A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
February 2015. The NPPO Seychelles reported that there has been an outbreak of hairy caterpillars for the first time on three major islands of the Seychelles Archipelago, Mahe, Praslin and La Digue. Preliminary identification is Euproctis spp., possibly Euproctisfraternal (Lepidoptera: family Lymantriidae). The main concern is the use of pesticides. Pesticides are effective – they kill the caterpillars – especially pyrethroids, but the caterpillars remain hanging to the trees on silky threads releasing hairs, or setae, on the wind. A request was made to help with identification and control. If there any pheromone Seychelles would be grateful to know.
A member provided the following information:
The problem is very similar to those experienced from time to time in the Maldives. The identification of the caterpillar is probably correct. The outbreak is usually of short duration – a few months at most – but it causes major problems, especially to people. The ‘hairs’ on the caterpillars, and the scales on the wings of adult moths cause serious skin, eye and inhalation difficulties.
In the Maldives, Euproctis fraterna can reach outbreak levels after a period of prolonged drought. The plant hosts – which do not produce new foliage during droughts – rapidly recover producing new shoots which are ideal food for the young caterpillars. Also, the moths produced are much more fecund than those produced in ‘leaner’ times. The natural enemies are slow in catching up with increased population, hence in a few months you experience an outbreak.
During the outbreaks, pest control operators charge much for the application of pesticides to local tress (in Maldives the most affected were Terminalia spp., which also appear in the images). But in the Maldives, by the time the outbreak occurred it was usually under control ‘naturally’ by its natural enemies. Applying large amounts of pesticides thus risks prolonging the problem as these kill off the parasitoids.
There are 2 important questions:
Is this the first time Seychelles has experienced this problem, or has it happened in the past?
Is the outbreak country-wide or limited to one or a few islands.
There are several ways of preventing future outbreaks, although they won’t help with the present outbreak.
Monitor Euproctis populations – use lights traps and inspect some sentinel trees – especially after a long drought.
Any significant increases in the adults caught in the traps and the egg masses found on the trees may then lead to a decision to administer spot pesticide applications on the preferred host trees.
Check what natural enemies are already present (in the Maldives we found several egg and larval parasitoids) – and this is the best time to find that out.
Consider removing Terminalia trees from the main residential areas and beaches often visited by tourists and locals. This won’t be a popular move, but it might be the most effective in the long term. If this is a recurrent problem – and even if it’s the first time – it is likely that it will return!
In response, the Seychelles said that they are not using pesticide on a wider scale; pesticide spray is only used at schools; this has just started with spraying at weekends so that school programmes are not interrupted. In homes, bio-pesticides which have been tested and work well, such as Neemik, Nilinsect, Killpest and Neembaan, are recommended.
Parasitoids have been noticed with some larval stages dying at a young stage. Under the microscope small holes are seen on the back of the larvae.
Dave Britton at the Australian Museum looked at the images send and said: “Not sure about the identification on this one; the images of E. fraterna that I could find didn’t match the images of adult moths in the enquiry. The chances are that it is a species of Euproctis though, and they are notorious for urticating hairs. There are some equivalent pest moths with urticating hairs that might be useful sources of information, in particular the pine processionary moth, Thaumetopoea pityocampa, which is a major pest of pine forests in southern Europe. In those situations they often have to close off forests because of the hairs being blown around”.
Maybe some manual control methods could be possible, such as banding the base of trees with hessian bags, waiting for larvae to shelter under them, then destroying the larvae with boiling water or similar.
Seychelles: Biological Control Planned to Eradicate Hairy Caterpillar Pest in Seychelles
TBy John Lablache and Sharon Meriton-Jean
Victoria — The Seychelles authorities are intensifying efforts to fight an infestation of yellowish-black caterpillars with stinging hairs following the spread of the pest first reported in February.
The caterpillars have been observed in several regions and islands of the Indian Ocean archipelago including the northern part of Mahe Island, the most populated island of Seychelles, which is the most affected. Other islands such as Praslin, La Digue, Cerf and Moyenne have reported its arrival.
People have reported developing an itchy skin rash after coming in contact with its urticating hairs which may last several days and is treatable using antihistamines.
“We sent samples of the moths to several of our partners, including laboratories in La Reunion and also Australia. What they have confirmedis that this type of caterpillar is from the genus Euproctis. However, they could not identify the species,” said Randy Stravens, the Directorof Plant and Animal Health Services in the Seychelles Ministry of Fisheries and Agriculture, in a phone interview to SNA.
“The closest species to what we have sent to them that they could identify were Euproctis Fraterna, [brown coloured moth] and Euproctis Pectinata,” said Stravens, adding that this could be a new species or could have been around but have never been identified and recorded by anyone.
According to the islands’ Division of Risk and Disaster Management (DRDM) there is a coordinated eradication effort underway in the Indian Ocean country of 90,000, where there have been over 200 requests for assistance to deal with the infestation of caterpillars. This includes 16 schools that have been fumigated.
In a press conference on Friday, the DRDM, the Seychelles Agricultural Agency and the Ministry of Fisheries and Agriculture announced that an action plan costing about $219,000 is being proposed for government funding.
This eradication effort involves wide scale spraying with the bio-pesticide Bacillus Thuringengirensis, which is a naturally occurring bacterium that can infect and kill insects. The use of chemicalpesticides is being discouraged as this could destroy parasitoids or biological agents in the environment.
“While trying to eradicate the pest, we are also encouraging biological control,” said Stravens, who was also present at the press conference, adding that they are not considering other parasitoid at this stage.
“Until now, it has been found that mixing Javel [bleach] and water on a 1:3 ratio is rather effective, though this can only be used to a limited extent and covering only small areas,” he added.
Stravens said that one common reaction to the moth infestation has been cutting or burning down infected branches, which “unfortunately, this only causes the infestation to spread as the moths just fly elsewhere.”
He adds that although the hairy caterpillar feeds on the leaves of a dozen plants commonly found in Seychelles, including the mango and golden apple, it is more commonly found on the ‘Bodanmyen’, also known as Tropical Almond tree and on castor bean plants locally known as ‘Tantan’, both of which grow abundantly in coastal areas.
The Chief Executive of the Seychelles Agricultural Agency, Marc Naiken says the moth is not affecting fruits and vegetables of Seychelles and that though in some instances, the pest has been found feeding on leaves of some fruit trees, such as the mango, howeverfarmers have not expressed concern at this point in time.
He said the risk of such pests arriving in Seychelles in a dormant stage on ships is high.
Naiken said a new piece of bio-security legislation will be introduced soon which he hopes will have significant repercussions in controlling pests at points of entry, such as the port and airport.
Although it is not known how the caterpillar reached Seychelles, Euproctis Fraterna has been reported in the islands of the Maldives, situated to the north-east of the Seychelles archipelago.
According to Eco-Consult Pacific, a Fiji-based consulting group, the caterpillars and adult moths of Euproctis fraterna “regularly reach outbreak levels on the Maldives, when they can cause complete defoliation of native trees on some islands.”
The company sent a specialist on integrated pest management to the Maldives in 2004, where they faced outbreaks of large clusters of the caterpillars and assisted with the development of a control programme.
In 2006, another outbreak was reported in the Baa atoll of the Maldives.
Euproctis fraterna has also been reported in Madagascar, Sri Lanka, Pakistan, India and Myanmar.