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QCRACKED PEARS My ‘Starkrimson’ pears, which ripen in February, develop these nasty splits. Fortunately the entire crop is not affected. Other varieties elsewhere in my garden and around the area are affected too but not quite so badly. I thought it could be dry weather but this year we have had good rain. BEN NICHOLLS, DUNEDIN

AUneven watering (usually a dry period followed by a sudden deluge or overgenerous irrigation) can cause pears to split, but in this case the skin blemishes and deep cracks are the result of pear scab.

Pear scab is a fungal disease more prevalent in wet conditions. Similar fungi affect other pipfruit. Leaves may become scabby or develop dark spots and fall early. Twigs may turn grey and crack. Fruit may have dark, dimpled spots, surface scabs or deep cracks. Fruit with either cracked or damaged skin is still edible but won’t keep well, so bottle or freeze what you can before rot sets in.

The fungus overwinters on fallen leaves so fastidious garden hygiene is the key to minimising the transfer of disease from year to year, and to other trees. Gather up as many fallen leaves, dropped twigs and pruned branches as you can and burn or bin them. Don’t compost diseased material or use it for mulch.

Increase air movement within the tree by pruning out the centre to form a vase shape or an open canopy. Clean and disinfect pruning tools before moving on to prune other trees.

Spray with liquid copper in winter or lime sulphur at bud movement. Spray regularly with Yates Fungus Fighter from bud break to fruit set. Close to harvest or for organic gardeners use copper hydroxide or Grosafe Free Flo Copper.

Healthy plants growing without environmental stresses are more resistant to disease. Keep the tree well fed and evenly watered. Add mulch (not touching the trunk) and dose with a monthly seaweed tonic. Barbara Smith

QANT TRAILS Ants are swarming all over my sweetcorn. How can I get rid of them? LIZA KARIM, AUCKLAND

AAnts can be a nuisance in the garden, hollowing out nests in plant pots or running up your arms and legs while you are weeding, but they can be useful too. If you notice scouting ants exploring a plant, check to see where they’re going. Ants feed on the sweet honeydew excreted by sapsucking insects, so following a trail may lead you to well-hidden pests.

In this case the ants are heading for the aphids clustered among the leafy husks covering the corn cobs. If you get rid of the aphids, there will be no honeydew to attract the ants.

Aphids are usually seen on corn as the tassels develop. If the infestation is severe, pollination can be reduced leading to poorly developed gappy cobs. Honeydew can also feed a black layer of sooty mould which reduces the health of the plants too.

Your corn is nearly ready. Don’t spray because of the withholding period before it’s safe to harvest the corn. Wash off the aphids with the hose or some soapy water or squash them with your fingers. You’ll need to check every day as aphids reproduce parthenogenetically and viviparously, meaning that a single female can produce offspring without a male and the babies are born live, rather than hatching from eggs. Keep checking to see if the infestation has returned, as aphid populations build up rapidly.

Track the ant trail back in the other direction to ground zero, the nest, and deal to them there too. Barbara Smith

QROGUE LILY This top-heavy lily has a flat stem nearly 10cm across and it has many more buds than usual. SALLY FOX, PAPAMOA

AIt’s been a wonderful summer for lilies but this one is even more floriferous than most.

It is an example of an abnormal growth pattern called fasciation caused by damage to the growing tip of the stem.

Fasciation can be caused by viral infections, chemicals (herbicides), genetic mutation, or as a result of injury from insects, animals, frost, wind or cultivation. The growing tip or apical meristem is where cells are actively dividing to form new plant tissue. Damaged cells divide multiple times and may form flat or tubular stems, and crested or multiple blooms.

Signs to look for are flattened, fused shoots, which look like several stems joined together, and multiple, misshapen flowers in a ring around a normal central bloom.

It occurs in many plants including delphiniums, foxgloves, roses, cacti, heleniums and euphorbias but is particularly spectacular in lilies. A fasciated lily stem which would normally have three to five flowers can explode into a giant ball of more than 100 flower buds.

Fasciation occurs in fruit and vegetables too. Examples are double strawberries and Siamese twin cucumbers and courgettes.

The abnormal growth is usually limited to one stem and won’t necessarily recur in the same plant the following year. Barbara Smith