Bee Pests and Parasites - Amazing Bees | Beekeeper Section

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Bee Pests and Parasites
What might come as a surprise to new hobby beekeepers is the realisation that bees are being threatened by diseases, pests and parasites.

Virtually every beehive in the field is providing shelter to a number of large and small creatures.

Bees are being threatened by pests and parasites.

Most of these uninvited visitors don't pose a serious threat to the bees.

However, some can destroy the entire bee colony and cause damage to the beehive.

Regular monitoring of colony strength, pests and diseases is a vital element of successful beekeeping.

Uninvited visitors
It needs to be pointed out that a strong and healthy colony of bees does not tolerate any visitors in their hive!

Therefore, these uninvited visitors can only be found in hives where the bee population has declined in numbers, leaving a large unoccupied space in the hive; this can happen during winter when the shrinking bee colony retreats to a small area in the hive, leaving the rest of the hive unattended.

It is therefore very important before winter to compact the bee colony into one box, two at the most, hereby ruling out the possibility that parts of the hive remain unattended during lengthy periods of cool temperatures.

Beehives can provide shelter to a number of large and small creatures such as spiders, earwigs, cockroaches, slugs and snails. These uninvited visitors don't pose a serious threat to the bees, nevertheless they are at least a nuisance and certainly don't present a very appetising image of a beehive.

Slugs and Snails
After periods of cool and wet weather conditions don't be surprised to find slugs and snails in your hive, not a very appetising image. Apparently bees don't want to touch these slimy creatures; who would? This applies in particular when hives are located in grass areas. When weather conditions are getting warmer and dryer these visitors disappear, but snails who crawled into the hive when they were little, have grown and cannot escape through the entrance; the result: dried out snail shells in the hive. When opening the hive for the first couple of times in spring, inspect the hive thoroughly and remove snails and slugs and all other debris.

Slaters or Woodlice
Woodlice are not generally regarded as a serious household pest as they do not spread disease and do not damage wood or structures. Woodlice need moisture and so are usually found in damp, dark places, such as under rocks and logs, and in beehives in winter or during cool and wet conditions. They are purely of nuisance value, as they do not bite, sting, or known to transmit diseases, nor do they infest food, clothing or wood and they don't present a very appetising image in a beehive. Woodlice can be found inside the hive in close proximity to slugs; apparently they clean up the debris of slugs and snails.
Wood louse

Spiders inside the hive
When you open your hive don't be surprised when occasionally you find a spider inside. We have seen Woodlouse Spiders Dysdera crocata; their specialty is to feed exclusively on woodlice. The venom of the woodlouse spider is not dangerous to humans. However, their bites are really painful and the venom may cause an allergic reaction in some people.


Spiders outside the hive
Less of a surprise should be to find spiders outside of your hive. Where possible they build their web directly on or underneath the hive or nearby. With their web they catch insects and where would they find more insects than close to a hive? Numerous times we have had Redback spiders under the hive's floorboard, and on one occasion under the lid inside the hive. Redback spiders are found throughout Australia, in drier habitats and built-up areas. They are common in dry places around buildings, outdoor furniture, machinery and stacked materials. In the bush, redback spiders nest under logs and rocks.

Redback spiders are not aggressive, and rarely leave the web. However caution is advised as their bite is very poisonous and potentially fatal for children or the elderly. So, if you are not wearing gloves when opening a hive because of your gentle bees, you might want to wear them because of the hidden spiders.


Earwigs
Earwigs are not really considered pest, and in some circles are thought of as beneficial as they feed on other insects, however they are known to eat and damage the soft tissue of developing plants, as well as ripe fruit and garbage and they don't present a very appetising image in a beehive. There are over 60 species of earwigs in Australia. They have short leathery wings, although weak flyers and the abdomen extends well past the wings. Most earwigs are dark brown in colour and around 12–14mm in length. There is no evidence that they harmful to humans or animals despite also being known as “pincer bugs”. Earwigs prefer to live in moist cool situations, although they are somewhat adventurous and will wander.


