Almond moth

The almond moth or tropical warehouse moth (Cadra cautella) is a small, stored-product pest. Almond moths infest flour, bran, oats, and other grains, as well as dried fruits.[1] It belongs to the family of snout moths (Pyralidae), and more specifically to the tribe Phycitini of the huge snout moth subfamily Phycitinae. This species may be confused with the related Indian mealmoth (Plodia interpunctella) or the Mediterranean flour moth (Ephestia kuehniella), which are also common pantry pests in the same subfamily.[2]

Other common names, particularly in nonbiological literature, are dried currant moth and fig moth, which invite confusion with the close relatives Cadra figulilella (raisin moth) and Cadra calidella (dried fruit moth). Like the raisin moth, the almond moth has achieved an essentially cosmopolitan distribution due to inadvertent transport with food products in its larval form. Adults live for about 10 days after eclosion and do not eat, but may drink if water is available. The mating system is polygamous; however, many females will only mate once.

Adult almond months are predominantly light brown in color, with smaller hind wings that are typically gray. When extended, its wingspan ranges from 14–22 mm. The back edges of the wings are lined with a short fringe.[3]

Almond moth larvae are mostly gray with darker heads. The caterpillar is 12–15 mm long and identifiable by the pattern of spots along its back.[3]

Geographic range

Almond moths are found around the world. Although it thrives best in tropical climates, it has spread to many regions around the globe due to its tendency to infest dry goods that are shipped internationally.[3] For example, it has been transported across Polynesia with copra shipments.[4]

As almond moths exists primarily as a pest, its habitat is often some kind of dry food product which is stored in a warehouse or similar industrial environment. Most commonly, they are found in dried fruits, but they have also been found in nuts, beans, flour, and other grains.[3]

Larval almond moths are hatched onto a variety of dry food products, which then serve as their primary food source. Although the moth infests several different kinds of food, the larvae develop most rapidly on wheat-based products.[5] Moreover, cracked or ground seed and grain products are more ideal for larvae than whole seeds or grains because the larvae are unable to penetrate shells or hulls, which makes feeding more difficult.[6] The caterpillars are cannibalistic; larvae will also eat eggs and other smaller larvae.[7]

Generally, adult female moths will oviposit around 200 eggs at a time. The timing and number of eggs oviposited has been shown to vary based on several factors, including temperature, humidity, access to water, and type of food source. Low temperatures delay oviposition, and low humidity or lack of access to water seems to reduce the number of eggs oviposited by any given female.[3] Preferred food source upon which to oviposit may vary with the strain of almond moth.[9] Typically, females will oviposit at night.[10]

The almond moth thrives best in warm, humid environments. The ideal temperature range for development is 30-32 degrees Celsius (86-90 degrees Fahrenheit), and the ideal humidity range is 70-80%.[5] In optimal conditions, it takes about three and a half days for eggs to hatch, and the larvae go through five instars over a period ranging from 17–37 days.[7] The pupal stages lasts around seven days in optimal temperature and humidity.[3] Adult females live on average for ten days and adult males live for an average of six to seven days.[8]