 

 difficulty in handling them. They have mostly been reported as being 

 obligate parasites, but whether that is so, or whether it is merely 

 that attempts have not been made to culture them, I could not tell you. 

 Their isolation, certainly in most cases, would be difficult. 



Discussion 



Q. Do these nematode trappin,^ fungi show any specificity as to kinds 

 of nematodes for prey? 



A. The nematode traooing fungi show very little soecificity, if any. 



The internal parasites appear to be miich more specific; most of 

 them go for more than one species of eelworm, but actually their range 

 of hosts has not been worked out. I wo\ild say the internal parasitic 

 fungi show quite a lot of specificity, and the traopers show very 

 little. 



Q. Wliat is the stimulus for closin-]; of the rings in some of the ring 



forrr.s? Is it any m.echanical stimulus, or is it something more 

 specific? 



A. Purely mechnaical. The rings can be made to close by stroking 

 them with a needle, and they can also be made to close by heat. 

 Hovjever, I do not think heat is operative in nature, unless, perhaps, 

 the eelworm is running a fever. 



Q. 1/flnat technique do you use for isolation of the fungi from the soil'." 



A. v/ell, I use the same technique for v/hatcver matr^rial I take the 



fun-^i fromj that is, I firnt get a mix.^d cu].t\n-e and then isolate 

 the desired forms from it. An a general techniq^je, I put the material 



