Mid Canterbury beekeepers have urged farmers and contractors to take care when spraying crops, following episodes of spray poisoning in the district.

"There have been crop spraying incidents where they may be using the wrong stuff or using stuff at the wrong time of day and there have been bee deaths as a result," said beekeeper Roger Bray, who has around 800 to 1000 hives across Mid Canterbury.

Heavy rainfall in December pushed everything back and in some cases this has affected many farmers' spray programmes.

Farmers have also been spraying more frequently in the wet weather to prevent disease and keep insects at bay.

"The wet weather has probably put spray programmes out of sync and what they have been able to get away with in the past they may not be able to get away with this year," Mr Bray said.

He advised farmers to spray at night when the bees were in their hives and inactive. He also urged them to stick rigidly to instructions on the labels of their chemicals.

Current thinking had meant bees were put in the middle of crops for pollination purposes but they had to be able to breathe.

"Seed companies have been advising us to put bees in the paddock but this may not be conducive. It may be better to put them 20m away," Mr Bray said.

Last year New Zealand Bee Industry Group (NZBIG) called for better communication among orchard owners in a bid to stop an epidemic of bee deaths in pip fruit areas.

Chairman Milton Jackson said hives were losing field bees because some orchard owners were not informing other owners they had sprayed their trees with carbaryl insecticide, used to control codling moth. Bees in the South Island were also under threat last year when a varroa incursion was suspected at a North Canterbury hive.