Adult gall midge flies, Feltiella acarisuga are small about 1.5 to 2 mm long pinkish brown colored, short-lived flies. Adult gall midge flies generally do not feed on mites but all of their larval stages are predatory in nature and feed on all the stages of pest mites. Females lay about 30 to 40 shiny eggs in the colony of pest mites. Depending upon optimum temperature and relative humidity, eggs hatch into small larvae in a couple of days after deposition. The hatched larvae are brown in color. Immediately after hatching from eggs, larvae start feeding on the immature stages and eggs of pest mites especially two spotted spider mite, Tetranychus urticae. Spider mites are serious pests of many greenhouse and field crops. While feeding, larvae of midge fly develop through four developmental stages/instars. The matured 4th instar larvae generally pupate in silken cocoons on underside of the leaves and emerge as adults after 7-10 days of pupation and life cycle continues.
- - Effective against the following pests
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- Two spotted spider mite, Tetranychus urticae
- Brown almond mite, Bryobia rubrioculus
- Carmine spider mite, Tetranychus cinnabarinus
- European red mite, Panonychus ulmi
- + Key factors for Feltiella acarisuga effectiveness
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- Adult midge flies can actively search for pest mite colonies to lay eggs.
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Feltiella acarisuga larvae can feed voraciously on all the stages of spider mites.
- Newly hatched young larvae can find its victims quickly and feed on them.
- Single Feltiella acarisuga larva can eat more than 15 adults, 50 eggs, 25 nymphal stages of pest mites.
- This predatory insect is very easy to release in the greenhouses.
- These predatory flies perform better against pets mites when optimum temperature is between 68°F(20°C) and 86°F (27°C) and relative humidity is between 70 and 90%.
- + How predatory Feltiella acarisuga gall midge works in the field
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- Midge flies (Feltiella acarisuga) are supplied as pupae on leaves in a container.
- When pupae or adults that are already emerged from pupae during transit are released in the greenhouses, adults emerging from these pupae will fly away from the containers and actively start searching host mite colonies to lay eggs.
- Once pest mite colonies are found gall midge fly females lay eggs in the or near the mite colonies.
- Depending upon temperature, these eggs hatch into tiny larvae within a week.
- Immediately after hatching from eggs, tiny larvae start feeding on all the developing stages (eggs, nymphs and adults) of pest mites including two-spotted spider mites.
- As gall midge fly larvae are voracious feeders, they can suppress over 40% population of pest mites (Sharaf 1984) in a very short period of time.
- + Which stages of pest mites are killed by predatory gall midgeFeltiella acarisuga?
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- Eggs of mites
- Nymphs of mites
- Adult mites
- + How many Feltiella acarisuga predatory gall midge flies should be released?
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- To build up population of gall midge flies in the targeted areas, release about 2-3 flies per 50 square foot area (4.65 square meter area) every week for 4 weeks.
- To achieve better control of mites in a large area, release 200- 800 gall midge flies per hectare (2.5 acres) weekly for 4-5 weeks.
- + When and how Feltiella acarisuga predatory gall midge flies should be released for the effective control of mites?
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- Adults of gall midge fly should be released when there is a heavy infestation of mites.
- These flies are supplied in a containers as pupae on the leaves. During transit adults can emerges from pupae.
- When package is arrived and if you are ready to release midge flies, make sure the lids of containers are perforated to allow gall midge fly adults to escape.
- It is recommended to release gall midge flies immediately upon their arrival by placing the perforated containers at different places in the greenhouses or gardens.
- If you are not ready to release these predatory flies, store them in a dark place at cooler temperatures at 10-15°C or 50-59°F for only a couple of days.
- + Why you need them
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- they can reduce the crop damage by feeding on the eggs nymphs and adults of pest mites
- they are able to actively search for their host, the different species of mites
- they can reproduce and continue their life cycle in the garden after first application
- they are commercially available and easy to release in the greenhouses or fields
- + Why they are safer than traditional pesticides
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- they do not damage plants
- do not cause any harm to the personnel involved in their production and application
- food products are safe to handle and eat when they are treated with predatory gall midge fly
- they do not harm humans, animals and pollute the environment
- + Research Papers
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- Gillespie, D.R., Opit, G. and Roitberg, B. 2000. Effects of temperature and relative humidity on development, reproduction, and predation in Feltiella acarisuga (Vallot) (Diptera : Cecidomyiidae). Biological Control 17: 132-138.
- Mo, T.L. and Liu, T.X. 2006. Biology, life table and predation of Feltiella acarisuga (Diptera : Cecidomyiidae) feeding on Tetranychus cinnabarinus eggs (Acari : Tetranychidae). Biological Control 39: 418-426.
- Sharaf NS. 1984. Studies on natural enemies of tetranychid mites infesting eggplant in the Jordan Valley. Zeitschrift für Angewandte Entomologie. 98:527-533.
- Xiao, Y.F., Osborne, L.S., Chen, J.J. and McKenzie, C.L. 2013. Functional responses and prey-stage preferences of a predatory gall midge and two predacious mites with twospotted spider mites, Tetranychus urticae, as host. Journal of Insect Science 13: article number 8.
- Xiao, Y.F., Osborne, L.S., Chen, J.J., Mckenzie, C., Houben, K. and Irizarry, F. 2011. Evaluation of corn plant as potential banker plant for supporting predatory gall midge, Feltiella acarisuga (Diptera: Cecidomyiidae) against Tetranychus urticae (Acari: Tetranychidae) in greenhouse vegetable production. Crop Protection 30: 1635-1642.
