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Onion Grass (Weeds)
Description: Onion Grass (Romulea rosea var Australis) is quite different from Onion Weed although both are equally difficult to get rid off. Onion Grass is a perennial with narrow leaves. It looks like grass until you try remove it and find a small brown corm about size of a hazelnut. It has pretty star shaped pink-violet flowers with a yellow centre that flowers between August and November. It spreads very fast, by seed in the air and water or corms and cormlets in the soil.
Affects: It tends to be a problem in area of compacted or neglected soil. It is often a problem along grass verges. Onion Grass in poisonous to cattle.
Solution: Remove by hand ensuring that the small brown corms are also removed. If in your lawn or grass verge regular cutting will weaken the plants and reduce the opportunity for the plants to flower.
There are several selective and non selective herbicides registered to control onion grass. This is not recommended in the domestic situation as the herbicides may not only affect the native plants, the herbicides recommended for use during flowering are likely to have a harmful affect on the bees.
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Onion Weed (Weeds)
Description:
Onion weed is sometimes called false garlic because of 'bulblets' that grow around the base of the bulb. Each bulblet can grow into a new plant and removing all them can be very tricky. The leaves can initially be mistaken for the leaves of daffodils but the flowers are quite different, they are white and form in clusters at the top of a single stem
Affects:
Solution:
Remove by hand whilst the bulblets are still tightly attached to the main bulb. You'll need t long trowel to open the soil before pulling them out - or the foliage will just snap off, leaving the bulb in the ground. If the onion weed is in your lawn a combination of regularly watering, feeding and mowing of the lawn may help. Always remove the flowers before they have a chance to go to seed.
Alternatively you can apply a spot treatment by painting a non selective herbicide like Zero (glyphosate) onto the leaves.
Note: Many chemicals sold can be harmful to insects as well as some animals and in some cases, humans.
Always read the manufacturers instructions and warnings before you begin and use as directed.
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Oxalis (wood sorrel) (Weeds)
Description: Sometimes called Shamrock or Creeping Oxalis - a low growing soft leaved (trifoliate leaflets) weed with pretty yellow, purple or white flowers. Very invasive and found in lawns, flowerbeds and pot plants.
Affects: Steals nitrogen from neighbouring plants
Solution: Remove by hand using a trowel to loosen the soil first, follow the stolons and remove each developing root. Keep lawn healthy and well fed during the warmer months.
Use a broadleafed herbicide on lawn.
Note: Many chemicals sold can be harmful to insects as well as some animals and in some cases, humans. Always read the manufacturers instructions and warnings before you begin and use as directed.
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Paspalum (Weeds)
Description:
Paspalum is a tufted perennial grass that grows up to 150 cm. and is often dormant in winter. It grows well in patchy lawn, on roadsides, in orchards, plantations and vineyards.
Affects:
Solution:
They can be removed by making sure all the upper plant including the crown has been removed. In lawns improve the health of the lawn by regular water, feeding and mowing. Mowing will not get rid of paspalum but it will encourage a denser lawn making it harder for paspalum to establish.
Use a selective spray on lawns and spot spray with a non-selective herbicide on smaller areas.
Note: Many chemicals sold can be harmful to insects as well as some animals and in some cases, humans. Always read the manufacturers instructions and warnings before you begin and use as directed.
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Petty Surge - Radium Weed - Cancer Weed (Weeds)
Description: Petty Surge (Euphorbia pelplus) is a shade loving annual weed common is garden beds, roadsides, fields and woodlands. It can grow to about 30cm in length and has small oval shaped leaves alternately along its stem. It has yellow- green flowers from spring to late Autumn The stem contains a milky sap which is currently being studied for the treatment skin cancer, leukaemia, warts and sunspots.
Affects:
Solution: As with all annuals the aim is to control them by removing the plants before they have time to set seed. Once the seed pods have formed the sensitive nature of the pods means that the pods explode and release seed as the plants are removed.
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Pimple Psyllids (Pests)
Description:
Pimple Psyllids are small sap sucking insects. They feed on the underside of new leaves. They are quite easy to identify as they feed red lumps 'galls' appear on the leaf's upper surface above the indentation on the lower surface containing the 'scale like' insect.
Although they look unsightly they don't seem to affect the overall health of the plant.
Affects:
All Lilly Pilly. Particularly susceptible are Syzygium coolminianum, Syzygium australe, Syzygium paniulatum .
Solution:
Plant species that seem to be more resistant to psyllid attacks ie Acmena smithii and Syszgium luehmannii.
Watch the new growth and spray with a systemic insecticide like Confidor but only when the plant is not in flower.
