Responding to a poisoning event

An increase in the number of managed hives available for crop pollination is crucial to the continued prosperity of the Australian horticultural industry. Further development of the managed pollination sector will also provide important opportunities for the honey bee industry. However, a significant barrier in this regard has been the risk that beekeepers face in relation to honey bee pesticide poisoning.

Pesticide poisoning events of managed hives have occurred in Australia, and they have mainly occurred from a chemical toxic to bees being inappropriately applied to flowers in a crop, or from spray drift from neighbouring paddocks.

Although it is important to put in place mechanisms to ensure that these instances do not occur, it is also important to understand how to respond to a honey bee pesticide poisoning event if they do occur. The information contained below summarises some of the symptoms that may be associated with the hives, how to best manage hives in affected areas, as well as information about who to report the matter to for investigation.

A honey bee poisoning event. Notice all the dead bees at the front of the hive. Bryn Jones, Crop Pollination Association

Identifying the symptoms of poisoning

• Significant numbers of dead bees are found outside the hive entrance.
• In severe cases, dead adult bees will be found inside the hives as well and brood will die from starvation, overheating or chilling (due to inability of adult bees to feed brood and regulate hive temperature).
• Adult bees all die within a few days of each other.
• Most or all hives in an apiary may be affected.
• Dead adult bees often have their wings unhooked and at odd angles to their body, their proboscis fully extended, and their hind pair of legs outstretched behind them.
• A lack of foraging bees can be observed leaving the hive.
• Live adults may look sick (eg move slowly, show signs of paralysis, jerky motion).
• Remaining bees may behave aggressively.
• Queen failure may occur within 30 days.

Managing affected hives

• Move hives to a safe area.
• Remove excess supers so that colonies can stay warm.
• Consider removing pollen and honey which may be contaminated, and dispose of appropriately if necessary.
• Feed colonies inside the hive with a 1:1 sugar and water solution until recovery. This helps compensate for the lack of fresh nectar resulting from reduced bee numbers. It may also be necessary to feed either pollen or pollen substitute.
• Add sealed brood and adult bees from healthy hives if needed. Ensure that young bees are added as well, to assist with the feeding of unsealed brood in the weakened hive.
• Observe hives for signs of queen failure or supersedure, which may occur a number of weeks after the poisoning event.

Investigation and reporting

The action that a beekeeper takes will most likely be determined by the severity of the poisoning event and the beekeeper’s relationship with the farmer concerned, or other farmers in the area. Always remember that bees can fly over 5 km, so the poisoning event may not have occurred with the farmer that the beekeeper is working with, it could be a neighbour for instance who does not know that there are bees in the area. Regardless however, it is a good idea to collect samples that can be sent to a laboratory for analysis if required. Proper investigation is important to ensure that farmers, who have done the right thing, are not unfairly blamed. There are three types of samples that can be taken:

• Dead bees from outside the hive.
• Dead bees and comb from inside the hive.
• A swab sample from the outside of the hive.

Providing a swab sample from the outside of the hive is appropriate if you suspect that a chemical has come directly into contact with the hives (eg spray drift or aerial application), whereas the other two sample types should be taken for all poisoning events. The following things should be considered when collecting samples:

• Bees should be picked up with sterile tweezers or gloves, and comb should be cut with a sterile knife.
• A swab can be taken from the outside of the hive using a clean tissue or cotton wool ball.
• All samples should be contained in sterile specimen jars, such as the type commonly used for sending honey samples for laboratory testing. If such a jar is unavailable, a clean, sealable glass or plastic container can be used (eg snap-lock bags).
• If unable to be dispatched immediately on ice, samples should be frozen. This slows the breakdown of both dead bees and chemical residues.
• Samples should be properly labelled (eg ‘bees from outside the hive’ or ’20 cm x 20 cm swab sample from the outside of a hive’). When submitting a swab sample, it is important to advise the laboratory of the size of the area that was swabbed.
• 25–40 bees, or at least 20 g, should be collected per sample.
• For swab samples, area of at least 20 cm x 20 cm should be swabbed.
• For comb samples, a piece of comb at least 10 cm x 10 cm should be sampled.

For a summary of the information to include and what symptoms to record, download the Pesticide poisoning report.  This report is an extract from Honeybee pesticide poisoning: a risk management tool for Australian farmers and beekeepers,  published by the Rural Industries Research and Development Corporation.

Any adverse experiences should be reported either to the relevant state or territory government agency or to the APVMA’s Adverse Experience Reporting Program on 1800 700 588.

References

The information on the pesticides toxic to honey bees is from Daryl Connelly (2012) Honey bee pesticide poisoning – a risk management tool for Australian farmers and beekeepers, Rural Industries Research and Development Corporation Publication 12/043.

Report a honey bee pesticide event