Ramie moth, banana moth (name given in this fact sheet). The name ramie is a common name for the main host, Boehmeria nivea.

Arcte coerula; previously, Cocytodes coerulea. It is a member of the Noctuidae.

Asia, Oceania. It recorded from Australia (Queensland and Norfolk Island), Fiji, and Papua New Guinea.

Boehmeria species, e.g., Bohmeria nivea (ramie), Boehmeria nipononivea (Japanese false nettle), Boehmeria australis (nettle tree), and others in the nettle family (Urticaceae), Cypholophus, Debregeasia, Girardinia, and Pipturus). Ramie is also called China grass or white ramie in China.

Ramie is an important natural fibre crop (used to make cloth, ropes, and high-quality clothes), grown in China, India, Southeast Asia and Pacific rim countries. However, it is also rich in protein, and the shoots and leaves can be used as fodder for cattle and geese. In Fiji, it has been recorded on bunches of over-ripe bananas.

The caterpillars or larvae do the damage by defoliating plants. Early stages feed together making holes in the leaves (Photos 1&2), later ones strip the leaves leaving only the major veins (Photo 3).

Eggs are laid on the underside of Boehmeria leaves. The mature larvae are yellow with a wide black band along each side containing a row of red spots, and narrow black lines across the back (Photos 4&5). The head and legs are black. Sparse, stiff long white hairs cover the body. When threatened, the larvae swing the front part of the body from side to side. The caterpillars darken with age, and grow up to 10 cms.

The adult moth has dark brown forewings with black and silvery markings, and light brown patches at the tips (Photo 6). The hindwings are brown with wide blue spots or lines (Photo 7). The adult moths are attracted to ripe fruit of plantains (Photo 8).

In China, the ramie moth is said to be a destructive pest, causing severe destruction.

Look for large vibrant yellow and black larvae perforating leaves of Boerhmeria when young and stripping all but the main veins when old. Look for dark moths with brown tips to the forewings, and distinctive blue patterns on the hindwings.

There is very little to report on the management of this pest, except for the use of pesticides. No natural enemies have been reported. The cultural control recommendations are those that are standard for moth larvae.

CULTURAL CONTROL

Before planting:

• Avoid overlapping crops of Boehmeria (ramie).
• Avoid planting new crops next to old where the larvae are present.
• Leave at least 3 month between crops.

During growth:

• Visit the crop frequently and regularly: twice a week is recommended, to check if there are caterpillars attacking the leaves. If found, do the following:
  • Check the young leaves, and those where only the veins are left. Look for faeces on the leaves. They are the signs that caterpillars are present.
  • Hand remove the larvae if only a few are present, and the area of the planting is small; if the area is large or if the infestation of larvae is high, consider using a pesticide. But consider carefully which ones to use.

After harvest:

• Collect and burn or bury as much of the crop as possible.

CHEMICAL CONTROL

• Use botanical insecticides (see Fact Sheet no. 56), such as, neem, derris, pyrethrum and chilli (with the addition of soap), or microbial, commercial, products that contain disease-causing organisms, such as spinosad (Success) and Bt - Bacillus thuringiensis subspecies kurstaki.
• Synthetic pyrethroids are likely to be effective, but will also kill natural enemies (although none have yet to be reported).

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Note, derris (Derris species) contains rotenone, an insecticide, often used as a fish poison; it should be used with caution. The commercial derris insecticide is made from Derris elliptica.
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When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval. Recommendations will vary with the crop and system of cultivation. Expert advice on the most appropriate pesticide to use should always be sought from local agricultural authorities.