"Major supermarkets, in meeting consumer expectations, will often reject entire crops of perfectly edible fruit and vegetables at the farm because they do not meet exacting marketing standards for their physical characteristics, such as size and appearance, " the study said.

CNN: World wastes half its food, study finds

If the prices of vegetables, fruit and other crops are more flexible than other prices, food inflation may be an early warning of an overheating economy.

ECONOMIST: Price rises in China

But some of the crops are destroyed and most of the peach trees are left with no fruit on them.

BBC: Return to Swat: 'Alone in the village'

It specializes in so-called nonrow agricultural chemicals--herbicides and pesticides for fruit and nut trees instead of crops like corn grown in rows.

FORBES: Chemical Balance

The teaching of science stimulates the local economy as farmers become more likely to try out new crops, such as different types of vegetables, or fruit for export.

ECONOMIST: Research from the ground up

In industrialised nations, such as the US and in Europe, many farms employ the services of commercial hives to pollinate fruit trees and food crops, and ensure they harvest adequate yields.

BBC: 'Pollination crisis' hitting India's vegetable farmers

"We've had crops left on the vine or fruit left on the tree because of a shortage of workers, " Norton said.

WSJ: Schumer: Immigration bill helps Northeast farmers

The devastating effect of the bugs' appetite became apparent to farmers in 2010 when swarms destroyed fruit crops across several states in the mid-Atlantic region.

BBC: US & Canada