Cockroaches
Most people think of cockroaches as disgusting little creatures that invade homes and search through food and garbage, spreading germs. There are approximately 450 species of cockroaches in Australia, of which only a handful are introduced pests that have been responsible for this reputation. Virtually all Australian cockroaches found outside of domestic premises are native species and avoid human contact, preferring instead to forage among the vegetation, leaf litter and soil of undisturbed habitats. web link to source
Photos by CSIRO
Native Bush Cockroach
Native Bush Cockroach
Native Flat Cockroach
Native Flat Cockroach

Mice
It never crossed our mind that mice could take up residence in a beehive. This changed when a mouse dashed out of the entrance after opening one of our hives in early spring. This mouse had built its nest on one side of the hive in the frame centre in between three frames, cutting out a piece of comb and weaving hay around the stainless steel wires. The weakened colony of bees used the other half of the hive with no sign of major conflict. Although the entrance had been reduced in size for winter, that did not deter that little mouse, it simply used its sharp teeth to make the entrance big enough. So, don't be surprised.


Frogs
Just when we thought we have seen it all, we got a surprise when we found a frog on top of the hive mat in one of our beehives; it was already dried up.  see photo

It obviously found the way into the hive and up onto the hive mat, but did not dare to climb down again to escape from the bees.
Frog dried up

Snakes
Yes, also snakes find their comfort underneath a beehive!
In spring, September 2011, we relocated some beehives and when we were not expecting it, two lovely little brown snakes (apparently) felt a bit disturbed underneath one of the hives we lifted up. The 25-30 cm long creatures were moving around in a circle first before gently sliding into the grass, away from us, quietly and somehow elegantly. This was our first close encounter with snakes; a mixture of surprise and fright, but also fascination and happiness to have witnessed another lovely creation of nature. Or was it happiness that nothing bad happened?
Even if we'd have had a camera with us we probably would not have had the nerve to take a photo.  Google images of Eastern Brown Snakes


Wax Moths
Wax moths, more precisely the wax moth larvae or waxworms, can destroy an entire bee colony and cause severe damage to the wooden beehive material.

Moths are nocturnal animals and some species are specialised to raise their young on comb used by bees. There are at least two different species of wax moths of different size, from tiny to fairly large - and their larvae are of different size and colour as well.

During the night, when the bees are inside their hive, female wax moths lay their eggs in the hive's cracks and gaps between the hive components, or enter the hive to lay their eggs inside - they are obviously more successful when entering a hive of a weak colony of bees. The wax moths larvae hatch a few days later and make the inside of the hive their home, hiding in little gaps and grooves and feasting on the comb cell's silk lining, produced by the bee pupae, as well as on the comb and its content, honey and pollen. The larvae are able to bore holes and channel their way through timber, mostly wooden comb frames.

A popular hiding place for the wax moths larvae is the groove in the top bar of the frames - but any other little gap inaccessible to bees serves as hiding place during their existence as larvae and pupae. Once the wax moth has transformed into the actual moth it leaves the hive and the life cycle starts again.

A strong and healthy bee colony keeps the wax moths larva population inside the hive under control. It is only when the colony weakens that the number of wax moths larvae can get out of control. Wax moths larvae destroy the comb they are feasting on and spin a web of strong silk around their tracks, hard to be penetrated and cleaned up by the bees. Frame after frame gets spun into wax moths silk and the bees don't find enough cells to raise their brood and store honey and pollen - it's a downwards spiral for the bee population.
Big Waxmoth
Big_wax_moth
Waxworms
Waxworms

A comprehensive reference is this publication by the Agriculture Victoria: AG1101 - Wax Moth - A Pest of Combs and Honey Bee Products

Wondering what the benefits of wax moths are?
Every coin has two sides - find more information about the benefits of waxworms in Wikipedia


Effective preventive measures:
Before re-using beehives/boxes and frames we always keep them in the chest freezer at -30°C for 24 hours to kill off any wax moths larvae and eggs - so far we have not yet had a wax moths problem getting out of control.


