Primefact 1297, Second edition, May 2026
Spotted wing drosophila (Drosophila suzukii) is an exotic plant pest. This insect pest is a serious threat to Australia’s soft-skinned fruit industries, such as berry fruit, grapes and stone fruit.
Spotted wing drosophila is a tiny fruit fly (2-3mm), similar in size to vinegar flies which sometimes
gather around overripe fruit.
Notifiable status
Spotted wing drosophila (D. suzukii) is a notifiable plant pest in NSW.
All notifiable plant pests and diseases must be reported within 1 working day. You can report notifiable plant pests and diseases by one of the following methods:
- Call the Exotic Plant Pest Hotline 1800 084 881
- Email biosecurity@dpird.nsw.gov.au with a clear photo and your contact details
- Complete an online form
A full list of notifiable plant pests and diseases can be found in Schedule 2 of the NSW Biosecurity Act 2015.
Damage
Spotted wing drosophila (SWD) is a serious fruit pest because it attacks healthy ripening fruit as well as damaged or split fruit. Other Drosophila spp. fruit fly larvae feed only on rotting fruit. They reduce fruit yield and quality through direct feeding damage and by permitting secondary infection of the fruit.
Females prefer to lay eggs in ripe fruit (Figure 1) but will also lay eggs in unripe, overripe and damaged fruit.
The female penetrates the skin of soft-skinned fruit with a large, serrated ovipositor. Eggs are laid just under the skin of the fruit creating a small puncture or ‘sting’ on the fruit surface.
Affected fruit does not show obvious symptoms of infestation until the flesh starts to break down leading to discolouration. Symptoms of infestation include:
- Early mould, wrinkling and softening of fruit
- Soft spots and collapse of fruit
- Small holes in fruit, which may release juice or liquid
- White larvae noticeable in the rotting flesh (Figure 2).
Symptoms can appear in as little as little as 2-3 days after eggs are laid, depending on the host and environmental conditions.
Description
Adults: flies are 2–3mm long with a wingspan of 6–8 mm. Male flies are typically smaller than females. Adult flies have prominent red eyes, yellow-brown bodies, with black dark bands across the abdomen. Only male flies have a distinguishing single dark spot on the tip of each wing (Figure 3). Otherwise, SWD flies look almost identical to vinegar flies.
Female flies have a saw-like ovipositor which can be seen when extended and is used to puncture the skin of fruit for egg laying.
Eggs: 0.6 mm in length and are oval shaped and white in colour.
Larvae: white to cream in colour, cylindrical and about 3 mm long when fully grown (Figure 2).
Pupae: cylinder shaped, reddish-brown coloured and 2–3 mm in length. Pupae have two small projections on one end which are used for breathing.
Lifecycle
Female flies lay eggs in soft-skinned fruit; the eggs hatch and the larvae develop and feed inside the fruit. SWD reproduces extremely quickly, with females capable of producing more than 5 eggs per day, and more than 600 over their lifetime. Development can take as little as 12 days but is influenced by factors such as temperature and host species. It is multivoltine, completing several generations per year.
SWD overwinter as adult flies which then become active as temperatures rise, although under some conditions they may be active year-round.
Larvae develop through three larval instars.
Eggs, larvae and pupae all vary in developmental time depending on environmental conditions. Generations over the summer months have the shortest development time.
Host range
Fruit crops affected by SWD include berries (blackberry, blueberry, boysenberry, cranberry, loganberry, raspberry and strawberry), stone fruit (apricot, cherry, peach, plum, prune and nectarine) and grapes. Apples, pears and other fruit with thicker skins are also affected if the skin is already broken and fruit has started to rot.
Preferred hosts are all softer-fleshed fruit.
Distribution
SWD is not present in Australia.
SWD is originally from southeast Asia and is widely distributed across Asia. It has a restricted distribution in India and Pakistan and has since spread to Central and South America, Hawaii, North America, the United States and European countries of France, Italy and Spain.
Spread
SWD can only fly short distances, being capable of dispersing approximately 9 km over the span of a single generation. The primary form of long-distance dispersal is via human assisted movement of larvae-infested plant material, which has been the primary mechanism for international spread.
Actions to minimise risks
Put in place biosecurity best practice actions to prevent entry, establishment and spread of pests and diseases:
- practice “Come clean, Go clean”
- ensure all staff and visitors are instructed in and adhere to your business management hygiene requirements
- source propagation material of a known high health status from reputable suppliers
- monitor your fruit crops regularly
- keep records