The carob moth, Ectomyelois ceratoniae, is thought to originate from the Middle East, where it is a commercial pest of dates, almonds, pistachios and pomegranates. In California it is a pest of almond, date, pistachio and pomegranate. In Israel it is a pest of almonds, carobs, citrus and date palm. It is known as a pest of citrus, dates, figs, carob and almonds in Mediterranean countries and in WA, attacks almonds, apples, carob, oranges, figs and pomegranates. It is a major pest of almonds in Australia, and will also attack stored fruits and nuts.
- The greyish adult moth has a body length of 8-10mm, and a wing span of 20mm. The grey front wings have a wavy dark line, and the rear wings are white-grey with light-brown veins.
- In spring, the female moth finds suitable fruit or nuts on which to lay her eggs.
- As the larvae are unable to penetrate undamaged fruit and nuts, females seek out hosts that have been injured or already infested. Summer rains, which result in cracking and fungal infections, result in increased carob moth infestations.
- Eggs are laid on damaged carob pods (green and brown) as long as the temperature is favourable.
- Eggs (0.75mm long) are white when first laid, turning deep pink before hatching. The eggs hatch in 3–7 days.
- The larva is white or pinkish with a black head, with dark markings behind the head and tiny dark-brown bumps on its back. Growing up to 20mm, the larvae may be confused with that of the codling moth. After hatching, larvae feed until fully grown (20mm long). Cool weather in winter is thought to induce diapause (a period of suspended or retarded development) in larvae.
- The brown pupa is approximately 12mm long.
- Pupation can occur inside the pod; under the bark of trees, or under litter on the ground.
The entire life-cycle takes 32-43 days depending on temperature, with adults living for 5-10 days and females laying up to 200 eggs during their lifetime. There can be as many as four generations of carob moth a year– one from overwintered larvae, one from spring oviposition and 1-2 from summer oviposition.
- Carob pods become vulnerable to attack as soon as the green hulls begin to split, though larvae may also feed on ‘clean’ carob pods. Stored carobs are also vulnerable to carob moth.
- Navel oranges are the most commonly attacked citrus fruit in WA, and larvae usually bore into the navel end causing premature ripening and fruit drop. In grapefruit, eggs are laid under the calyx.
- Other fleshy fruits are damaged by the larvae feeding on the seeds or near the stone.
- In stored nuts and fruits, damage caused by the carob moth can resemble that caused by several other superficially similar insects. For example, several species of moth attack stored nuts are may be confused with carob moth.
- If nuts are to be stored for a period, they should be heat treated before storing in insect-proof containers. During hot summer weather, spreading the material thinly on an iron tray and placing it in the sun for several hours will also kill the pests. Smaller quantities can be stored in the fridge or freezer. To heat treat harvested nuts, place them in an oven and slowly increase the temperature to 55-60°C and keep the nuts in the oven at that temperature for one hour.