Prevention
Prevention is preferable to cure and there are a number of steps that can be taken to make sure any infestation outbreaks are reduced and contained. One of the main routes for infestation entering the Museum environment is for pests to be present in specimens or material brought into the Museum. Whether in infected loan specimens or in untreated exhibition or functions display material ( i.e. damp logs or display case groundwork). It is important therefore to inspect all specimens and materials entering the Museum which may place specimens at risk, taking appropriate action before exposure occurs.

Hygiene
Pests require a food source to survive and can find it in the form of dirt and domestic dirt. Un-emptied waste bins, dropped food crumbs, un-vacuumed carpets, unwashed towels and protective clothing can all be potential food sources for insects and even rodents. It is important therefore to maintain clean exhibition, work and storage areas, regularly removing rubbish and vacuuming carpets.

Enclosure
Insects can enter buildings by open windows, ventilation grills, etc. Ideally these should have a fine mesh covering to prevent access. Doors should have a close-fitting draught excluder to prevent access around gaps. Showcases should be air tight, the newly hatched young of carpet beetle Anthrenus verbasci are small enough to crawl through the tiniest of gaps. Any specimen or object potentially at risk i.e. with fur, feathers, skin etc. while not on display should be kept in a closed plastic bag also containing insecticide. This should be kept in a cool, dry environment away from direct sunlight, 18/20º C, relative humidity 50 +/- 5 %. This will prevent the specimen becoming infested but also contain the infestation if it is already infested.

Monitoring
An important aspect of pest control is regular inspection of specimens on display. This inspection should look at the condition of specimens and take note of any changes seen. Specimens should be kept clean so new 'dirt' and detritus can be seen easily. The first signs of an infestation may be the appearance of 'frasse' - debris left after the emergence of the laval stage of the varied carpet beetle or wollybear Anthrenus verbasci through the skin of the specimen. If an inspection with a magnifying glass reveals this frasse as droppings, and they appear fresh, light coloured and lemon shaped, then the infestation is recent and action should be taken immediately. Another sign is the shed skin cases found scattered around the feeding area, this could be signs of a previous infestation however as these can remain for up to fifteen years before decomposing. Often the larvae themselves will still be present and can be removed manually before the specimen is treated.

This inspection should take place in May/June as this is when the larvae emerge, pupate and the adults try to fly outside to mate.

The use of insect traps is effective in detecting whether insects are active in showcases and can reveal an infestation before any specimen damage is found. Sticky traps, such as Hoy Hoy traps have been successful in catching adults of varied Carpet beetle (Anthrenus verbasci (linaeus)) Spider beetle Ptinus tectus Boieldieu and Furniture beetle Anobium puncatum. Corrugated cardboard pitfall traps with an attractant oil, i.e. Storguard ™ have also been successful in catching carpet beetle larvae Anthrenus verbasci where a visual inspection did not detect it. Pheromone traps have also been successful in catching Carpet beetle Anthrenus verbasci.

Treatments
If an active infestation is found, action will have to be taken to eradicate pests and prevent further infestation immediately. Temperature control is a good method of eradication, keeping material at a temperature of minus 20 º C for at least 48 hours will kill insects. Freezing all incoming specimens is recommended, providing they will not be damaged. This will help safe guard against inadvertently placing the rest of the collections at risk [see freeze process ]. Also heating material to a temperature above 50 º C, if practical, will eradicate pests. This may be a suitable way to treat incoming showcase groundwork.

Fumigation is effective also, with the use of a Rentokill Bubble a large quantity of material can be treated. Chemical treatments using this method, i.e.. Methyl Bromide, Ethylene Oxide, Paradichlorobenene, though effective, present a problem when it comes to opening the bubble, as these highly toxic gases will be released into the atmosphere.

A better method is to use sufficient inert gases, i.e. Carbon Dioxide or nitrogen at a temperature greater than 25 º C. The insects will suffocate through lack of oxygen. This can take up to 3 weeks to be fully effective but at the end of this period the gases can be released safely into the atmosphere. To comply with Health and Safety regulations, fumigation should only be carried out by qualified professionals. [see anoxia process ] This may also be a suitable way to treat incoming showcase groundwork.

Insecticides
Temperature control and inert gas fumigation will kill the infestation but not prevent reinfestation, to achieve this chemical pesticides will have to be used. To comply with Health and Safety regulations any one using pesticides must be qualified to do so. (The food and Environment Protection Act 1985, Control of Pesticides Regulations 1986)

*The use of Dichlorvos as a vapour, lethal to insects, which builds up inside a showcase is effective. The tablets should be placed high inside the showcase as the vapour is heavier than air and will sink, building up the effective dose over time. It is necessary to follow the instructions on the packet to comply with Health and Safety regulations and not exceed the quantity per space specified. Avoid over exposure to the vapour when handling as this can cause headaches, drowsiness and dryness of throat symptoms. It is advisable to wear gloves, a mask and protective clothing when handling the tablets.*

Other chemical pesticides treatments may be effective. Chemicals such as Permetherin and Cypermetherin found in various pesticide products will be useful in killing most infestations. The advantage of these chemicals is that while being lethal to insects, they are fairly safe for human use. Permetharin has a lethal dose of 2/3000 compared with 1500 for salt and 15 for nicotine. It is a skin irritant however and gloves should always be worn when handling.

Drione is a Permetharin based product. This is in a powder form and is placed where insects will walk into it. The powder is Silica Aerogel which acts like broken glass on the insects legs stripping off the protective wax layer, the insects will then die of dehydration. Tests are being carried out at the NHM in the Invertebrates 1& 2 groups and Entomology of this product.

Cypermetherin is available in a pen dispenser which is used to literally draw a line of exclusion over which insects cross at their peril. Other products available are using these active ingredients.