Effects of Paratylenchus projectus on Growth of Sunflower. J. D. Smolik, Associate Professor, Plant Science Department, South Dakota State University, Brookings 57007. Plant Dis. 71:975-976. Accepted for publication 24 May 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0975.

Paratylenchus projectus significantly (P <0.05) reduced sunflower seed yields in a greenhouse study. Yield reductions occurred in both fertilized and unfertilized treatments and ranged from 12 to 33%. Application of fertilizer did not affect. P. projectus damage to sunflower. Populations of P. projectus increased 20- to 126-fold over 14 wk. Population increase of P. projectus on sunflower was highest at 20 and 25 C, and populations did not increase above initial inoculum levels at 10, 15, or 35 C.