Fruit disease
Now that we’ve had some rain, it reminds me that we live in a temperate climate that breeds disease. This drier year has been good for many fruits, but fruits often get diseased even before they’re ready to eat. Here are a few common diseases and methods to deal with them.
Black spot: Occurs as leaf spots on apples, pears and quince in spring and later on other fruit. This fungus is active in wet weather and becomes dormant when dry. Plant resistant fruit varieties at correct spacings to ensure good airflow around trees. Prune shelterbelts to help air movement too. Irrigate with drippers rather than overhead sprinklers. Mulch around trees in spring to cover any bare soil, where the fungus overwinters. Remove affected fruit and leaves and destroy. Prune for shape that allows good airflow. Spray with copper oxychloride in winter and spring.
Brown rot: This fungus affects blossoms, twigs, and developing fruits of peaches, nectarines, apricots and plums. Wet weather aids its spread in spring. Adopt resistant varieties, good spacing and open airy situations. Remove any shrivelled fruit (mummies) from trees and prune cankered twigs and burn. Summer prune after fruiting into an open vase shape. Copper spray in winter and spring, especially at flowering and when fruit forms.
Silver leaf: A fungal pathogen that affects lots of different plants, particularly stonefruit, apples, roses, poplar, willow and escallonia hedges. Leaves turn silver and become smaller, then infected branches die back. Bracket fungal bodies form on dead branches during wet weather. Prune out all infected wood and burn (clean pruners with meths between trees!). Check shelterbelts too. Prune in summer or autumn when dry. Insert trichodowels into trunk when sap is flowing (best in spring).
Phytophthora: A wilt fungi that spreads through soil water to susceptible plant roots like citrus, avocado, and ornamentals like rhododendrons. Leaves droop, turn yellow, stems develop “collar rot” and the whole plant often dies. Select resistant rootstocks where possible. Plant with trichoderma powder for ongoing protection (ask at Wrightsons). Avoid ground with dry summer and wet winter soils. Ripping the subsoil and adding gypsum may alleviate this. Remove and destroy infected plants. Don’t replant identical species in the same spots. If all else fails, use phosphite fungicide injected into the trunk’s vascular tissue (for avocados call Brett Hutchinson 525 8342).
Peach leaf curl: This fungal disease of peaches and nectarines occurs in spring during cool wet weather. New leaves become swollen and distorted, and shoots can die. It goes away in dry weather. Buy resistant varieties. Remove affected leaves and burn. Prune off dieback. Spray with copper after summer pruning, before bud burst and 10 to 14 days later in spring.
Successes with fruits can depend on the weather and season, another reason to plant a good selection.
Fruit care
Sow orchard understorey plants. Clear mulch first.
Water fruits and keep all fruits well mulched.
Support fruit-laden branches.
Summer prune after fruiting: when sunny prune out water shoots low on trunks or in fruit tree centres, especially stonefruit. Prune out old berryfruit canes.
Watch for silver leaf. Prune out affected branches. Apply trichoderma to cuts. Insert bio dowels into trunk asap.
Tip figs once fruit buds present to improve fruiting.
Put bands of corrugated cardboard around fruit tree trunks. Remove and burn every two weeks to limit moth caterpillars. Barrier paste on bands helps trap them.
Strawberries need fortnightly liquid fertilising with comfrey. Let runners grow now to replace old plants.
Spray fruits with liquid seaweed as a tonic.
Also spray citrus with all purpose oil for scale insect and aphid (or use garlic and pyrethrum).
Prune citrus when harvesting.
Prune grape shoots back to two leaves past fruit.
Herb Care:
Keep harvesting to stall flowering.
Sow basil (indoors), coriander and dill direct fortnightly.
Plant parsley.
Water, weed and mulch.
Vegetable care
Harvest pumpkins and melons when tendrils and stalks brown off. Collect dry beans for seed.
Stake and save seed from best salads, silverbeet, etc.
Keep weeding and make lots of compost.
Prepare ground for broad bean sowing next month. Add lime and compost.
Plant winter brassicas in a fertile bed. Cover to protect from pests (netting or shade cloth).
Sow/plant salads and winter greens for ongoing supply.
Liquid fertilise in the morning once a week.
Spray Bt onto brassicas vs caterpillars.
Sow and plant flowers to attract beneficial insects.
Hothouse: Liquid fertilise weekly. Replace yellow sticky cards/bands for whitefly. Keep well ventilated. Spray diluted milk solution vs powdery mildew.
For transplanting: All seeds 28 March. Leafy greens (summer spinach, silverbeet/chard, lettuce, endive and cabbages)(best 26 March). Broccoli, cauliflower. Flowers, eg violas.
Sow direct: All seeds 28 March. Mesclun salad. Peas. Radish, spring onions, spring carrots, swede and turnip (also 30th March-1 April). Flowers, eg alyssum.
Plant: 5–18 April. Salad greens, silverbeet/chard, spinach, and cabbages. Flowers, eg tulip bulbs.
General garden care
Prune trees and shrubs after flowering, including roses.
Make comfrey liquid fertiliser.
Collect seaweed/seagrass.
Sol Morgan, GroWise Consultancy
