Wonistances5 



GROWTH OF HARROW VELVET IN THE 

 PRESENCE OF TWO PRATYLENCHUS Spp 

 RELATIVE TO SOIL TEMPERATURE 



rEMPERATURE °F 



Figure 3, This variety of tobacco (Harrow Velvet) in contrast to the 

 varieties illustrated in figures 1 and 2 is susceptible to both species 

 of Pratylenchus. 



THE EFFECT OF SOIL TEMPERATURE 

 UPON TWO SPECIES OF PRATYLENCHUS 

 IN THE ROOTS OF BURLEY I 



SOIL TEMPERATURE °F 



Figure 4. The optinium soil temperature for Pratylenchus minyus and P, 

 penetrans is shown to be quite different. This observation was use J to 

 maintain different levels of nematode inoctilum in establishing the "dosage- 

 response" curves. 



