PRATYLENCHUS THORNEI - A CAUSE OF ROOT NECROSIS IN WHEAT

Invasion of wheat roots by Pratylenchus thornei Sher & Allen under field conditions, as well as in the absence of other microorganisms, caused lysis of cells, cavities, and eventually, destruction of the cortex. The number of P. thornei in roots increased exponentially with time. There was a significant linear regression between the logarithm of the number of nematodes in the inoculum and the logarithm of the number that invaded wheat roots (P<0.005). In a clay loam, the number of P. thornei decreased rapidly during storage in the absence of a host for 5 weeks and then more slowly for 50 weeks. This decline was more rapid at 30°C than at 10 or 20°C while at 40°C there were no survivors after 2 weeks. Air drying the soil from 19.5 to 5.0% w/w moisture killed 78.7% of the P. thornei present. © 1968 BRILL.