Moths Trap - to draw moths away from Bee Hives
An effective method to keep wax moths away from your hives is to use a moths trap.
  • take a 2 litre plastic pop bottle and drill a 25mm hole just below the slope on the neck
  • add 1 cup water, 1 cup sugar, 1/2 a cup of vinegar and 1 banana peel
  • wait a few days till it starts to ferment, then tie it into a tree close to the hives.

This trap will attract wax moths; they enter the hole and can't get out and drown in the liquid.



Small Hive Beetle (SHB)

The Small Hive Beetle Aethina tumida, more precisely the hive beetle larvae, can destroy an entire bee colony and cause severe damage to the beehive, including the honey.

The Small hive beetle is native to Africa and it has recently been spreading to other continents. The pest was confirmed in beehives in the Sydney region in 2002. The larvae contribute to hive death and damage stored hive materials, though damage seen locally has been minimal. They feed on live brood and honey and their excrement contaminates the honey, causing fermentation.


For useful information about the Small Hive Beetle, please follow these links:

Small Hive Beetle - by BeeAware, an excellent source of information

South African Small Hive Beetle - by Aussie Bee, with information about the impact on native Australian bees.

Small Hive Beetle - by the Queensland department of Agriculture and Fisheries

AG1080 Small Hive Beetle - A beekeeping Pest - by the Agriculture Victoria



The three stages of SHB infestation

Stage 1 - Detection of SHB
Most beekeepers in the Melbourne area will have by now noticed a few SHB's in their hives, trying to hide when opening the lid, shying away from the light. Their presence in the hive is not permanent, one time you open the hive the beetles are there, the next time you cannot find any, no matter how hard you try. They seem to visit a hive, then leave and visit another hive. Sometimes you see one or two beetles in the hive, the next time you come across twenty or more.

The photo below shows SHB among bees on honeycomb.
Small Hive Beetle on comb
We have been noticing SHB in our hives since 2013, just the beetles dashing around inside the hive, not laying eggs and not causing any damage.


Stage 2 - our first three cases
Once the Hive Beetles have found a hive suitable for breeding they lay eggs. Important to notice is that they sometimes lay their eggs on the timber floor or the side walls of the broodbox, at least in the first three cases we have experienced over the past years. After hatching from the eggs the larvae seem not to be in a hurry to move away from the timber floor or side walls onto the brood or honey combs.

Provided the larvae get noticed by the beekeeper during regular hive maintenance, this provides a window of opportunity to get rid of the larvae by transferring the bees on their frames into a clean hive box and putting the bee-empty infested hive box in the chest freezer. This worked for us in all three cases we have discovered SHB eggs or larvae.

The photo below shows a brood box infested with SHB eggs and larvae in the front corner of the hive as discovered during regular hive inspection.
SHB eggs and larvae
During 2014 and 2015 we discovered SHB eggs and larvae on the inside of the broodbox and on the bottom board on three occasions but could prevent further damage.


Stage 2 - a close encounter
On 26th February 2016, during regular hive maintenance, I discovered about 30 SHB dashing around inside the hive after opening the lid, never seen so many in one hive, and this was one of our strongest hives (three boxes tall). I was able to squash most of the beetles. Upon inspection of all frames I then made the discovery of SHB eggs on most of the brood combs and some honey combs as well, none on the inside of the hive walls though. There were several clusters of probably 20 eggs and also single eggs deposited on the edge of some comb cells. I could not detect any SHB larvae as yet, so the laying must have just commenced. To prevent this disaster from progressing I decided to shook swarm the whole bee colony into a spare hive box with stickies and foundation frames; all 24 infested frames went through the chest freezer for 24 hours to kill off all SHB eggs. When replacing the old infested hive by the spare hive I discovered another 20 SHB underneath the hive and managed to squash most of them as well.

