peach fruit fly (Bactrocera zonata)

Symptoms

Larger than Mediterranean fruit fly (8–10mm), distinctive orange-brown body with dark wing pattern, larvae bore deep into pomegranate, mango, peach, citrus; rapid fruit decay.

Plants affected

• pomegranate

Easily confused with

• Mediterranean fruit fly

  How to tell them apart: Both are fruit flies whose maggots tunnel inside pomegranate fruit, so the fruit damage alone (sting punctures, internal rot, premature drop) cannot tell them apart — you must look at the adult fly on or near the fruit. Bactrocera zonata (peach fruit fly) is a slender wasp-like fly with a largely reddish-brown to orange-brown abdomen, clear wings with only a narrow dark stripe along the front edge and at the tip, and a bright yellow band across the thorax; it lacks bold spotted wings. Ceratitis capitata (medfly) is smaller and stouter with a mottled, banded wing pattern showing distinctive grey, yellow and brown bands/blotches, a pale yellowish-fawn body with silvery and black markings on the thorax, and the male has two diamond-tipped black bristles on the head. If you find the reddish-brown clear-winged fly (B. zonata), treat it as the quarantine species and report it.

• carob moth (pomegranate fruit borer)

  How to tell them apart: Look for a tiny pin-prick 'sting' puncture on the smooth rind, often with a small darkened or sunken halo and sometimes a clear oozing droplet that dries to a brown spot. Cut the fruit open and you find legless, creamy-white maggots (pointed at the head, blunt at the tail) tunnelling through the wet, fermenting flesh, which turns into a soft watery rot with a sour smell. The adult is a slender amber-brown fly with banded clear wings, seen hovering around the fruit. There is no silk webbing and no caterpillar inside. Look for a larger ragged bore-hole, usually near the crown/calyx end, surrounded by reddish-brown frass (sawdust-like droppings) and fine silken webbing. Inside you find a true caterpillar with a distinct head capsule and legs, pinkish-grey to off-white, often actively wriggling, with dry crumbly excrement and webbed-together damaged seeds rather than a watery rot. The damage is drier and more 'chewed' looking, and you may see secondary mould (often dark/black) at the entry rather than a sour fermenting ooze. No clear single pin-prick sting mark.

Common questions

How do I recognise peach fruit fly (Bactrocera zonata) on pomegranate?

Larger than Mediterranean fruit fly (8–10mm), distinctive orange-brown body with dark wing pattern, larvae bore deep into pomegranate, mango, peach, citrus; rapid fruit decay.

Do I have to report peach fruit fly (Bactrocera zonata)?

Yes. peach fruit fly (Bactrocera zonata) is a regulated quarantine organism in the EU. A suspected finding must be reported to your national plant protection organisation — they will confirm it and tell you what to do next.

How is peach fruit fly (Bactrocera zonata) treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.