Far more threatening to the bee-driven economy are varroa mites, ticklike parasites that first showed up in the U.S. in 1986.

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Conversely, where Varroa mites are not present, bee populations thrive even when neonicotinoids are heavily used.

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"I think it is amazing that despite all the years of intensive study there are still massive discoveries to be made about fundamental honey-bee physiology such as the ability to paralyse small insects and mites, " he said.

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Lovett believes that mites can only have been imported by beekeepers as no host bee carrying the parasite could have made it to the country on its own.

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The British Bee Keepers' Association recommends that Varroa products be rotated to ensure that the mites have little chance to develop resistance.

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"When the mites are actively developing, they do so in the brood cells where the bee larvae are growing, " she added.

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Twenty thousand Florida bee colonies, or 8% of the state's commercial colony population, succumb to mites each year.

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