Preliminary evaluations of parasitic nematodes for grass grub (costelytra zealandica (white)) control in central hawke’s bay of new zealand

Abstract

Mortality of third instar grass grub occurred in the laboratory at lower temperatures with Neoaplectana glaseri Steiner than with Heterorhabditis bacteriophora Poinar. Field applications of N. glaseri were sprayed onto small plots at 3 or more rates in late December 1981, mid March 1982, and late April 1982. The highest level of control (66%) was recorded from late December applications of 25 × 104and 50 × 104nematodes/m2. Reduction in grass grub levels from late April applications was not significant. The mortality — nematode response curve appeared to vary from asymptotic to curvilinear, with mortality declining at the highest rate (100 × 104/m2). The possible reason for the latter relationship is discussed. © 1982 Taylor & Francis Group, LLC.