Temperature and Root Exudates On the Cereal Cyst-Nematode Heterodera Avenae

Abstract

English populations of Heterodera avenae hatched best in water at 10° or 15° after storage for at least 8 weeks at 2° or between 0° and 7°. Maximum total hatch over prolonged periods was at 15°, though for brief periods hatch rate was most rapid at 20°. Transfer to 20° briefly stimulated hatch after 8 weeks at 2° and 5° but after 10° the transfer had no significant effect. At 10° and 15°, root exudates of wheat, oats and barley (including varieties resistant to H. avenae pathotypes 1 and 2) stimulated hatch significantly. Root exudate activity is best detected in hatching tests of relatively short duration. No special relationship between cereal variety host status and exudate effects on pathotype has yet been found.