Parasitism and phenology of Dasineura mali (Diptera: Cecidomyiidae) in Canadian apple (Rosaceae) orchards

The apple leaf midge, Dasineura mali (Kieffer) (Diptera: Cecidomyiidae), an invasive alien pest established for many years in Nova Scotia, Canada, has invaded Ontario and British Columbia, Canada apple (Malus domestica Borkhausen; Rosaceae) orchards, damaging growing tips of trees. Molecular analysis indicated that Nova Scotia populations are genetically different from Ontario and British Columbia populations. Pheromone trap captures, oviposition on growing apple terminals, and the incidence of third instars indicate three D. mali generations in each province. Platygaster demades Walker (Hymenoptera: Platygastridae), released in Nova Scotia in 1993, parasitised 34% of the third midge generation in that province and was reared from D. mali for the first time in 2016 in the Fraser Valley of British Columbia. Lyrcus nigroaeneus Ashmead (Hymenoptera: Pteromalidae) parasitised up to 21% of D. mali in southwestern Ontario. Synopeas myles (Walker) (Hymenoptera: Platygastridae) was recorded from D. mali for the first time, one specimen in each of Nova Scotia and Ontario, and was the most important parasitoid in British Columbia. Synopeas myles parasitism in Okanagan and Similkameen, British Columbia orchards increased from 0% to a mean of 30% of D. mali larvae from 2014 to 2016. Other minor parasitoids included Platygaster tuberosula Kieffer (Hymenoptera: Platygasteridae) in all three provinces and Aphanogmus vicinus Förster (Hymenoptera: Ceraphronidae) in British Columbia.

Developing apple leafcurling midge rearing techniques

Apple leafcurling midge (Dasineura mali; ALCM) is considered a quarantine pest in some of New Zealand’s valuable export markets. Research into alternatives to methyl bromide as a fumigant requires a mass rearing programme to provide large numbers of all life stages. Our aim was to focus on developing an understanding of the environmental conditions that break ALCM diapause and facilitate ALCM oviposition. A trial was conducted comparing ALCM oviposition rates on apple seedlings in a controlled temperature room versus a shade house in ambient conditions over the summer months. Additionally, long day length and high humidity conditions were tested to break the diapause of ALCM cocooning larvae. Oviposition rates on young apple seedlings were similar in the controlled environment room and the shade house; however, apple seedlings grew better in the shade house due to lower incidence of powdery mildew. Adults emerged from ALCM cocoons that had been in diapause for five months and then held at 20.9°C for seven days. Conditions to break ALCM diapause have been determined. Seedlings at the six- to eight-leaf stage have the potential to provide an oviposition substrate. Further investigations are required into artificial oviposition substrates and the development of a larval diet to mass rear ALCM larvae.

Effect of various heat treatments to target apple leafcurling midge (Dasineura mali) cocoons on apples

New Zealand apples infested with apple leafcurling midge (ALCM) cocoons are a quarantine issue for growers exporting to many markets. The presence of ALCM on apples in these markets requires fumigation with methyl bromide, which decreases fruit quality. The effectiveness of various forms of heat treatments on ALCM were evaluated as alternatives. Apples infested with ALCM cocoons were subjected to one of the following heat treatments: Controlled Atmosphere Temperature Treatment System (CATTS; 1% O2, 15% CO2, 46˚C, 3 h), hot air (46˚C, 3 h), hot water high pressure washing (hot-HPW; 55˚C, 100 psi, 15—20 s), or hot water drench (HWD; 55˚C, 40 psi, 15—20 s). ALCM removal and mortality were assessed 7-days post-treatment. The hot-air and CATTS treatments provided the greatest control, with 82.2 and 92.2% mortality respectively. More cocoons were removed with hot-HPW (46.6%) compared with ambient-HPW (27.1%). Neither HWD nor hot-HPW increased mortality of cocooned ALCM over that in untreated controls. ALCM cocoons are particularly difficult pests to remove/kill; further research should focus on incorporating multiple control measures into the current systems approach.

