Rc.T.(DJtyl.J»7 



They should not be kept at too high a tenperatui-e bncause secondary rots 

 develope . 



Q. b-fould you explain how the nematodes are dried and kept in the refrig- 

 erator? 



A. We extract the nematodes from the infected tubers or plants and sieve 



them to get a clear suspension of the nematodes. We then filter out 

 the nematodes on filter paper. We hang the paper up to dry after which 

 the nematodes can be stored in the refrigerator for about two years and 

 sometimes more. Just put pieces of the filter paper in water to revive 

 the nematodes. 



Q. Do you think it is possible that the reason these nematodes fail to 



grow in the resistant plants is that the enzymes produced by the 

 nematodes fail to dissolve the middle lamellae? 



A. Yes, I thimc that is the reason in all those cases where there is 

 absolute resistance and no development of the nematodes. This is 

 true, not only for red clover, but also rye. There is a very slight degree 

 of dissolution of the middle lamellae in resistant rye. The nematodes may 

 develope to the fourth larval stage in rye, but cannot go on any further. 



