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Some leafmining fly species are pests of agricultural and ornamental plants but they also include many species with little economic importance. The taxonomy of leafmining flies is often challenging because of putative cryptic species. Following new outbreaks of Liriomyza (Diptera:Agromyzidae) in Australia, we here characterize 13 dipteran leafminer species collected from Australia based on cytochrome c oxidase subunit 1 (COI) DNA barcodes, and we compare these with overseas data. We confirm barcodes of nine species from the Agromyzidae (Liriomyza sativae, L. huidobrensis, L. trifolii, L. bryoniae, L. chinensis, L. brassicae, L. chenopodii, Phytomyza plantaginis and P. syngenesiae) and one species from the Drosophilidae (Scaptomyza flava); we describe new haplotypes for some of these species. Furthermore, we provide the first DNA barcodes for two species (Cerodontha milleri and Phytoliriomyza praecellens) from the Agromyzidae and one species (Scaptomyza australis) from the Drosophilidae. These findings provide a baseline for DNA-based identification of pest Liriomyza incursions spreading across the Australian east coast in relation to other species already present in Australia.

We determined the host range of the parasitoid Trichomalus perfectus (Walker), a candidate for classical biological control of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), an important pest of canola in Canada. Studies were conducted in Europe and in North America. In laboratory experiments, the levels of parasitism (acceptance) of Ceutorhynchus turbatus Schultze, C. cardariae Korotyaev, C. omissus Fall and C. querceti (Gyllenhal) by T. perfectus were not significantly different than of the target host C. obstrictus. Although C. typhae (Herbst), C. pallidactylus (Marsham), C. americanus Buchanan, C. neglectus Blatchely and Ceutorhynchus sp. nr. nodipennis were parasitised by T. perfectus, the levels of parasitism were significantly lower on these species than on C. obstrictus. Ceutorhynchus peyerimhoffi Hustache, C. erysimi (Fabricius), C. alliariae H. Brisout, C. roberti Gyllenhal, Mogulones borraginis (Fabricius), Mononychus vulpeculus (Fabricius) and the leaf-mining fly Scaptomyza flava ...

Populations of the leafminer, Scaptomyza flava, were monitored fortnightly in turnip plantings at Pukekohe, south Auckland, for more than 2 years. The fly, and its main parasitoid, Asobara sp. (nr. persimilis) (Hymenoptera: Braconidae), were present throughout the year, with populations peaking in midsummer on spring plantings. A replicated field trial, comparing four planting dates, suggests that new leaves on young plants and on flowering stems were favoured for oviposition by the leafminer. In another experiment, young leaves of flowering Gypsophila sp. were more suitable for oviposition and larval survival than leaves of younger non-flowering plants. Measurements of the mandible and associated skeleton confirmed the existence of three leafminer larval instars. The parasitoid has a partial winter diapause. In midsummer, it achieved over 80% parasitism. A survey found Asobara parasitism of S. flava was restricted to a small area of south Auckland. These data, together with its monophagy in New Zealand a...

European leafminer, Scaptomyza flava (Fallen), is an important pest of brassicas, peas and gypsophila in New Zealand. This study examined the mating behaviour of this species for the first time under laboratory conditions. Males were the active sex in the entire mating behavioural sequence involving approaching, courting and mounting females, and copulation. Copulation lasted for about 20 min. There was no significant difference in pre- courtship, courtship and mating durations between virgin and mated males. However, mated males were significantly more likely to perform courtship and to achieve mating than virgin ones. It is suggested that males learn from mating experience, which helps them achieve higher mating success. Both virgin and mated males tended to disrupt mating couples but could not separate them.

The European leafminer, Scaptomyza flava, is an important pest of brassicas, peas and gypsophila in New Zealand. The patterns of S. flava adult eclosion, mating and oviposition were determined in the laboratory. Most adults (97%) emerged in the photophase with maximum adult eclosion occurring between 2 and 3 h into the photophase. Mating took place exclusively in the photophase and peaked about 30 min after lights on. Both male and female S. flava mated more than once. Females started oviposition 3 days after emergence, and the fecundity (number of eggs laid) and fertility (number of eggs hatched) peaked between 5 and 10 days after emergence. The mean lifetime fecundity was 133.5±4.1 eggs with the fertility rate being 57% during the 40-day oviposition period.

The leaf miner, Scaptomyza flava (Diptera: Drosophilidae), can damage Asian brassicas. Methods of control are required that are compatible with biological control of the lepidopteran pests that also damage this crop. Laboratory bioassays compared the susceptibility of adult flies and first instar larvae in leaf mines to 12 insecticides registered for use on brassicas and the insecticide abamectin. The efficacy of seven insecticides were compared in two field trials with Joi Choi and Pak Choi, and the survival of a larval/pupal parasitoid, Asobara persimilis (Hymenoptera: Braconidae) was assessed. Adult and larval flies were susceptible to nine insecticides. In the field trials, abamectin, deltamethrin, endosulfan and fipronil gave good control of fly larvae. Parasitoids emerged in treatments where fly larvae survived to pupate, i.e. abamectin, endosulfan, maldison, spinosad and indoxacarb.

