Many plants in the garden, particularly those in the cucurbit family (melon, pumpkin, squash, and cucumber) will have leaves covered in powdery mildew, because of the high humidity of recent weeks.
Powdery mildew appears as a white coating on the leaves and, once established, can be difficult to eradicate.
The leaves will eventually die off. Affected leaves can be cut from the plant. Larger outbreaks can be sprayed with a mixture of one-part fresh milk to five parts water, repeated weekly. The benefit of using this type of spray is that it will control fungus without harming useful ladybirds. Avoiding applying water to leaves, particularly late in the day, will also help control the disease.
One of the useful ladybirds in the garden is a natural predator for powdery mildew. It is active in gardens at the present time but it is one that may be easily overlooked.
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The Fungus-eating Ladybird might be mistaken for a harmful variety of ladybird, but they are quite different in appearance. The Fungus-eating Ladybird has zig-zag bands of bright yellow and black on its wings.
Fungus-eating Ladybirds are very fast moving insects and the active fliers. When disturbed, they usually employ the drop and fly-away method to escape.
The larvae of the Fungus-eating Ladybird may also be in evidence at this time. They grow up to 8-10mm and are creamy white in colour with lines of black dots on their back. They move quickly when disturbed. Adults may also feed on aphids and black mould. The larvae also feed on the mildew.
The presence of insects such as the Fungus-eating Ladybird is a good example of the preference that should be given to building up populations of natural predators, rather than spraying the garden with harmful insecticides.
The yellowish ladybirds with 26 or 28 spots are the only pests of the ladybird family. They eat the leaves of stressed plants. They can be pulled off leaves by hand. Another tip for controlling the leaf eating ladybird is to control the blackberry nightshade weed, which is a favourite food plant.
Quite often infestations start on the weed before they move into the garden. Removal of these weeds will help in control of these ladybirds.
Native shrubs benefit from a pruning. They are often promoted as low maintenance plants that can virtually be forgotten once they have been planted. In general, this is true, but they certainly benefit from some attention. Once established, they require less attention, water and fertiliser than most exotic plants.
However, if natives are left unpruned, they tend to become rather leggy plants and produce fewer blooms. Rather than cutting the plant back severely when it reaches this stage, it is preferable to maintain regular, light pruning from an early stage.
The new shoots that result from the pruning will carry more flowers, and the plant will become less susceptible to damage from borers or fungal disease.
When individual flowers on grevillea varieties such as Robyn Gordon, Moonlight and Superb have finished, a blackened stalk will remain. The stem containing this stalk should be removed to just above a new bud. This can be identified by its young, new leaf growth.
Following a more prolific seasonal flush of flowers, hedging shears can be used to lightly shape the bush, ensuring all old flower stalks are removed. Older plants can be tidied up with harder cutting.
Bottlebrush (callistemon) species should have their flower heads removed as the plant concludes its flowering season. Again, cut back to just above a new bud. Secateurs or hedging shears can be used, depending on the size of plants. This will allow the bush to be shaped as desired.
Lillypillies have become very popular plants to include in garden plantings. They are available in many different sizes and growth habits, with many producing attractive flowers. The flowers are followed by equally attractive fruits, ranging in colour from pinks through to deeper purples.
As Lillypillies are often selected for specific purposes, including lower and taller hedging, topiary or specimen plants, pruning is essential in order to maintain their desired shape. Regular, light pruning from an early stage will result in healthy, dense growth. As some are susceptible to insect damage, affected leaves should be removed. Sharp hedging tools, whether hand-operated or electrical, will produce the best results.
The pruning of lillypillies is best left until flowers and fruits produced during summer have finished.
Geraldton Wax plants will be covered in new shoots now. Tip pruning, pinching back the ends of the new growth, will result in increased numbers of flowers. Watch for the appearance of the new season flowers, and then cease tip pruning.
Pruning of native plants can be used to maintain healthy plants. Certain natives, such as leptospermum, commonly known as Tea Trees, and Melaleucas, are subject to attack by the Webbing Caterpillar. This pest creates cocoons in the inner parts of the plants. The cocoons will hold large numbers of caterpillars that will quickly decimate the leaves on the plant, leaving it vulnerable to other pests.
Because the webbing in the cocoon creates an almost impenetrable barrier, sprays cannot be used for control purposes. The best way is to cut the webbing and branches used as for the structure, from the plant. New, healthy shoots will soon be produced.
WHAT YOU CAN DO NOW
- Order bare-rooted fruit trees and prepare the holes for winter planting.
- Overcrowded clumps of perennials may be dug up and divided now, producing healthy newer plants that will produce good flowers.
- Check zygocactus plants, feed them and move them to a prominent position when flower buds begin to form.
Maitland and District Garden Club