Systemic insecticide sprays have proved effective. Yates Confidor is no longer recommended as it is now known that Confidor is harmful to bees and should only be used when a plant is NOT in flower.
Note: Many chemicals sold can be harmful to other insects as well as some animals and in some cases, humans. Always read the manufacturers instructions and warnings before you begin and use as directed.
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Pink Wax Scale (Pests)
Description: Pink Wax Scale adults looks like small greyish pink turtles is found on the midribs and lateral veins and occasionally soft stems. Pink Wax Scale is a soft scale and produces a thick sweet secreta 'Honey Dew' that encourages both ants and sooty mold. The young nymphs 'Crawlers' are small red and mobile - this is the most vulnerable stage of the Pink Wax Scale life cycle - the ants herd and protect them from any predators.
Affects: Wide range of plants - Syzigium (Lilly Pilly), Ivy, Holly, ferns, citrus, figs and Pittosporum. Tends to be worse in spring and autumn. Plants are weakened in two ways firstly because the scale sucks sap from the leaves reducing the energy producing chlorophyll and secondly the thick layer of sooty mold prevents the sunlight reaching the leaf and allowing the plants to photosynthesize.
Solution: The solution chosen will depend on the size of the infestation and the affect it is having on the plant. If there are only few present then the scale can be wiped off.
At the crawler stage Pest Oils can be used and 'TangleFoot' to form a barrier against climbing insects including the ants.
Adults - if there are too many to wipe off then use a systemic insecticide - it may take 2-3 applications
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Potato and Tomato Blight (Late Blight) (Disease)
Description:
This is a disease caused by the fungus Phytophthora infestans The leaves develop dark marks, the leaves soon shrivel and turn brown. The stems may develop brown lesions.
The tomatos develop dark patches and the mature fruit start to decay as it ripens. The potato tuber develop a reddish-brown decay below the skin and the tuber starts to rot. Like all fungal diseases blight it always worse in warm damp conditions.
Affects:
Affects potatoes and tomatoes.
Solution:
All disease plant material should be removed and destroyed. Harvest potatoes early to avoid infection.
Keep plants well fed and remove excess leaves to allow a good air flow between plants.
Once established it is hard to treat. Spray with a protective copper based fungicide (Fungus Fighter Copper Fungicide).
Spray with sulphur or systemic fungicides as soon as symptoms appear, respray as per manufacturers instructions.
Note: Use registered fungicides with care.
Always read the manufacturers instructions and warnings before you begin and use as directed.
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Potato Tuber Moth (Pests)
Description: The moth is light brown to grey and around 7mm long, it is seldom seen because it is very small and is active at night. It is the larvae (caterpillar) of the moth that causes all the damage which eat through the leaves and stalks and tunnel into the tubers The larvae are pink to green and 2cms long with a dark brown head.
Affects: Potatoes, tomatoes and other members of the Solanaceae family
Solution: Remove infected leaves. Ensure soil is high in nutrients and banked up around the plant. Remove all weeds. Harvest early and make sure all potatoes are taken from the soil.
Derris Dust - active ingredient Rotenone is made from natural root extract (toxic only to fish)
Spray with Omethoate based insecticide like Folimat
Note: Many chemicals sold can be harmful to other insects as well as some animals and in some cases, humans.
Always read the manufacturers instructions and warnings before you begin and use as directed.
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Powdery Mildew (Disease)
Description:
This is caused by a variety of fungi, all have the same life cycle, cause similar problems and are treated in similar ways. Each fungi attacks a specific range of plants. Infection shows as a white powdery growth on leaves flowers and twigs. Leaves may turn yellow and drop. As with all fungi they prefer warm humid conditions.
Affects:
Pumpkin, squash, marrow, cucumber, roses, peas, turnip, strawberries, aster, poppy, zinnia, pansy, delphinium, roses, apple, begonias, hydrangeas and eucalyptus seedlings
Solution:
The best solution is to introduce fungus eating ladybirds (Illeis galbula) which are bright yellow and black. Otherwise remove and destroy all infected leaves and stems.
Space plants a sufficient distance apart to allow for good circulation of air.
Spray with sulphur or systemic fungicides as soon as symptoms appear, respray as per manufacturers instructions.
Note: Use registered fungicides with care. Always read the manufacturers instructions and warnings before you begin and use as directed.
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Rabbits (Feral) (Pests)
Description: In some areas feral rabbits are at plague proportions, yet in others its a rarity. In parts of Sydney it can be a big problem and your salad and brassicas will be their prime target as well as other juicy border plants.
