Mangos, bees and agriculture threatened

Cheating with chemicals

The market has its ways to compensate for the variability in quality and lack of timeliness of supply. The means are not always clean. Growers increasingly rely on chemicals like calcium carbide to ripen immature fruit—though the chemical is banned throughout most of the world due to health reasons.

But the greater risk is in pesticides and anti fungal chemicals that growers are forced to turn to keep crops fruiting. Take the beleaguered almond groves of California.

Almonds too are threatened

More than 80 percent of the almonds consumed on Planet Earth hail from California groves, groves that depend upon the honeybee to pollinate them. Now the bee populations are threatened. Somewhere between 15 and 25 percent of the beehives in almond groves suffered “severe” damage during this year’s bloom, ranging from complete hive collapse to dead and deformed brood (the next generation of bees incubating in the hive).

The blame seems to be placed with a deadly cocktail of pesticides—insecticides and fungicides—called Pristine, marketed by the German chemical giant BASF, and Diflubenzuron, marketed by Chemtura. Almond growers trying to combat fungus that threatens their groves are combining the two pesticides along with substances called adjuvants—which are used to enhance the performance of pesticides—and then spraying the resulting cocktail on crops. killing bee populations and threatening the crops. No pollinators, no almonds.

Bees are threatened by more than just pesticides

Honey bees aren’t the only pollinators, take the case of the bumblebee. Global warming is serving to “crush bumblebees in a kind of climate vice”, according to the leader of a team that has revealed a dramatic shrinkage in the range of these crucial pollinators.

As temperatures rise, the southern limits of many North American and European bumblebee species’ ranges are moving north — by as much as 300 kilometres in some cases. But the northern edges of the bees’ ranges are staying in place, leading to an overall contraction of the insect’s’ habitat.

Jeremy Kerr, a biodiversity researcher at the University of Ottawa in Canada, and his colleagues collated more than 400,000 observations of bumblebee species collected in North America and Europe between 1975 and 2010. When the researchers charted the locations of these bee populations over time, they found that many of the 67 species analysed were retreating northward from their southern limits.

“For every species that is doing great, there is one or two species that is declining and others that are not moving at all,” says Kerr.

This shift has also been observed in other species, such as butterflies. But unlike butterflies, bumblebees have failed to extend the northern boundaries of their ranges, into territory that is now habitable for them due to climate change, the latest study finds.

“Bumblebee species across Europe and North America are declining at continental scales,” says Kerr. “Our data suggest that climate change plays a leading, or perhaps the leading, role in this trend.”

Leave a Comment

Your email address will not be published.