Gall midges Cecidomyidae (Diptera) common in Ukraine, their trophic connections and harmfulness

Information is given on the common cecidomyiidae phytophagous cultures in agricultural crops. The morphological signs, biological features of development, trophic bundles of gallstones are indicated. Characterization of the most harmful species is Mayetiola destructor Say, Sitodiplosis mosselana Gehin, Stenodiplosis panici Plotn., Contarinia tritici Kirby, C. Medicagine Kieffer, C. pisi Winnertz, C. pyrivora Riley, Dasineura floralis Maric., Dasineura mali Kieffer, D. pyri Bouche D. Obtain Rubs., D. ribis Barnes, D.plicatrix Loew., Thomasiniana oculiperla Rubs., T. ribis Marik., Lasioptera rubi Schrank. Covered periods of their development and harmfulness. Described are characteristic signs of damages by cerebellum corn and leguminous cultures, perennial legumes and fruit and berry plantations.

Annual and regional variability in adult Dasineura mali (apple leafcurling midge) emergence in New Zealand

Apple leafcurling midge is an important quarantine pest for New Zealand apple exports. Season-long pheromone trapping was conducted in Hawke’s Bay and Nelson from 2004—2017, and from 2012—2017 in Central Otago. Four generations occurred annually in Hawke’s Bay and Nelson and 3—4 in Central Otago. In Hawke’s Bay and Nelson, the timing of each peak varied by about 3—4 weeks between years, while the difference was ~2—3 weeks in Central Otago during fewer years of monitoring. Hawke’s Bay was up to a month earlier than Central Otago for the same peak within individual years. The major factor behind this variability was the accumulated number of growing degree-days. Insecticide sprays target midge larvae, but are timed against the second and third peaks of adult emergence. Variations in the timing of these peaks annually and across the main pipfruit growing regions, mean that specific insecticide timing recommendations are necessary each year for each region.

Development of a ‘lure and kill’ technique for apple leafcurling midge, Dasineura mali

Apple leafcurling midge (ALCM) is an important quarantine pest of New Zealand apples. Current methods for ALCM control have difficulty meeting the strict phytosanitary standards of some export markets. ‘Lure and kill’ is a new strategy against this pest, in which males are attracted to an insecticide-treated substrate where they collect a lethal dose. Trials were conducted using a gel matrix “Specialized Pheromone & Lure Application Technology” (SPLATâ„¢) to dispense and release the ALCM sex pheromone and the insecticide permethrin. Lures using SPLATâ„¢ were placed within plastic cylinder traps that collected the dead midges so they could be counted to determine treatment efficacy. The size, shape and age of SPLATâ„¢ spots influenced midge catches. Higher catches occurred with spots having a larger quantity of pheromone, greater surface area of SPLATâ„¢, or with fresh material. The implications for the development of a lure and kill strategy for ALCM are discussed.

Predation of apple leafcurling midge Dasineura mali by Sejanus albisignata

The predatory mirid bug Sejanus albisignata has been observed feeding on apple leafcurling midge (ALCM) eggs but quantitative data on its potential as a predator of ALCM are lacking Two methods were trialled to assess predation of ALCM by S albisignata In a laboratory experiment apple shoots infested with freshly laid ALCM eggs were contained with and without a S albisignata adult and in a field experiment paper bags were secured over shoots with ALCM eggs and individual S albisignata nymphs were introduced into half of these There were significant reductions of surviving midge larvae on shoots confined with adult predators and reduced numbers of midgeinfested leaves and larvae on bagged shoots with S albisignata nymphs Results from these nonchoice trials indicate that S albisignata can be an effective predator of ALCM More detailed feeding studies would determine if adult and immature S albisignata have a preference for midge eggs or larvae

Sejanus albisignata its potential contribution towards apple leafcurling midge (Dasineura mali) biological control in Hawkes Bay orchards

Predation has been proposed as one of the possible reasons for the decline in apple leafcurling midge (ALCM) activity and damage observed in Hawkes Bay orchards in recent years Sejanus albisignata is a generalist predator and commonly found in apple orchards To establish if there is any relationship between ALCM and S albisignata populations of both species were monitored during 201112 on four apple orchards in Hawkes Bay Nymphs and adults of S albisignata were counted on 100 ALCM infested shoots per orchard at weekly intervals Sex pheromone traps were used to monitor numbers of male ALCM weekly throughout the season in the same orchards Sejanus albisignata and ALCM activity was well synchronized with the timing of generations one two and three of S albisignata coinciding with the second third and fourth generations of ALCM There was also a significant positive correlation between the numbers of S albisignata in each generation and the number of ALCM males trapped for each of the corresponding ALCM generations These relationships suggest that S albisignata may contribute towards ALCM control but further studies of their feeding behaviour and numerical responses are required to determine its actual contribution towards biological control of ALCM