Rock Garden Plants

Fruit and veggie varmints

IF YOU LOVE A JUICY, sweet plum picked right off the tree, you're not alone. Some insects attack fruit crops with the same sort of gusto you might apply to a bowl of fruit salad. If you plan on growing fruit, look out for codling moths, pear midge, pear and cherry slug worm, and sawflies. There are also many unwanted vegetable visitors including caterpillars, cutworms, carrot root flies, and pea moths.

Apple saw fig

The adult sawfly lays eggs in fruitlets just at flowering time, and on hatching, a grub leaves a characteristic ribbon-shaped scar on the apple surface, before tunnelling its way into the heart of the fruit to feed on the central core. This normally causes the fruit to drop in June or July. When the larva is fully fed, it'll depart via an exit hole, crawl into the ground to pupate, and emerge later as an adult.

Once sawflies are within the fruit, they are protected from all chemical controls. So it's not worth spraying the fruit. You will not harm the insect, but the spray might harm anyone who eats the fruit.

Codling moths

The most common cause of wormy apples, these whitish-pink moth larvae also feed on pears. When the codling moths have invaded, you'll see small holes in the fruit skin with dark brown, crumbly matter around the holes. As if the larvae damage wasn't bad enough, the holes are perfect sites for bacterial and fungal growth. The larvae drop to the ground or crawl down the tree trunks when they are ready to spin cocoons. They may over-winter under tree bark or in garden litter. Severe codling moth infestations can totally destroy a fruit crop. Damage is worse in years that have warm, dry spring-time weather, because the moths lay more eggs.

To protect your garden, clean up garden fruits as they fall, and place rejects in a covered container for eventual disposal. Remove weeds and other debris to eliminate larvae hiding places.

Pick off and destroy fruitlets showing signs of damage before the larvae escape into the soil. If infestations are severe, spray the tree branches with an appropriate insecticide, reading the instructions carefully.

Pear midges

The early symptom of the pear midge is when small fruitlets become deformed and blackened and fall off the tree in late spring and early summer. With a bad infestation, all the fruit can be lost. On splitting the fruit, you'll see a large central cavity and numerous tiny white grubs up to 2 millimeters long. On small trees, pick off and destroy infested fruitlets before the maggots complete their feeding. You can stop the adult flies laying eggs by spraying with an appropriate insecticide at the white bud stage of the tree, which is when you can see the petal color but before the flowers have started to open.