Cattle herd inspections and fly trapping for the detection of the Old World screw-worm fly (Chrysomya bezziana)

ObjectivesTo compare the sensitivity of inspections of cattle herds and adult fly trapping for detection of the Old World screw-worm fly (OWS). ProceduresThe incidence of myiases on animals and the number of OWS trapped with LuciTrap (R)/Bezzilure were measured concurrently on cattle farms on Sumba Island (Indonesia) and in peninsular Malaysia (two separate periods for the latter). The numbers of animal inspections and traps required to achieve OWS detection at the prevalent fly densities were calculated. ResultsOn Sumba Island, with low-density OWS populations, the sensitivity of herd inspections and of trapping for OWS detection was 0.30 and 0.85, respectively. For 95% confidence of detecting OWS, either 45 inspections of 74 animals or trapping with 5 sets of 4 LuciTraps for 14 days are required. In Malaysia, at higher OWS density, herd inspections of 600 animals (twice weekly, period 1) or 1600 animals (weekly, period 2) always detected myiases (sensitivity = 1), while trapping had sensitivities of 0.89 and 0.64 during periods 1 and 2, respectively. For OWS detection with 95% confidence, fewer than 600 and 1600 animals or 2 and 6 LuciTraps are required in periods 1 and 2, respectively. ConclusionsInspections of cattle herds and trapping with LuciTrap and Bezzilure can detect OWS populations. As a preliminary guide for OWS detection in Australia, the numbers of animals and traps derived from the Sumba Island trial should be used because the prevailing conditions better match those of northern Australia.

Specific detection of the Old World screwworm fly, Chrysomya bezziana, in bulk fly trap catches using real-time PCR.

The Old World screwworm fly (OWS), Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), is a myiasis-causing blowfly of major concern for both animals and humans. Surveillance traps are used in several countries for early detection of incursions and to monitor control strategies. Examination of surveillance trap catches is time-consuming and is complicated by the presence of morphologically similar flies that are difficult to differentiate from Ch. bezziana, especially when the condition of specimens is poor. A molecular-based method to confirm or refute the presence of Ch. bezziana in trap catches would greatly simplify monitoring programmes. A species-specific real-time polymerase chain reaction (PCR) assay was designed to target the ribosomal DNA internal transcribed spacer 1 (rDNA ITS1) of Ch. bezziana. The assay uses both species-specific primers and an OWS-specific Taqman MGB probe. Specificity was confirmed against morphologically similar and related Chrysomya and Cochliomyia species. An optimal extraction protocol was developed to process trap catches of up to 1000 flies and the assay is sensitive enough to detect one Ch. bezziana in a sample of 1000 non-target species. Blind testing of 29 trap catches from Australia and Malaysia detected Ch. bezziana with 100% accuracy. The probability of detecting OWS in a trap catch of 50 000 flies when the OWS population prevalence is low (one in 1000 flies) is 63.6% for one extraction. For three extractions (3000 flies), the probability of detection increases to 95.5%. The real-time PCR assay, used in conjunction with morphology, will greatly increase screening capabilities in surveillance areas where OWS prevalence is low.

An improved real-time PCR assay for the detection of Old World screwworm flies

The Old World screwworm (OWS) fly, Chrysomya bezziana, is a serious pest of livestock, wildlife and humans in tropical Africa, parts of the Middle East, the Indian subcontinent, south-east Asia and Papua New Guinea. Although to date Australia remains free of OWS flies, an incursion would have serious economic and animal welfare implications. For these reasons Australia has an OWS fly preparedness plan including OWS fly surveillance with fly traps. The recent development of an improved OWS fly trap and synthetic attractant and a specific and sensitive real-time PCR molecular assay for the detection of OWS flies in trap catches has improved Australia's OWS fly surveillance capabilities. Because all Australian trap samples gave negative results in the PCR assay, it was deemed necessary to include a positive control mechanism to ensure that fly DNA was being successfully extracted and amplified and to guard against false negative results. A new non-competitive internal amplification control (IAC) has been developed that can be used in conjunction with the OWS fly PCR assay in a multiplexed single-tube reaction. The multiplexed assay provides an indicator of the performance of DNA extraction and amplification without greatly increasing labour or reagent costs. The fly IAC targets a region of the ribosomal 16S mitochondrial DNA which is conserved across at least six genera of commonly trapped flies. Compared to the OWS fly assay alone, the multiplexed OWS fly and fly IAC assay displayed no loss in sensitivity or specificity for OWS fly detection. The multiplexed OWS fly and fly IAC assay provides greater confidence for trap catch samples returning negative OWS fly results. © 2014 International Atomic Energy Agency.

Warm-season greens grass trial - Environmental and management guidelines suited for new and old cultivars

The Horticulture Australia funded project, Management Guidelines for Warm-Season Grasses in Australia (TU05001), has allowed a detailed greens grass study to take place and enabled researchers and superintendents to work together to collect meaningful data on a range of Cynodon dactylon (L.) Pers. x Cynodon transvaalensis Burtt-Davy (Cynodon hybrid) and Paspalum vaginatum O. Swartz (seashore paspalum) cultivars suitable for golf or lawn bowls use. The end result provides superintendents and greenkeepers with additional knowledge to accompany their skills in managing or upgrading their greens to produce a denser, smoother and faster putting or bowls surface. However, neither turfgrass selection nor finely tuned management program will overcome unrealistic expectations (especially in relation to usage), poor growing environments, or limitations due to improper construction techniques.