Hi, I lost my whole lemon crop to blue mould last season - I suspect guava moth may have damaged the skins and let mould in? Now my ripening lemons are showing the same thing, 3 falling off the tree with mould - could I save the lemons by harvesting them before they ripen - the tree is laden?

Hi Sheryl, blue or green mould on citrus fruit is usually a problem once it is picked, and not while it is still on tree, it enters the fruit after harvest through damaged skin. The fungus lives in the soil and can be prevalent in warmer regions. The best thing to do to prevent it becoming a problem each season is to pick up fallen fruit from the ground, and infected fruit on the tree. Dispose of in the rubbish, don't leave the rotting fruit on the ground or compost the fruit as the fungal spores will lay dormant in the soil until conditions are right - warm, humid weather. A copper and sulphur spray may help reduce the problem, maintain a regular spray programme through autumn, winter and once fruit has set, not while the tree is flowering. Talk to your local garden centre for other suitable controls. If you can, pick the fruit before it goes mouldy on the tree, if the fruit gives in your hand it is ready to pick. Improve air circulation around the tree, remove small twiggy growth, broken branches, crisscrossing branches, cut back vigorous water shoots. Lianne.