Horizontal distributions of zooplankton were investigated in two kettle lakes in southern Ontario . In Tory Lake a set of random samples at I m depth showed that Skistodiaptomus oregonensis and copepod nauplii were overdispersed (patchy) . In Lake St . George a 20 point grid sampled at each of 0 .5, 2, 4, and 6 m showed that Polyarthra spp ., Keratella cochlearis, Asplanchna spp ., Daphnia galeata mendotae, Bosmina longirostris, Eubosmina coregoni and copepod nauplii were all patchy in terms of both vertical and horizontal distributions . Contour diagrams showed that the patches tended to be comprised of unique groups of species . This was confirmed by principal components analysis which showed that Polyarthra spp . and K. cochlearis occurred together, that D . g. mendotae was found in a unispecies patch and that B . longirostris and E. coregoni were together . None of the zooplankton patches correlated with chlorophyll a measurements . A literature review suggests that there are four basic types of patches occurring in lakes and that there are at least 16 identifiable forces which might cause these distributions . The patch types are : I) large scale (> 1 km diameter), II) small scale, caused by wind-induced water movement, III) Langmuir circulation aggregations and IV) swarms, potentially caused by biotic factors .

23managers and technicians from Coillte Ireland for providing access to sites and helping with 24 trials. This research was funded by the BIOCOMES project co-funded by EU FP7. 30 EPN efficacy is predicted to be increased in organic soils. However, EPN efficacy in 31 suppressing LPW populations in peaty (organic rich) and in mineral soils was equal. 32 Weevil density and spatial distribution within stumps, which both vary depending on 33 soil type, explain how EPN parasitize and suppress the pests.

Entomopathogenic nematodes (EPNs) are effective against the immature stages of the large pine weevil Hylobius abietis. In three field trials we compared the efficacy of the application method of EPN for weevil suppression below the suggested threshold of 20 weevils per stump: applying the EPN suspension in the top edges of the stumps ('top') vs. drenching the soil around stumps ('standard'). For Steinernema carpocapsae, weevil suppression was below the targeted threshold only when suspension was applied in the standard way (two of the three sites). On the other hand, weevil suppression was provided in all three cases of 'top' application of Heterorhabditis downesi suspension, whereas suppression in 'standard' application was observed in one site. Percentage parasitism of developing weevils in relation to depth and distance help explain EPN movement post-application. Weevil suppression relative to suggested thresholds can be improved by altering the method of EPN application depending on the nematode species.