Bees, pesticides, and unintended side effects
Pesticides are designed to kill insects that damage crops – harming bees is an unintended side effect. The chemicals can harm bees directly or indirectly, depending on how they’re used. If pesticides are sprayed on flowering plants that are then visited by bees, they will pick up some of the spray, which can lead to weakness, ill health, or death. When used at an earlier stage, the chemicals can build up in the plant, and pass to bees when they gather pollen or nectar. In some cases, entire colonies are killed when pesticides are sprayed nearby, or when wind-drift scatters the chemicals over a large area.
The effects on bees range from immediate death to damage over time – when pesticides build up in their systems, they can end up vulnerable to disease, with shorter lifespans and disrupted brood cycle. These effects weaken colonies and lead to lower bee numbers in general.
Although many pesticides cause harm, neonicotinoid is one of the worst offenders. A number of countries are looking at ways to control or ban the use of this pesticide in particular.
The EU and a number of European countries outside the union have recently banned the use of neonicotinoid. New Zealand has not followed yet, although there has been some discussion about doing so.
Farmers argue that, because this form of pesticide is so effective, a ban would force them to use higher volumes of other chemicals to get the same effects. They also believe that the current rules around neonicotinoid use are effective.
At the moment, growers are governed by a strict set of rules around pesticide and particularly neonicotinoid use. They are not allowed to spray near hives, on crops likely to be visited by bees, or when bees are likely to be foraging. They can’t use sprays when flowering crops or weeds are nearby, and must avoid spraying plants in bud or flower.
Of course, these rules aren’t always followed by every single farmer or grower, but they do seem to be working for New Zealand’s bee population so far. A 2016 survey showed a hive loss level of 9.8% – low compared with international figures.
Doing more for bees
Although New Zealand’s pesticide use appears to be under control, and our bee population seems healthy, it’s important not to be complacent.
You can help by keeping up with the rules around pesticide use, even in your back garden. Think about whether you need to use pesticides at all, and if you do, make sure you don’t use them on flowering plants or around beehives.
If you’re a beekeeper, you can protect your hives in a number of ways – get nearby farmers to warn you about chemical use, locate hives in sheltered areas to avoid drift, provide plenty of clean water, and watch for signs of pesticide poisoning.
Maintaining a strong bee population takes a lot of hard work and awareness from beekeepers, farmers, the government, and the general population. As new pesticides are created and introduced, we all need to keep an eye on their effects – our bees are relying on us.