Insects gnaw on organic materials and leave telltale signs of feeding. These could be holes, deep furrows or surface traces. Some insects form gossamer threads, while others leave sprinklings of sawdust-like particles behind.

The following link leads to a table listing what materials are attacked by particular forms of mold.

Mold on various materials

There are many strategies for identifying whether an insect infestation is active or not. First of all, search for living bugs and living predators of the pests in the area around the object in question. Pheromone traps can be set up to find living pests during their flying stage. Also examine the surface of the object closely. Small entrance holes with a light edge and a sprinkling of sawdust around it indicate an active infestation. One good and simple method is to tape over the old holes, then it is easy to see what ones are new. Pest in objects can be detected by means of layered X-rays. See also the overview at the following link.

Detecting an active insect infestation

It is only possible to use a microscope to identify the exact type of mold in the case of very characteristic types of mold. It is generally not possible to distinguish between living and dead cells, except with the aid of fluorescent dyes and color indicators in some cases. By taking samples with the aid of adhesive strips and tapes and cultivating the mold, it is possible to detect living cells that are capable of germinating and determine the density of the infestation. See the link for more details.

Methods for detecting mold in collections

The table (see link) lists the most important pests found in museums along with the type of materials they tend to attack in each case ? wood, plastic, paper, textiles and plant-based substances.

Materials and the type of insects that attack them

Chemically speaking, plastics are composed of organic materials. It is well known that natural organic materials such as wood can be broken down. What is less well known, however, is that plastics can also be attacked by organisms.

Bioresistance of plastics

Insects and mold spores are carried into exhibition galleries, storage rooms and workshops with outdoor air, on the clothing of staff and visitors, and on new acquisitions. Food, flowers and indoor plants are further potential sources of infection. Particularly critical areas are any restaurants and cafes in the building if there is no strict separation between them and collection rooms. Even with brand new interiors, it is not possible to be 100 % sure they are free of pests.

Structural defects, especially moisture in walls and roofs, as well as operating mistakes, such as incorrect ventilation, facilitate the spread of mold. One mistake that is frequently made is to place furnishings too close to an exterior wall without ensuring adequate ventilation in the space between. With wall coverings, textile hangings without ventilation behind, and tightly closed curtains in front of windows, in winter there is a risk of condensation forming which could lead to mold growth.

Structural measures can greatly reduce the number of harmful insects infiltrating a building. Windowless rooms with only one door are advantageous. Objects that are particularly at risk should be placed in insect-proof showcases and collection cabinets, or in sealed film bags. It is advisable to vacuum collection cabinets and wipe them with a damp cloth once a year in order to remove everything that could serve as nutrition for pests. In storage rooms with books and archival materials affected by mold it is advisable to avoid using conventional vacuum cleaners as the spores could be sucked through the filters and blown out into the room. Humidifiers and dehumidifiers should be cleaned at specified intervals so that no mold and bacteria can colonize them. Because they are only effective for a limited time, pheromone traps are relatively labor-intensive and costly as a preventive measure. Moreover, they can attract insects from outside the building as well. Fabrics or porous materials (e.g. wood) soaked in essential oils such as clove, lavender, cedarwood, patchouli or thuja oils can be placed next to artifacts to deter insects.

There are various ways of treating insect infestations. From an ecological point of view, physical methods such as heat and cold treatment, microwaves and gamma radiation or low-oxygen environment (nitrogen chamber) are better than liquid chemical treatments, the residues of which often cause unwanted changes. These methods offer no preventive protection, however. Chemical preparations should only be used if all other treatment options have been ruled out. Also make sure that any pest treatment chemicals contain natural insecticides that biodegrade as rapidly as possible.

Routine checks should be carried out once a year and should include picking the object up and examining it from all sides.

Annual cleaning is necessary, as dirt deposits can serve as nutrition for insects and mold.

Lower forms of fungi (commonly known as mold) are microorganisms which form filaments (mycelium) on materials, as well as small fruiting bodies and spores which can only be detected under a microscope. The filaments can be readily seen with a magnifying glass. See the link for further information about detection methods.

Detecting mold in the air

As part of the regular cleaning regimen, rooms should be inspected for insect residues and bugs twice a year.

Pests are often introduced on new acquisitions and loans, from where they can spread to other items in the collection. They should therefore be quarantined in a separate room for around four weeks.

Mapping records whether insect feeding traces or mold mycelium are evident on new acquisitions.

If pests such as insects and mold are present in the materials used for constructing an exhibition, they can go on to attack the collection.

Having at least two sets of doors between the exhibition/user area and the entrance disrupts the infiltration routes of pests.

The cloakroom area and exhibition spaces should be separated by at least one door to prevent pests being brought in.

Maintaining a constant indoor climate means maintaining a temperature appropriate to the season which does not fluctuate too widely plus ensuring that humidity remains below 60 %. This prevents the moisture content of materials rising above 20 %. Mold spores can only germinate when the moisture content is above 20 %.

Specific emergency measures are quarantine and treatment.

Specific emergency measures include quarantine, treatment, and investigating the causes.