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Margaret Murdin, NDB, BBKA President

April usually heralds the beginning of the beekeeping year proper, when we can inspect our hives in earnest. But remember that dates are not important to bees, it is the weather and availability of forage that count. Clearly, we all hope for fine weather, but we must carry out a full inspection of a colony only if the temperature is above 16 ºC.

What we can’t assume, though, is that, just because our bees have survived the winter, they are healthy. They may not be, and this is the time to check.

Beware EFB

Often, at this time of year, the brood nest will be large compared to the size of the colony (remember the graph from my February article, page 18). The young larvae will be fed only just enough, so the colony is more likely to show signs of European foul brood (EFB) if it is present. This is a bacterial disease where the bacteria compete with the larvae for food. If there is a shortage of food the bacteria win. If there is EFB in the hive, it should become obvious at this time.

The shortage of adults in the colony also means that they have little time for jobs like undertaking, so dead and diseased larvae are more likely to be left in the cells to be found by the observant beekeeper.

Disease Inspections

As long as the weather is fine, we can carry out a full disease inspection this month, checking very thoroughly for both adult and brood diseases.

But remember, we need to work quickly and efficiently and Ap ril usually heralds the beginning of the beekeeping year proper, when we can inspect our hives in earnest. But remember that dates are not important to bees, it is the weather and availability of forage that count. Clearly, we all hope for fine weather, but we must carry out a full inspection of a colony only if the temperature is above 16 ºC. What we can’t assume, though, is that, just because our bees have survived the winter, they are healthy. They may not be, and this is the time to check. Beware EFB Often, at this time of year, the brood nest will be large compared to the size of the colony (remember the graph from my February article, page 18). The young larvae will be fed only just enough, so the colony is more likely to show signs of European foul brood (EFB) if it is present. This is a bacterial disease where the bacteria compete with the larvae for food. If there is a shortage of food the bacteria win. If there is EFB in the hive, it should become obvious at this time. not become distracted looking for the queen.

We need to smoke the colony with cool smoke to calm the bees then remove the roof, super (if there is one) and the crownboard. Any insulation in place for the winter should also be removed now.

If there is a dummy board it can be removed along with any old frames that are being replaced.

For this disease inspection we are interested in observing four aspects of the colony: the adult bees, the brood, the brood frames, and any frames which have contained brood but are now empty or carrying stores.

Careful Examination

Take each frame containing bees, hold it over the brood nest and check the adults on both sides. Do they look well formed? Are there any with stunted abdomens? Look carefully for stunted or shrivelled wings as these are likely to be caused by deformed wing virus which is associated with varroa. Can you see any varroa mites? Most mites will be quietly reproducing – unseen – inside sealed brood cells so few are likely to be on the adult bees.

Now move the remaining frames apart so that there is a reasonable space in the centre of the hive. Hold the frame vertically and, lowering it half way into the space you have just created, carefully shake off all the bees. Inspect each brood cell. Start from the outside and work inwards in concentric circles.

Check the Brood

Make sure you know what healthy unsealed and sealed brood looks like. Sealed brood should be biscuit coloured, slightly domed, dry, and in a regular pattern. Look for any abnormality. Are there any pierced, broken or damaged cappings? A small hole in the centre of a capping is usually normal and will be the first signs of a young adult emerging. But holes at the edges are not normal. Nor are greasy or sunken cappings.

Are there lots of cells that are empty, where the queen has not laid? If so, this could be a ‘pepper pot brood’ which can have several causes.

Uncapped larvae should be creamy white and lying curled in a ‘c’ shape in their cell. Are larvae lying in awkward positions? Have they lost their segmentation or do they look shiny? Can you see the gut through the larval wall and, if so, is it an odd colour?

Look also for signs of chalkbrood or sacbrood, pictures of which can be found on the BeeBase website (www. nationalbeeunit.com). These are minor diseases usually, but each chalkbrood mummy or sacbrood slipper means the loss of a worker bee. And the colony has expended valuable resources creating the larvae, so there is a double loss.

Look for Scales

Now, hold each frame which has had brood in it at an angle of about 45º in front of you, with the light coming over your shoulder. If it is a dull day you might want to use a small torch. You need the light to shine on the bottom corner of the cell. That part of the cell nearest to the bottom bar is what you need to be looking at, not the bottom near the midrib. You are looking for a shiny scale which is dark brown or black. The scale is the remains of larvae which have died in their cell and is usually an indication of either European foul brood or American foul brood (AFB), both of which are notifiable diseases and must be reported to your bee inspector or the National Bee Unit.

Continue working systematically through the frames making sure you shake all the bees into the brood box and continue to control the colony with smoke.

Next, check the varroa insert under the open-mesh floor (if you use one) and calculate the daily mite drop using the instructions and calculator on BeeBase.

Replace any old combs that you have removed with sterilised drawn comb if you have it or, if not, with foundation.

Finally, take a sample of 30 adult bees from the front of the hive or the outside frames. They need to be checked for acarine and nosema so they must be older because the disease will not have had time to develop in younger nurse bees. If you are unsure what to do with them, ask an experienced beekeeper or a microscopist, if you have one in your association.

If anything about what you find in your colony is a cause for concern, ask a more experienced beekeeper to come and have a look, or contact your seasonal bee inspector for advice.

Finally, check the stores. There are many young larvae to feed at his time of year and the weather is fickle. So make sure they have enough pollen and honey or sugar syrup to last until your next visit.


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