Affects:
Solution: If you haven't got your garden fenced then the only option is bird netting (and a letter to the local council to organise humane culling)
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Red Scale or California Red Scale (Pests)
Description:
Red scale is a hard scale, so it doesn't produce honeydew and all its related problems. It does cause serious damage to the tree. The small reddish-brown round scale can be seen on the leaves and tend to be accompanied by yellowing of the area around the scale. It young trees the scale can cause serious damage and on occasions can lead to death.
The young nymphs (crawlers) are the only mobile stage and also the most susceptible. Once the nymph starts to feed it becomes stationery and builds a protective coating over its body.
Affects:
Citrus - leaves, fruits, twigs and branches. Can also affect
Solution:
Monitor the new growth and at the first sign of crawlers spray with Pest Oil. Check regularly during October and March.
It is possible to purchase Parasitic wasps to devour the insects. Aphytis are tiny yellow wasps they lay their eggs under the scale cover, on hatching the larvae feed on the red scale.
Small infestations can be removed by hand either rub the scale off leaves or smooth stems or brush vigorously with an old toothbrush to remove scale from older branches. Remove and destroy heavily infested branches.
NOTE: Many chemicals sold can be harmful to other insects as well as some animals and in some cases, humans. Always read the manufacturers instructions and warnings before you begin and use as directed.
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Root Knot - Nematodes (Pests)
Description: Root Knot is caused by microscopic nematode worms.
These tiny worms penetrate the roots and start feeding. Their saliva stimulates the plants defences leading to cell division in that part of the root and the formation of knobbly lumps on the roots called 'Galls'.
The galls interfere with the movement of water through the roots. The above ground parts of the plant show signs of water stress: slower growth, yellowing leaves and wilting especially in hot weather eventually leading to death of the plant.
Affects: Wide variety of plants including potatoes, tomatoes, carrots, hibiscus and roses.
Solution: Remove and destroy all infected plants.
Leave the area fallow for up 1 year (aim to starve the nematodes)
Add organic matter that will contain 'good' nematodes that will feed on the 'bad ones
Plant crops that are resistant to nematodes - Brassicas ( ie cabbage, cauliflower) onions and corn
Plant flowers that nematodes find toxic. Marigolds are one such plant however these are not toxic to all nematodes.
There are nematicides available but these are very toxic and not recommended for domestic use.
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Root Rot - phythophthora (Disease)
Description:
Is caused by the Phythophthora fungus that lives in moist soils.
This tends to be a problem of poorly drained and saturated soils. It is a problem seen in both indoor and outdoor plants. It is one of the biggest killers of indoor plants and caused by over-watering and insufficient drainage.
The fungus enters the roots via the root hairs and destroys the roots vascular tissue. The healthy creamy white roots become brown and brittle as they die. The plant is less able to take up water and develops signs of water stress: yellowing leaves, wilting, leaf drop and branch die-back. In hot conditions the plant may die quickly.
Affects:
A wide range of plants including strawberries, carnations, come cypress species and wide range of Eucalyptus and Oleanders.
Solution:
If the problem is pick up before the majority of roots have been affected the plant may be saved by improving the draining, avoiding over watering adding organic material to the soil and making sure that any mulch or weeds are kept away from the base of the trunk.
In many cases the plant cannot be saved and the only option is to remove and destroy the plant. If you are getting rid of an indoor plant make sure that you throw the soil with the plant.
When it is time to replace the plant choose an phytophthora resistant species.
For plants with a reasonably functioning root system then a systemic fungicide like Fongarid can be applied. The key being that the roots must be able to take up the fungicide.
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Rose Dieback or Canker (Disease)
Description: This is a fungal disease of the stems. The stem below the pruning cut turns brown and dies back to either a large bud, branch stem or in less resistant varieties to the base killing the whole plant.
Affects: Roses
Solution: The fungi enters the plant through pruning wounds or damage to the stem. It is important that clean sharp secateurs when pruning roses.
Remove infected stems to well below the dieback and to a branch node. Fertilise to encourage healthy growth.
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Rose Scale (Pests)
Description:
Rose scale can be seen on the older stems of roses. The female scale are small, round and white whilst the male scale are smaller more like desiccated coconut in appearance.
Over summer their population increases very quickly and it not treated, stems can soon become white with scale.
Rose scale is a sap sucking insect it takes goodness from the plant causing the plant to become stunted and stressed.
Affects:
Roses, members of the raspberry family
Solution:
It is important to control hard scales as their numbers can increase in number rapidly during the warmer months and stress the plant.
Spray the stems with Lime Sulphur during winter, this will cause the scale to dry out and die. During the warmer months spray with Pest Oil every 10-14 days, the aim is to kill the young 'Crawler' nymphs as they leave the protection of the parent scale and migrate to a new attachment site on the plant.
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Author: Bob Saunders.