A bee breeding project that promises another non-chemical option for varroa control is gaining ground.
Nelson company, Rainbow Honey is continuing a programme started by Plant and Food Research to build up populations of honey bees that control the killer parasites in hives by interfering with their breeding cycle.
The bees carry a genetic trait, called the varroa sensitive hygienic or VSH trait.
Project leader Rae Butler says they've been building up VSH bee numbers in 80 trial hives to the stage where they've been able to reduce the number of chemical treatments needed to keep varroa under control.
Ms Butler says they're now looking to extend the programme and fund on-going research by forming partnerships with other bee-keepers and some have already joined up.
A Plant and Food scientist who started the programme 10 years ago, Michelle Taylor, is continuing to provide guidance.
She says if the numbers of VSH bees can be built up in hives through the country it could provide beekeepers with a way of countering the growing problem of varroa resistance to chemical treatments.