Urban development may cause adverse effects on the ecological integrity of natural areas in cities through habitat loss and fragmentation. Biological communities in habitat fragments may be altered which may, in turn, negatively impact ecosystem services that contribute to the sustainability of urban areas. As such, methods are required to assess anthropogenic impacts on urban habitats. Here, results are presented of ground beetle (Coleoptera: Carabidae) monitoring in habitat fragments in Coquitlam,BC. Ground beetle diversity in Coquitlam is highest in small, disturbed sites which include both native and introduced European species. Several European carabid species are effective biological indicators of anthropogenic disturbance in urban habitat fragments. Because of the relative ease of collection and identification of carabids, monitoring of carabids by citizen scientists can be used to assess human impacts on urban ecosystems.
Several mite species from the Phytoseiidae (Acari) have been successfully developed as products for augmentative biological control. Rearing of mites using factitious prey in grain-based systems can increase the efficiency of production of phytoseiids. This has been done successfully for several species but usually for Type III (generalist predator) phytoseiids. Neoseiulus fallacis (Garman) (Acari: Phytoseiidae) is a Type II phytoseiid (prefers spider mites) that is currently reared in British Columbia (Canada) on Tetranychus urticae Koch (Acari: Tetranychidae) in a plant-based system. Here, we present feeding behaviour and predation data for N. fallacis on T. urticae and three Astigmatid (Acari) mites: Lepidoglyphus destructor (Schrank) (Acari: Glycyphagidae), Aleuroglyphus ovatus (Tropeau) (Acari: Acaridae) and Thyreophagus entomophagus (Laboulbène) (Acari: Acaridae). Our objective is to identify a candidate factitious host for mass rearing of N. fallacis. Although N. fallacis grabbed prey mites of all four species, successful feeding attempts were more frequent for the native host, T. urticae, than for the three Astigmatid species. N. fallacis rejected A. ovatus and T. entomophagus as hosts more often than T. urticae. In predation trials, N. fallacis fed at the highest rate on T. urticae, at an intermediate rate on L. destructor, and at the lowest rates on A. ovatus and T. entomophagus. For the three mites tested, L. destructor is the most promising species for further development as a factitious host for N. fallacis.
The effectiveness of exclusion fences in preventing the colonization of carrot plantings by the carrot rust fly, Psila rosae (F.), was tested in small field plots. Fenced enclosures were surrounded by panels of mesh nylon window screen l20cm high. Control enclosures were left unfenced. Although the number of first generation P. rosae adults captured on yellow sticky traps was not significantly different between control and fenced enclosures, the number of second generation adults emerging within enclosures was significantly higher in control enclosures than in fenced enclosures. The percentage of unmarketable carrots, % damaged carrots, % urunarketable yield, % damaged yield, and number of lesions per carrot were all significantly higher in control enclosures than in fenced enclosures. We conclude that exclusion fences impede the colonization of carrot plantings by P. rosae and reduce damage to carrots. The results are discussed as they relate to pest management methods for thc carrot rust fly. Key words: Psila rosae; carrot rust fly; physical control; exclusion fences