SummaryAn Australian parasitoid wasp, Psyllaephagus pilosus, was collected from a previous release site in France and introduced into a commercial eucalyptus foliage plantation in Co. Kerry in the south west of Ireland to control the eucalyptus (blue gum) psyllid Ctenarytaina eucalypti. The first parasitised psyllid nymphs were observed 26 days after the release was made in late May 1998, and 49 days elapsed before a new generation of adult parasitoids was seen. Visually assessed indices of psyllid parasitism and adult wasp incidence were used to quantify the pattern of adult dispersion and establishment. A second generation of adult wasps emerged in late August, initiating a rapid spread of parasitism throughout the release site during September that culminated in a peak rate of almost 100% parasitism by late October. Subsequently by the end of 1998, an apparently random process of dispersion and successful natural colonisation occurred at eight out of ten monitored plantations at distances up to 70 km from the release point. The first colonisers of the other two sites arrived very late in 1998, and consequently failed to establish viable populations by the following summer. Probably this failure was because the small numbers of colonisers had arrived too late in the growing season to effect population establishment before the onset of winter. Assisted introductions were, therefore, made at these sites in June and August 1999, respectively. Once fully established, the parasitoid had no difficulty in surviving winter conditions at all monitored sites and demonstrated excellent potential as a biological control agent.

In trials conducted in a mushroom crop grown in commercial growing bags and inoculated with the dipteran pest, Lycoriella solani, and/or the predatory mite Parasitus bituberosus, the mite reduced adult pest numbers ty 50-66%. It also reduced the numbers of larval Heteropeza pygmaea, a second dipteran pest which occurred as a contaminant in one trial. Fewer mites were extracted towards the end of the cropping period. No evidence was found of an oscillating relationship between predator and prey over the trial period. Crop yield was increased by 18% and unsaleable yield was reduced by 50%. It is suggested that the mite can contribute to an integrated pest management system.

The eVect of storage temperature (9 and 20ë C) on North West European Heterorhabditis megidis isolate UK211 for control of Otiorhynchu s sulcatus larvae at 9ë C is assessed. O. sulcatus mortality increased from 2 5.3% (corrected mortality) using freshly produced nematodes, to 27.1% using nematodes that had been cold-stored for 12 weeks. The number of nematodes invading the insect larvae increased almost 27-fold. Nematode storage at 9ë C for 11 to 12 weeks weeks resulted in signiWcantly higher O. sulcatus mortality (41%) than storage at 20ë C for 2 to 3 weeks (12%). Thus, cold storage does enhance nematode infectivity for O. sulcatus larvae.

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