Tech. L:l 



PhEPAhATION OF NWIATODE SLIDE MOUNTS 



Accurate identification of plant and soil nematodes usually requires 

 the preparation of micrcscope slide mounts suitable for examination of 

 the specimens with the aid of the oil immersion objective lens. The 

 reader is referred to the section listinf^ laboratory equipment and 

 materials for details and discussions pertaining to manipulation of 

 nematodes and supplies needed for slide making. 



Usually the nematodes recovered from the soil or plant samples are 

 collected in Syracuse watch-glasses, in water and reasonably free from 

 soil and plant debris. Processed materials preserved in % formalin 

 and kept in vials may be emptied into watch-glasses in preparation for 

 slide making. The nematode samples are then examined with the aid of 

 the binocular dissecting microscope and the desired nematodes selected, 

 removed, and made into slide mounts. It should be noted that adult 

 specimens are required for identification to species and that it is 

 always worthwhile to mount several specimens of each kind of nematode 

 present. Usually considerable n\imbers of individual nematodes can be 

 mounted on a single slide, although it may be necessary to mount nema- 

 todes with relatively thick bodies separately from thinner nematodes. 



Nematodes may be examined while alive, but usually it is necessary to 

 inactivate them for detailed study. The very delicate complex struc- 

 ture of the nematodes requires appropriate means for killing, fixing, 

 and preserving; and the methods found satisfactory have been few. The 

 following table summarizes the types of slide preparations presented 

 in this manual. 



Type of Mematode Mount Temporary Semi-permanent Permanent 



Cyst forms (Heterodera) water 

 Root-knot (Meloidogyne) 



lactophenol 

 S% formalin 

 TAF 



lactophenol 



Eel-shaoed forms 



water 



"^t formalin 



TAF 



glycerine 



Head, tail and methyl- 



cross-section mounts cellulose 



glycerine- 

 jelly 



Helaxin,^ the nematodes prior to killing and fixing them is usually 

 done to reduce th° likelihood of distortion of the nematode in the 

 fixative. Heat is most generally used for this purpose. Ihe nema- 

 todes can be placed in a drop of water on a slide or put into a 

 depression slide and gently heated until activity ceases. Some workers 

 maintain an incubator at 52° C. for standardizing this heat treatment. 

 Larger samples of nematodes can be heated by adding a small amount of 

 hot water or by placing the sample, concentrated by centrifugation, in 

 a hot water bath at 65° C. for at least two minutes. 