Mined leaves were sampled from unsprayed sites in Victoria to record the range of leafminers and their parasitoids. Three agromyzid leafminers, Liriomyza brassicae (Riley), Liriomyza chenopodii (Watt) and Chromatomyia syngenesiae Hardy, and one drosophilid leafminer, Scaptomyza flava (Fallen), were collected, along with 15 parasitoids, mainly Eulophidae. The most common parasitoids were Hemiptarsenus varicornis (Girault) (42.5%), Diglyphus isaea (Walker), 14.6%, Closterocerus mirabilis Edwards & La Salle (10.5%), and Opius cinerariae Fisher (8.5%). Most parasitoids were collected from two or more leafminer hosts. Weekly collections from Chinese cabbage (Brassica rapa var. pekinensis) infested with L. brassicae and S. flava, and beetroot (Beta vulgaris var. crassa) infested with L. chenopodii were made over two seasons at Knoxfield, Victoria to assess the relative impact of these parasitoids on agromyzid fly populations in crops. A further two parasitoid species were identified at low densities. Hemiptarsenus varicornis and D. isaea were the most numerous parasitoids collected in both crops. A different sampling method in the second year showed that O. cinerariae made up 25% of the sample from Chinese cabbage and was probably more common than estimated in the first season. Control exerted by local parasitoids was high, with 100% control of L. chenopodii reached in beets within 1–3 weeks of mines appearing and 100% control of L. brassicae within 6 weeks.

Plant-herbivore interactions have evolved in the presence of plant-colonizing microbes. These microbes can have important third-party effects on herbivore ecology, as exemplified by drosophilid flies that evolved from ancestors feeding on plant-associated microbes. Leaf-mining flies in the genus Scaptomyza, which is nested within the paraphyletic genus Drosophila, show strong associations with bacteria in the genus Pseudomonas, including Pseudomonas syringae. Adult females are capable of vectoring these bacteria between plants and larvae show a preference for feeding on P. syringae-infected leaves. Here we show that Scaptomyza flava larvae can also vector P. syringae to and from feeding sites, and that they not only feed more, but also develop faster on plants previously infected with P. syringae. Our genetic and physiological data show that P. syringae enhances S. flava feeding on infected plants at least in part by suppressing anti-herbivore defenses mediated by reactive oxygen species.

Synthetic herbivore-induced plant volatiles (HIPVs) attract arthropod natural enemies showing potential for enhancing biological control. However, HIPVs can also affect the behavior of arthropod herbivores and possibly higher-order natural enemies, potentially complicating the use of HIPVs in biological control. The aim of our work is to understand the effects of one HIPV on the abundance of arthropods at three trophic levels. Of particular interest are effects on herbivores and enemies of natural enemies. A field experiment was carried out in turnip Brassica rapa L. (Brassicaceae) (cv. Green Globe). A randomized block design was used with a treatment of synthetic methyl salicylate (MeSA), and a control consisting of the crop alone. Yellow sticky traps were used for sampling aerial brassica pests, their natural enemies and fourth trophic-level natural enemies within the crop. Our results showed that the abundance of the diamondback moth parasitoid, Diadegma semiclausum Hellén (Hymenoptera: Ichneumonidae), the brassica leafmining pest Scaptomyza flava Fallén (Diptera: Drosophilidae), and the lacewing parasitoid, Anacharis zealandica Ashmead (Hymenoptera: Figitidae), increased significantly in the MeSA-treatment compared with the controls. Significantly more D. semiclausum females were attracted to MeSA than were males. However, it still remains unclear whether it is MeSA and/or volatiles produced by induced host plants that are attractive to the arthropods. These results are highly relevant to potential future application of HIPVs in pest management, as the attraction of arthropods within ‘untargeted’ trophic-levels may disrupt trophic cascades and challenges the ideas that the deployment of synthetic HIPVs in pest management may enhance biological control. Refereed/Peer-reviewed

Scaptomyza flava (Diptera Drosophilidae) known as European leaf miner has recently been identified as the pest species causing major damage to seed and other brassica crops grown in the South Island This pest is particularly damaging to hybrid Asian brassica seed crops but is also a major pest of seedlings of radish turnip and broccoli plants A larval/pupal parasitoid Asobara persimilis (Hymenoptera Braconidae) is an effective natural enemy of S flava at Pukekohe at certain times of the year A project funded by MAF Sustainable Farming Fund involves massrearing the parasitoids in Auckland and releasing them in unsprayed brassica crops in Canterbury and North Otago A total of 6550 pupae and 760 emerged adults were released over fortnightly periods at 46 sites from October 2010 to April 2011 The pupae included about 80 parasitised pupae and 20 that were unparasitised as a source of hosts for emerging parasitoids Overwintering surveys and further releases are planned for 2011/12 to try and establish this natural enemy as part of the ongoing development of IPM tools for seed forage and vegetable brassica crops grown in the South Island