The US state of Hawaii is using selective breeding to win the war against the destructive varroa mite, which is crippling honey bee populations around the world.

The overall significance of honeybees is often overlooked, but keeping up natural bee populations is critical for farmers who need crops to be pollinated.

Australia is still free of varroa destructor, but the major pest has been spreading around the world, including to neighbouring New Zealand and Indonesia.

Dr Danielle Downey, from the Hawaii Department of Agriculture, is trying to rid the Hawaiian islands of the pest, by breeding disease-resistant bees.

She has had some success, which could help Australia prepare for what many see as the inevitable spread of varroa mites here.

Varroa mites on honey bee pupae. ( Queensland Department of Agriculture, Fisheries and Forestry )

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 minutes 51 seconds 5 m Danielle Downey from the Hawaii Department of Agriculture is trying to rid the Hawaiian islands of the pest, by breeding disease-resistant bees. ( Marty McCarthy ) Download 2.7 MB

"We started with a mishmash of bees with a variety of vulnerabilities to varroa mite," Dr Downey said.

"What we're hoping to come up with is a bee that is well-suited to Hawaiian conditions and is able to help itself against varroa mite.

"We want the bee to keep the levels of varroa low without us having to treat it with pesticides."

Dr Downey said that, in the colonies she had surveyed which contained the varroa-resistant bees, she had recorded a varroa mite prevalence of less than five per cent.

"We have colonies that have gone now for almost a year with less than five per cent varroa mites, which is pretty low in a place with year-round breed production," she said.

Varroa mites have reached Australia in the past, but were immediately destroyed upon detection. The Department of Agriculture estimates that if the pest does establish itself in Australia it will cost the agricultural industry $70 million a year.

Hawaii is similar to Australia in that its isolation in the centre of the Pacific Ocean usually protects it from agricultural pests and diseases that spread easily around the world. Although varroa mites did reach its shores, only some of the islands that make up Hawaii are infected.

"Hawaii has a chain of islands and two of them have varroa mites, the Island of Oahu, where Honolulu is, and the big island, Hawaii," Dr Downey said.

"We're stuck with the varroa mite on the islands where it already exists but we can try to find a bee that does the best resisting of varroa mite damage."

Dr Downey said the breeding project involved identifying bees that know when they have been infected with varroa mite, and then using select breeding to adapt these bees to local conditions.

"There are bees that have been selected that can detect the varroa mite inside the capped cell, so they uncap it and interrupt its reproduction," she said.

"In these bees, the mite doesn't get a chance to produce many offspring and so the levels stay low, so the bees can help themselves and co-exist with the mites."

Asian honey bees carrying varroa mites reached Australia in 2012, but the bees and mites were destroyed upon detection ( NSW Department of Agriculture, Fisheries and Forestry )

Dr Downey said the lesson for Australia was not to get on the 'pesticide treadmill', a choice made on mainland America when it faced its own varroa mite invasion.

"On the mainland, beekeepers were scared to lose their colonies and they didn't have many options, so they were very quick to grab whatever pesticide they could to kill the mite," she said.

"We've learnt now that it's expensive, it doesn't work. The mites develop resistance and we're contaminating out wax and honey.

"So in Hawaii we're trying to do our best to breed a better bee and reduce that chemical requirement.

"We're doing that on islands not only where there is varroa, but even the islands that don't have it.

"They are starting to prepare for this in case they get it, so they'll have resistant stock ready."

Dr Downey said the line of resistant bees she was adapting to Hawaiian conditions was first developed by the United States Department of Agriculture in a laboratory at Baton Rouge, Louisiana.

"There are many lines of resistant bees that people work with, and we don't even know why some are resistant," she said.

"Breeding is an ongoing effort, so you have to keep up the lines and keep improving them and right now the selection is based on the behaviour.

"The push right now is look for the genes using molecular techniques, so we can use marker assisted selection rather than having to do it in the field and count the number of varroa mites that are reproducing, which is much harder."