Biosecurity Problems for North Australia - New Issues

Two biosecurity issues have emerged recently in the Darwin area, both with potentially catastrophic outcomes for Australian agriculture if not solved.

A few weeks ago citrus canker was detected in a nursery near Darwin, and subsequently found on six properties in the near Darwin area.  Today it has been announced now also found in the Kununurra /Wyndham area of WA with the source apparently from an NT nursery.

This is potentially a  major issue for the Australian citrus industry.  Early days, but eradicating it will be a big task.  Yet, in Florida where outbreaks occur with some monotony, it is also regularly eradicated from large orchards but using a cut and burn approach.  Serious stuff requiring a serious approach.

The other is a detection of Asian honey bees in Karama, a Darwin suburb.  The swarm has been eliminated, but they are seeking any nests and these require checking for varroa mite, the main problem.  This is some distance from the Darwin port, and with ports seen as a likely point of entry, the distance away from the port is perplexing.  Will be more to come on this one too.

If detected there are larger implications for the whole Australian honey and queen bee industry [ yes, Australia exports queen bees!].

Both early days, and there is more on this web site, and the ABC Rural has had stories on both subjects recently.

See - https://dpir.nt.gov.au/citrus-canker 

A word of advice - check your citrus tree or trees for citrus canker!! 



UPDATE - 7 June 2018

More citrus canker has been discovered.........with a number of trees including one with a severe infestation, discovered in the Katherine area.

Not a good find!

Check any citrus trees on your property, and do not move fruit or vegetative materials of citrus.  Check the link above for the current current situation.

This is a very serious issue, for local citrus producers as well as the huge citrus industry interstate. 

Varroa Mites Might Get the Flick

One of the scourges of modern apiary production in many countries has been varroa mites. While not in Australia, they are very problematical in the US.

They have been also, at least it seems, partially implicated in Colony Collapse Disorder, which has wrecked many US apiarists and the availability of bees for pollination duty in horticultural production. This has been a plus for Australia, as new queen bees have been sold to the US. CCD is a complex issue, and there have been stories published that even these overseas queens are implicated in the disorder.

But on the varroa mite front some excellent news has recently been published from the US ARS.

Their media release is below

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Honey bees are now fighting back aggressively against Varroa mites, thanks to Agricultural Research Service (ARS) efforts to develop bees with a genetic trait that allows them to more easily find the mites and toss them out of the broodnest.

The parasitic Varroa mite attacks the honey bee, Apis mellifera L., by feeding on its hemolymph, which is the combination of blood and fluid inside a bee. Colonies can be weakened or killed, depending on the severity of the infestation. Most colonies eventually die from varroa infestation if left untreated.

Varroa-sensitive hygiene (VSH) is a genetic trait of the honey bee that allows it to remove mite-infested pupae from the capped brood–developing bees that are sealed inside cells of the comb with a protective layer of wax. The mites are sometimes difficult for the bees to locate, since they attack the bee brood while these developing bees are inside the capped cells.

ARS scientists at the agency’s Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge, La., have developed honey bees with high expression of the VSH trait. Honey bees are naturally hygienic, and they often remove diseased brood from their nests. VSH is a specific form of nest cleaning focused on removing varroa-infested pupae. The VSH honey bees are quite aggressive in their pursuit of the mites. The bees gang up, chew and cut through the cap, lift out the infected brood and their mites, and discard them from the broodnest.

See this activity in the attached video link here:
http://www.ars.usda.gov/is/br/bees/index.htm

This hygiene kills the frail mite offspring, which greatly reduces the lifetime reproductive output of the mother mite. The mother mite may survive the ordeal and try to reproduce in brood again, only to undergo similar treatment by the bees.

To test the varroa resistance of VSH bees, the Baton Rouge team conducted field trials using 40 colonies with varying levels of VSH. Mite population growth was significantly lower in VSH and hybrid colonies than in bee colonies without VSH. Hybrid colonies had half the VSH genes normally found in pure VSH bees, but they still retained significant varroa resistance. Simpler ways for bee breeders to measure VSH behavior in colonies were also developed in this study.

This research was published in the Journal of Apicultural Research and Bee World.
ARS is the U.S. Department of Agriculture’s chief intramural scientific research agency.