May is the time to take action against codling moth, which attacks apples and pears, and sometimes walnut and quince.

The small, nondescript moth is seldom noticed as it flies in the evening. The first ones appear in late May and they are still about until early August. The females lay eggs singly onto developing fruitlets. In two weeks the tiny caterpillars hatch and tunnel into the fruit, eating out the core and leaving brown droppings known as frass.

When mature, they tunnel out again and pupate over winter in cracks and crevices. Damaged apples may be unappetising, and are prone to rotting so cannot be stored, though they are perfectly edible if the damaged parts are cut out.

You can interrupt the moth's breeding cycle by trapping. Codling moth traps, which look like miniature plastic tents, contain a chemical that mimics the scent produced by females. This attracts the males which are then caught on a sticky pad.

These traps were originally devised to monitor moth levels to help growers time their application of insecticide sprays more effectively. But they do catch enough moths to make a difference to levels of damage and there are no

suitable insecticides available to amateurs even if you wanted to use them.

Hang one trap to every five trees from May to September. You can further reduce the moth population by tying sacking or corrugated cardboard around the branches in July to attract pupating caterpillars.

It can then be removed in September and burned or consigned to the bin.

Jobs of the week:

* It's too late to sow onions, but you can still sow all other vegetable crops this month

* Net strawberries before the fruit starts to show colour, to keep off birds. Use wire netting if squirrels are a problem.

* Divide primula and polyanthus after flowering, and move any that are badly placed

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May 14, 2003 10:00