Management Of Nuisance Fly Populations On Cattle Feedlots FLOT.306 Final Report prepared for MLA by: R Urech, PE Green, AG Skerman, MM Elson-Harris, JA Hogsette, RL Bright, GW Brown Department of Primary Industries and Fisheries, Queensland Meat and Livestock Australia Ltd Locked Bag 991 North Sydney NSW 2059 ISBN 9781741914610 May 2004 FEEDLOTS Management of nuisance fly populations on cattle feedlots FLOT.306 ABSTRACT................................................................................................. 3 EXECUTIVE SUMMARY............................................................................. 4 BACKGROUND .......................................................................................... 6 PROJECT OBJECTIVES ............................................................................ 6 METHODOLOGY ........................................................................................ 6 Survey – Fly control on cattle feedlots..............................................................6 Resistance to insecticides in flies from cattle feedlots...................................7 Fly and parasite population monitoring on cattle feedlots .............................7 RESULTS AND DISCUSSION.................................................................... 8 Survey – Fly control on cattle feedlots..............................................................8 Survey findings ..........................................................................................................8 Survey conclusions ...................................................................................................9 Resistance to insecticides in flies from cattle feedlots.................................10 Topical insecticide application ...............................................................................10 Cage assay ...............................................................................................................10 Fly and parasite population monitoring on cattle feedlots ...........................10 Adult fly populations ...............................................................................................11 Seasonal effects on fly catches ....................................................................................... 11 Comparison of feedlot sites ............................................................................................. 12 Feedlot management practices........................................................................................ 13 Observations of feedlot cattle behaviour........................................................................ 13 Immature fly populations ........................................................................................13 Seasonal effects ................................................................................................................ 13 Feedlot sites....................................................................................................................... 14 Effects of feedlot design and practices........................................................................... 15 Parasite populations................................................................................................16 Parasitic wasps.................................................................................................................. 16 Mites associated with feedlot flies................................................................................... 17 Entomopathogenic fungi .................................................................................................. 18 Fly and parasite population monitoring in other feedlots ....................................18 SUCCESS IN ACHIEVING OBJECTIVES ................................................ 19 IMPACT ON MEAT AND LIVESTOCK INDUSTRY.................................. 20 1 Management of nuisance fly populations on cattle feedlots FLOT.306 CONCLUSIONS AND RECOMMENDATIONS......................................... 22 Integrated pest management (IPM) for nuisance flies on cattle feedlots.....22 Elements of IPM for nuisance flies.........................................................................22 Reducing fly breeding sites ....................................................................................23 Using insecticides selectively.................................................................................23 Lot feeding design principles .................................................................................24 Enhancing populations of natural control agents.................................................25 Systematic monitoring of fly populations..............................................................25 Recommendations.............................................................................................27 BIBLIOGRAPHY ....................................................................................... 28 APPENDIX - FLY AND PARASITE POPULATION MONITORING ON CATTLE FEEDLOTS ................................................................................ 37 2 Management of nuisance fly populations on cattle feedlots FLOT.306 ABSTRACT Nuisance flies are recognised as a problem on Australian feedlots despite improved manure management over the past decade. The species, abundance and extent of breeding of nuisance flies and their natural enemies were determined on three feedlots. House flies were identified as the major fly problem and their chemical resistance status determined. Several biological agents, in particular parasitic wasps, played an important role in fly control. An integrated pest management (IPM) strategy for nuisance fly control is provided and further work is proposed, including the use of biological control agents such as wasps and entomopathogenic fungi. Implementation of the IPM strategy and further R&D should provide the industry with effective, sustainable and economic fly control. 3 Management of nuisance fly populations on cattle feedlots FLOT.306 EXECUTIVE SUMMARY The feedlot industry has applied a significant amount of effort to improved manure management practices over the past decade as a means of reducing odour emissions and fly problems. There is, however, evidence that fly populations remain a serious problem. Insecticide resistance and a desire to minimise the use of chemicals also drive the need to move to a more integrated approach to fly control. A questionnaire survey of Australian feedlots on fly control showed that 83% of feedlot operators considered flies a problem and that working conditions, human health, animal welfare, chemical residues and production losses were rated as the most important adverse impact of flies. The survey indicated that flies are controlled by a range of physical, cultural and chemical means. Almost 60% of the feedlots used some form of chemical fly control. Forty-three percent of respondents used baits, about a quarter used insecticide sprays, and 15% used traps to control flies. The effectiveness of these treatments was considered to be moderate by the majority of the respondents. The data collected in this survey was used to finetune the feedlot fly and parasite monitoring programs, select commonly used chemicals for resistance testing and formulate integrated pest management guidelines for the control of fly populations. Good control from insecticides relies on knowing what resistance is present in the fly populations and using the remaining effective chemicals in carefully planned programs. Flies from southern Queensland (SQ) showed a moderate level of resistance to diazinon (19 x), a lower level to trichlorfon (3.2 x) and were susceptible to azamethiphos and cyfluthrin. The central New South Wales (CNSW) and central Queensland (CQ) isolates showed moderate levels of resistance to diazinon (7 to 11 x), and appeared susceptible to azamethiphos and cyfluthrin. All feedlot isolates showed a reduced mortality response to Snip Fly Bait and the SQ and CNSW flies also showed a reduced mortality to Dy-Fly bait but not to the same extent as with Snip. The observed reduction in bait efficacy was due to a change in the flies’ behaviour. The impact on field efficacy of these baits is uncertain, although some loss of control might be expected. Populations of adult and immature nuisance flies and their parasites were monitored on three Australian feedlots with one SQ feedlot being continuously monitored over two years. The most commonly trapped adult flies on the SQ feedlot were house flies (Musca domestica, 38% of total fly catch) and hairy maggot blowflies (Chrysomya rufifacies, 27%). Other common species trapped were the bush fly (M. vetustissima, 15%) and the stable fly (Stomoxys calcitrans, 1.3%). All fly populations were low during the coldest winter months, house flies had one broad annual population peak extending over nine months, whereas stable flies showed two peaks in late autumn and late spring. House fly and stable fly populations were higher inside than outside the feedlot, whereas bush fly and blowfly catches were generally higher outside the feedlot. There was a strong correlation between the number of adult flies and behavioural responses of cattle irritated by flies. The frequency of tail swishes, ear flicks and head tosses can be used to gauge house fly and bush fly populations, and leg stomps correlated well with the stable fly populations. Systematic counts of the frequency of these movements can provide an estimate of