Sporulation of the Fungus Hirsutella rhossiliensis from the Nematode Criconemella xenoplax. B. A. Jaffee, Visiting Assistant Professor, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29631. E. I. Zehr, Professor, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29631. Plant Dis. 67:1265-1267. Accepted for publication 26 May 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-1265.

Hirsutella rhossiliensis emerged from colonized C. xenoplax when incubated for 1 day at 25 C in moist chambers or soil. Emergent hyphae branched infrequently and developed phialides and spores after 2–3 days. With the host nematode as the only substrate, about 700 spores per nematode were produced in moist chambers. Sporulation ceased after 21 days. Optimum, maximum, and minimum temperatures for sporulation from colonized nematodes on agarose were about 25, 30, and 10 C, respectively. Spore production was generally high between pH 5.5 and 7.0, the range common in South Carolina peach orchard soils. Sporulation on agarose was not stimulated by KCl or NaCl. Decreasing the osmotic potential below –5 bars with these salts suppressed spore production until few or no spores were observed at –40 bars.