RELATIONSHIP BETWEEN HERBICIDE RESISTANCE IN LOLIUM-RIGIDUM AND POPULATIONS OF ANGUINA-FUNESTA, THE NEMATODE VECTOR IN ANNUAL RYEGRASS TOXICITY

Samples of annual ryegrass (Lolium rigidum Gaudin) seed tested for her bicide resistance were examined for seed-galls of Anguina funesta, the nematode vector of Clavibacter toxicus the causal bacterium in annual ryegrass toxicity (ARGT). Of the 246 samples examined, 63% contained galls, with concentrations up to 1400 galls per 10 g of seed. Higher h erbicide resistance was associated with increased concentrations of A. funesta. We conclude that use of selective herbicides for ARGT contro l may have contributed to the rapid development of herbicide resistanc e.