Euproctis fraterna, Maldives Minimize

February 2006. A caterpillar on Terminalia cattappa on Baa atoll, Maldives. A resort there has suffered two serious infestations over the past month, with hotel guests and staff experiencing intense itching upon contact with the caterpillars. This represents a very real problem and the resort would like to know a suitable (preferably non-toxic) control method.

It was said to be Euproctis fraterna (in Dhivehi it is known as 'huvani'), a lymantriid, and is a recurrent problem in Maldives, outbreaking on the atolls at various times, the reason for which is unknown. Generally, such outbreaks are caused by disturbances of the ecosystem, such as prolonged droughts, cyclones, etc. Island councils or the government hire specialists to spray pesticides, but it is nearly always too late to prevent the outbreak as applications only start when the outbreak is noticed and the problem has already commenced. The outbreaks do not last long, but can be quite serious, with people being forced to leave their homes and some even being hospitalised.

In general, there is little one can do, although regular monitoring of the pest may give some clues as to when populations are increasing, which may lead to the development of suitable preventative actions.

In a short study on this pest for the Ministry of Agriculture 2 years' ago, three parasitoids were found that attack various developmental stages of the caterpillar, but these are, of course, also killed by pesticides (although Bt would be a suitable choice).

There are similar species in New Guinea, and it is very similar to a species (Euproctis lutea) on Barringtonia  in Darwin, Australia. The larvae of this species causes severe skin urtication. Unusually, the moths also cause urtication, presumably from hair like scales that the female uses/loses to cover egg masses during oviposition. The skin irritation is spread further by scratching or by the movement of clothes if a moth goes down the back of the shirt, etc.