Agriculture Reference
In-Depth Information
Mesh-bottomed floors
were discussed earlier in the topic. While not effective on their
own, they help to reduce varroa numbers, and mesh floors are better for colonies
anyway.
Varroa mites often fall off the bees onto the floor. They then clamber back onto a passing
bee and recommence their damage. If there is a mesh floor, they will fall out of the hive
and be lost. A floor devised by a Belgian apiarist employs this principle of losing varroa
mites. It consists of a series of long, smooth tubes with gaps between them. The varroa
mites are unable to cling onto the tubes and thus fall out of the hive. This is a simple
and apparently effective method but is very expensive to purchase.
Heat treatment
works but is time consuming and is only 50-80% effective, according
to US research. It is currently popular in Russia. The theory is that adult female mites
are more sensitive to temperatures above normal brood-nest temperature (34° C; 93°
F) than are the bee larvae and pupae themselves. If you heat the bees in a colony up to
44° C, (111° F) for 4 hours, the varroa mites on the brood will therefore die but the
larvae will, in the main, survive. There will still be a great many mites on the adult bees,
though. With its limited kill rate (compared with other methods) and the undoubted
stress it puts on the bees, I would not recommend this method.
Finally,
co-ordination with your neighbours
helps to reduce re-invasion from untreated
stocks and can play a vital part in any varroa treatment programme. Many beekeepers,
however, fail to recognize this. If they did, this would make life a great deal easier -and
cheaper - for everyone.
Biological controls
Breeding programmes
mainly involve the selection of genetic traits that are hostile to the
varroa mite's reproduction cycle or worker-bee traits that actively remove or hinder the
mites. The 'suppression of mite reproduction' (SMR) has been extensively studied in
the USA, and the selection of traits in the honey-bee population that effectively limit
the mite's reproductive ability seems to be bearing fruit. These programmes are not
easily carried out, but all beekeepers should keep up to date with varroa treatments and
methods of control.
