As you may well appreciate it is impossible to provide complete coverage of all of the pests and diseases which may affect the home garden. We have compiled a list of the most common, along with suggested remedies for your reference. For further advice please contact your local nursery or gardener.
Peach and cherry Aphids
Woolly Aphids
Aphids
Woolly Aphids
Woolly Aphids
Only affects apples. Observed as a white fluffy appearance like cotton wool. The aphid is a sticky black insect underneath this “wool”. It is a sap sucker that weakens the plant. Very light infestations can be dislodged with a jet of water from the garden hose. On heavy infestations spray with summer oil as required. Granny Smith apples are very susceptible to woolly aphids. A summer infestation may be treated with Malathion.
Aphids
Peach & Cherry Aphids
Peach & Cherry Aphids
There are two types—green and black. They are often mistaken for curl leaf as the aphids cause the leaves to curl. The presence of ants is often an indication of an Aphid population. Close examination will reveal the aphids in the deformed leaves. When sheltered they are difficult to eliminate. Use pyrethrum as required or another insecticide.
Bitter Pit
Caused by a deficiency in calcium. The fruit appears pitted with the flesh a brown colour. It can be due to:
- Excessive shoot growth that competes with the fruit for the calcium.
- Overly-large fruit during the off-year.
- Moisture stress that causes water to be drawn from the fruit to the leaves taking the calcium with it.
- Soil imbalances of potassium and/or magnesium.
Black Spot
The disease is spread by spores that are released into the air from spring rains. If the leaf or fruit remains wet for about 9–10 hours infection can occur. It can be controlled organically with copper oxychloride or sulphur. Spraying at bud burst and several times at 14-day intervals is usually sufficient. Do not use copper oxychloride one month after bud burst as it can defoliate the tree. This disease is not usually a problem on the Adelaide Plains. Watch for dark green, velvety looking spots on fruit and leaves.
Brown Rot
Generally not a severe problem on the plains. Usually only occurs during wet weather when the fruit is close to maturity. Make sure several fruits are not touching as this is where it usually occurs. Use sulphur or an appropriate fungicide suggested by your local nursery.
Cherry Slug
Also attacks pears and quinces, and is usually apparent midsummer. Look for black leech type slugs on the leaves. They will eat the fleshy part of them, leaving the skeleton of the leaf behind. In small numbers they are easily controlled. A dusting of derris dust or spraying with pyrethrum when required will easily control them. Carbaryl or Confidor may also be used.
Codlin Moth
Use carbaryl from mid-November and then spray monthly. Garlic sprays used fortnightly in conjunction with pheromone traps will especially control this pest. Corrugated cardboard placed around the branches of the tree during spring, and then removed and burnt in the autumn, will also decrease the moth population. Destroy all infected fruit. Without regular spraying Codlin Moth is the worst problem for apples and pears.
Curl Leaf
Prevention is the key to curl leaf control because once the infection has occurred there is no means of eradication. Correct timing of the spring application is essential. The first spray should be in spring at bud swell with at least two further sprays at weekly intervals. Another spray at leaf fall in autumn is also beneficial. Use copper oxychloride.
Curl Leaf
Prevention is the key to curl leaf control because once the infection has occurred there is no means of eradication. Correct timing of the spring application is essential. The first spray should be in spring at bud swell with at least two further sprays at weekly intervals. Another spray at leaf fall in autumn is also beneficial. Use copper oxychloride.
Curl Leaf
A serious airborne infection that at the very least causes a decline and complete ruin of the fruit. High rainfall areas like the Adelaide Hills, South-East, Southern Vales, and to a lesser extent the Adelaide Plains are most affected. During the wet weather the spores enter the pruning wound, germinate and slowly grow down the limb until the tree is killed. When the fungus reaches the main trunk there is nothing that can be done and the tree will eventually die. Each year spores are discharged after rain, and will quickly infect pruning cuts if untreated. Once the spores have germinated in the wound chemical treatment will not prevent the fungus from attacking the limb.
Controlling gummosis…
Prune in autumn when the weather is still warm, but not if rain is expected. Reduce pruning to a minimum to treat all cuts with a fungicide-based grafting mastic. Burn all infected limbs as soon as pruning has been completed. When moving dead trees make sure no part of the trunk remains above ground level. If caught early and it’s in only small branches, removing them can
improve the chances of the tree surviving. Cut down until the wood is a nice white colour.
Prune in autumn when the weather is still warm, but not if rain is expected. Reduce pruning to a minimum to treat all cuts with a fungicide-based grafting mastic. Burn all infected limbs as soon as pruning has been completed. When moving dead trees make sure no part of the trunk remains above ground level. If caught early and it’s in only small branches, removing them can
improve the chances of the tree surviving. Cut down until the wood is a nice white colour.
The symptoms…
The disease is usually noticed as a wilting of the leaves during summer. The fruit ripens earlier than the rest of the tree with the limb dying before the end of the season. Gumming of the infected limb is also noticeable, but this does not mean that all gumming of branches represents gummosis. In fact, it is nature’s way of healing. Just as we bleed when we cut ourselves, so do trees when they have been injured. Gumming of the branches is also a symptom of bacterial canker. If the gum is clear in colour there is usually no need for concern. However, if the gum is a yellowish brown the chances are the tree has developed
either gummosis or bacterial canker.
The disease is usually noticed as a wilting of the leaves during summer. The fruit ripens earlier than the rest of the tree with the limb dying before the end of the season. Gumming of the infected limb is also noticeable, but this does not mean that all gumming of branches represents gummosis. In fact, it is nature’s way of healing. Just as we bleed when we cut ourselves, so do trees when they have been injured. Gumming of the branches is also a symptom of bacterial canker. If the gum is clear in colour there is usually no need for concern. However, if the gum is a yellowish brown the chances are the tree has developed
either gummosis or bacterial canker.
Powdery Mildew
Affects new growth causing a silvery appearance. Unless the problem is severe little needs to be
done. Check with your local nursery for a range of suitable control products.
done. Check with your local nursery for a range of suitable control products.
Red Spider
Look on the underneath side of the leaves for the small mite. They have two distinct markings on their back that can be easily seen with a magnifying glass. Infestations usually start late December. Watch for the bronzing or ‘dusty’ appearance of the foliage. Pear leaves go black. Use pyrethrum or sulphur.
Thrips
Very small and difficult to see with the naked eye, they are long and slender with a black appearance. Usually five to ten thrips per bloom can be tolerated. Can be beneficial in most cases in the home garden because it helps to thin crops. If blossom is very light use Pyrethrum as required. Generally not a problem.
Chemical safety
When using garden chemicals follow these simple rules:
- Regard all chemicals as potentially dangerous.
- Read all of the label carefully and follow the instructions closely. Use the recommended quantities per mixture.
- Use chemicals only for the purpose stated on the label.
- Mix chemicals in an open, well-ventilated area. Wear full-length clothing, a face shield and rubber gloves when spraying.
- Avoid drift on yourself, other plants, animals, etc.
- Store garden chemicals only in the original containers, away from food and out of reach of children and animals.
- Wash thoroughly with soap and water before drinking or eating after handling.