There’s an old joke: What’s worse than finding a worm in your apple? Finding half a worm. For an apple-tree-owner, worse still is finding a worm – or worm holes – in every single fruit on your tree.

LOS ANGELES - Next to a copy machine on the 10th floor of the city's public works building sits a plastic bin filled with worms wriggling in rotting lettuce. Public servants walk by without even ...