Provided the SHB eggs get noticed by the beekeeper during regular hive maintenance, creating a shook swarm of the bees into a clean hive box onto stickies, dry comb or foundation only, provides a window of opportunity to prevent further damage. By freezing the infested brood frames you kill all brood; the alternative would be to have them destroyed by the SHB worms.

The photo below shows a brood comb infested with SHB eggs on the edge of comb cells as discovered during regular hive inspection.
SHB eggs on comb cells


Stage 3 - The destruction
The destructive stage of SHB infestation is when the larvae destroy the comb in the hive, leaving a slimy mess behind.
The number of beekeepers who have experienced the devestating effect of SHB larvae is increasing >>watch this clip on YouTube>>

On 1st February 2016 came the big shock for us with the discovery of a Nuc colony infested by hundreds of SHB larvae all over the combs, whaling through the slimy mess they have created. The previous hive inspection two weeks earlier did not indicate something of concern, and now the complete destruction of the colony. Only a handful of bees where in the hive, more precisely in front of the hive on the landing board. It seems they could not stand the smell of vinegar inside the hive and preferred to camp outside. No sign of a queen either, the colony might have evacuated the doomed hive and swarmed out. We closed the entrance and put the whole Nuc box in the chest freezer to end their misery and destroy all SHB larvae.

Brood frame infested with SHB larvae

After more than 24 hours in the freezer we cut out all comb remains from the brand new frames and cleaned up the mess on the hive floor, most of it while it was still frozen. When it warmed up the unpleasant smell of vinegar from the fermenting honey was noticeable.

On 7th February 2016 I was called out to rescue a colony of bees from a possum box that had fallen down from a tree three or four days earlier. When I opened the box it revealed a sticky mess of smashed brood and honey combs and literally thousands of SHB larvae enjoying the feast. That explained why a huge number of bees were gathering outside, instead of being inside the box. Creating a shook swarm of the bees onto dry combs in a clean hive saved this colony. The sticky mess was collected in a strong plastic bag and put in the chest freezer to kill all SHB worms instead of breeding them.


SHB Video Clips by the DPI of NSW
The Department of Primary Industries of New South Wales has published a very useful series of Video Clips on their website and on YouTube to assist beekeepers with the identification of the Small Hive Beetle and its eradication.

Above: Video 8 - Small Hive Beetle
A basic understanding of the biology of a pest is necessary to better equip beekeepers with how and when to consider various strategies to control and suppress this particularly bee hive pest.


Above: Video 9 - Small Hive Beetle Control Devices
A range of devices is available, reported to be useful in controlling small hive beetles. This segment discusses some of these options and how to use them.


Various products are available to counter attack SHB

Most Apiary Supply vendors stock Hive Beetle traps.

BeetlTra - a Small Hive Beetle Trap.

A "bee safe" insecticide, called Apithor - please visit their website for information about the SHB and the product.

Several "new designs" of screened or slotted bottom boards have come onto the market, promising to fight SHB.

To our knowledge none of these products are offering a "silver bullet" for the SHB problem; it is like hanging up a zapper to kill mosquitos, it kills some but not all.


Varroa Mite
The Varroa Mite, coexisting with the Asian honeybee, was introduced from Asia in the 1970's by bee traders and has since then been one of the biggest threat to European honeybees worldwide.

Whilst the Asian honeybee is resistant to the Varroa mite, the European honeybee is getting severely damaged by it.

To date Australia is the only country in the world free of the varroa destructor mite, the mite that destroys European Honeybee colonies.

In July 2016 varroa jacobsoni mites have been detected in an Asian Honeybee nest discovered in Townsville and it is likely to be only a matter of time that varroa destructor finds its way to Australian shores.

Information by Agriculture Victoria is available: AG1183 - Varroa an exotic parasite mite of honey bees


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