Most of the wood preservatives contain pesticide, fungicide, insecticide or chemicals. Some contain highly harmful chemical to human, plants and bees; the others are less harmful. The original Creosote was very effective for fence or shed and once it has been used, it will preserve wood for approximately over 20 to 40 years. Creosote is no longer safer due to its Carcinogenic properties and it is still available to trade people – presumably because they will wear breathing apparatus when applying it. Creosote Alternative or Creocote looks like Creosote, smell like Creosote, but it contains a chemical Dichlofluanid.
Wood preservative with the active ingredient Dichlofluanid (a sulfamid fungicide) has created a disaster in Denmark . It was marketed in Denmark under the retail product name ‘Rentolin' and without a warning against indoor uses. Some wood preservatives containing dichlofluanid are marketed as ‘Preventol' and ‘Flourofolpet'. People, who used Rentolin indoors, suffered serious injury. Many houses are now inhabitable, and several people suffer from chronic diseases. Some have the diagnosis of MCS (Multiple Chemical Sensibility). Dichlofluanid is on the EU list of hazardous substances, classified as an allergen and hazardous to the environment (issue 17, chemical preservatives 2001).
Cuprinol Decorative Wood Preservers including Red Cedar shade may be used to externally on empty beehive providing hives are opened up and allowed to dry thoroughly for a period of minimum six weeks. No beekeeper should use wood preserver on outside the hive whilst bees are in the hive. Both preservers contain main ingredient Dichlofluanid. I am surprise Curinol did not warn beekeepers that Dichlofluanid is harmful to bees, but Cuprinol insists to dry the wood preserver thoroughly (min 6 weeks) before introducing to bees. Preservers have advantage over the paint in that it allow the wood to breathe and water vapour to escape and easily maintained
Cuprinol Low odour Wood Preserver Light Oak and Dar Oak contain Acypetacs-Zinc, which has been recommended for treating beehive in the past, is no longer easily obtainable. However Cuprinol Wood Preserver – Clear contains Acypetacs-Zinc and Cuprinol Wood Preserver – Green contains Acetypetacs – Copper have a low toxicity to bees, are recommended for preserving hive externally only, both are available in the UK. The Acetypetacs Zinc formulation is said to be safer than the Acetypetacs Copper
Howerver Ronseal say that their “Quick Drying Woodstain” is OK for bees. Do not confuse with Ronseal's other stains for Garden Furniture Decking etc. Preservative should be used only on the outside of the hive and be well aired before use. There is significant evidence that residues from materials have been found in bees, brood and wax, if preserver is used inside the wall of the hive or where bees do have contacts.
Most of the beehives are made of hardwood, either cedar or some other softwood such as pine or fir sometime referred to as deal. Cedar is naturally a durable wood, which does not readily absorb moisture, so does not require preserving or painting to prolong its life. It is therefore a good investment.Woods vary in durability, and, despite the name, hardwoods are not necessarily more resistant to rot than soft woods. Oak, sweet chestnut, western red cedar, should last around 20 years in contact with water and ground, with no treatment; pine will last around 5 years, larch about 10 years.
Economy beehives are made of pine or other softwood, which is susceptible to the weather and requires some preservative to prevent rot, shrinkage & warping, especially in the joints. Ventilation is vital in the hive to prevent condensation Open mesh floors provide adequate ventilation throughout the year and walls have to be water vapour permeable.Wood preservatives include insecticide, fungicide and pesticide therefore bees can be put at risk if it is used. Only use externally and allow to thoroughly dry out before using on the colony.
Most commonly the ingredient used in the wood preservative is Chromated copper arsenate (CCA). CCA is good for preserving wood and also is a termite preservative, but does harm bees. It is suggested that beekeepers should be careful about treating beehives with CCA.The materials should be avoided if possible, when treating beehive are pentachlorophenol (PCP), (sometime it is called penta), tributyl tin oxide (TBTO) and CCA. The preferable are the proven preservatives; copper naphthenate, acid copper chromate (ACC) and copper-8-quinolinolate.
These preservatives extend hive life from an expected ten to a potential twenty years; however, their effectiveness against termites is open to question. According to tests by the US Environmental Protection Agency (EPA), the main active ingredient of copper naphthenate is safe for preserving wooden parts of the beehive. In fact EPA do not recommend using preservatives containing arsenic, creosote and pentachlorophenol on beehive.
According to the University of Wisconsin-Extension publication A3086, Protecting Honey Bees in Wisconsin from Pesticides and Other Toxic Chemicals , the following must be taken into account when considering use of materials on beekeeping equipment. Highly toxic chemicals where severe losses may be expected if materials are used when bees are present at treatment or within a day thereafter include the wood preservatives: Arsenic containing compounds: creosote, flou-chrome arsenate, copper chrome arsenate, pentachlorophenol, zinc-copper-chrome arsenate and tributlytin oxide.
Relatively non-toxic chemicals, which can be used around bees with a minimum of injury, include the wood preservatives: acid copper chromate, copper naphthenate and copper 8 quinolate. Experiments show that hive treated with creosote, pentachlorophenol ( PCP ), tributyl tin oxide (TBTO) and chromated copper arsenate (CCA) were associated with adverse effect on bees and left residues of preservative chemicals in bees, wax and honey. All were also associated with poor winter survival of colonies. In particular, PCP Tranlocated from treated hive to honey, bees and wax. Greatest concentration of PCP was in bee wax. Bee wax has a number of uses like cosmetics for which is essential.
Mr. M.T. Sandford of University of Florida writes according to a paper by M. A Kalnins and Bejamin Detroy that CCA treated resulted in elevated arsenic and chromium levels in bees, arsenic in some cases in the lethal range. Chromium levels although elevated were below 1 part per million (ppm) in both bees and honey. TBTO treat resulted in tin levels of several ppm in bees and wax. The authors suggest, that beekeepers not to use PCP, TBTO or CCA for beehive treatment. CCA could be used only on hive parts not in contact with bees. Any materials with arsenic component are potentially very damaging to bees. CCA or pentacholorphenol would be acceptable for beehive, if applied only on the outside so that no residue should contaminate honey, wax or bees.
CCA treated timber, often called ‘tanalised' or ‘pressure' timber. This treatment uses chemical such as copper arsenate, which are very poisonous to human – so the treatment should be carried out in carefully controlled conditions. Research carried out in the USA suggest that arsenic may leach from CCA treated wood into the soil, and traces of arsenic have been found on the hands of children who have been playing on equipment made from such timber. This may be possible that wood has not been adequately dried after treatment. Gloves should be worn when handling this kind of timber, and care should be taken not to inhale the dust when sawing or working it in any way. It should not be burned.
Reprint from The Scottish Beekeepers. Author. Arshad Farooqui