A small grey-black beetle often found wandering amongst plants at night.
Symptoms
One of the gardener's worst enemies - virtually undetectable until the plant wilts and begins to topple over. The beetle itself takes irregular chunks out of the edges of leaves and often hides in daylight at the bottom of pots and saucers. The main damage is caused by its creamy white grubs with brown heads, which hatch out from the many eggs a female can lay in its lifetime.
The eggs are laid amongst the roots of a plant and the grubs eat away at the tender white roots until the plant can no longer take in nourishment or maintain its stability. A slight touch can dislodge an affected plant completely.
Treatment
Most cases will be discovered in early spring when plants fail to thrive after a winter's rest. Re-potting in the autumn can often avoid the problem. Removing all the soil from affected roots, the comma-shaped grubs can be seen curled up in the nooks and crannies of the root ball. A knitting needle is useful to prise the grubs out and followed by a good rinse in a mild disinfectant solution the plant will usually be saved by re-potting. If too much root material has been destroyed it may be too late. In this case emergency cuttings should be taken or branches kept in water until new shoots appear for the purpose.
Prevention involves watering in a solution of Provado or similar proprietary remedy before over-wintering. This should kill the grubs in situ. It can be used at any time of year for general protection. It is also advisable to check hiding places for adult weevils in the daytime or even venture out with a torch at night to spot them actually on your plants.
Monday, 27 June 2011
Pests and Diseases - RUST
Rust is a fungus which is often peculiar to the plant it infects. e.g: fuchsia rust or geranium rust.
Symptoms
Plants show patches of rust-coloured powder on the underside of leaves. Often the upper surface is also discoloured in the same area. This may be the first sign of trouble.
Rust is highly contagious, scattering in a wide area around infected leaves. Spores carry in the air so it is wise to disturb the leaves as little as possible when dealing with an outbreak.
Treatment
Treatment with a fungicide in the early stages may be effective. All infected leaves should be collected and burnt or disposed of safely.
In the event of a more serious outbreak the whole plant may have to be destroyed. Wet weather seems to create the conditions in which rust thrives. However, good hygiene and fungicide treatment can usually save a plant to live a long and healthy life. Don't be too quick to bin those special varieties.
Symptoms
Plants show patches of rust-coloured powder on the underside of leaves. Often the upper surface is also discoloured in the same area. This may be the first sign of trouble.
Rust is highly contagious, scattering in a wide area around infected leaves. Spores carry in the air so it is wise to disturb the leaves as little as possible when dealing with an outbreak.
Treatment
Treatment with a fungicide in the early stages may be effective. All infected leaves should be collected and burnt or disposed of safely.
In the event of a more serious outbreak the whole plant may have to be destroyed. Wet weather seems to create the conditions in which rust thrives. However, good hygiene and fungicide treatment can usually save a plant to live a long and healthy life. Don't be too quick to bin those special varieties.
Pests and Diseases - ROOT ROT
Often a result of over-watering
Symptoms
The plant fails to thrive. Leaves become limp and yellow and eventually fall off. On lifting the root ball from the pot it is obviously water-logged and the roots are a dark brown colour. If they are already quite rotten they may fall off at a touch.
Treatment
A plant which has reached this sorry state may have lost too many roots to recover. It may be possible to save it by using the same measures as for over-watering. It will be necessary to produce enough healthy white roots to sustain the plant before it is likely to recover.
Root rot is the result of poor greenhouse management and can often be due to cramped roots and the need for re-potting in a larger size pot, but over-watering is the main culprit. Never leave a fuchsia standing in a saucer of water after it has soaked up its immediate requirements.
Symptoms
The plant fails to thrive. Leaves become limp and yellow and eventually fall off. On lifting the root ball from the pot it is obviously water-logged and the roots are a dark brown colour. If they are already quite rotten they may fall off at a touch.
Treatment
A plant which has reached this sorry state may have lost too many roots to recover. It may be possible to save it by using the same measures as for over-watering. It will be necessary to produce enough healthy white roots to sustain the plant before it is likely to recover.
Root rot is the result of poor greenhouse management and can often be due to cramped roots and the need for re-potting in a larger size pot, but over-watering is the main culprit. Never leave a fuchsia standing in a saucer of water after it has soaked up its immediate requirements.
Pests and Diseases - RED SPIDER MITE
Red spider mite often occur during a long spell of hot weather.
Symptoms
It is difficult to detect red spider mite in the early stages. Rarely seen in early spring it makes an appearance as plants mature and the weather warms up.
These pests are not spiders but probably get their name from the webs that appear in the later stages of an infestation. The mites are almost invisible to the naked eye but quite obvious under a magnifying glass as tiny whitish flecks moving around under the leaves and in the web-like structures. The underside of the fuchsia leaves take on a bronzed look. As time goes on the leaves turn brown and shrivel up, eventually falling off the plant which can die if the infestation is sufficiently advanced before it is noticed.
Treatment
This problem is best caught early if the plants are to be saved. In hot weather fuchsias should all be outside as red spider mite spreads like wildfire in the greenhouse. Regular hygiene routines and spraying with a good insecticide will go a long way towards keeping the mite under control but it is notoriously difficult to find a totally effective spray. Examination of the underside of leaves will reveal the bronze effect before the damage is too far advanced for treatment. Spray lightly to keep plants moist.
At the end of a long hot summer many plants will be showing signs of red spider mite infestation but most will survive.
Destroy badly infected plants and isolate the rest. These should be defoliated (leaves stripped) and cut back. Winter is a good remedy as the mite is unlikely to survive cold weather- try again next year!
Symptoms
It is difficult to detect red spider mite in the early stages. Rarely seen in early spring it makes an appearance as plants mature and the weather warms up.
These pests are not spiders but probably get their name from the webs that appear in the later stages of an infestation. The mites are almost invisible to the naked eye but quite obvious under a magnifying glass as tiny whitish flecks moving around under the leaves and in the web-like structures. The underside of the fuchsia leaves take on a bronzed look. As time goes on the leaves turn brown and shrivel up, eventually falling off the plant which can die if the infestation is sufficiently advanced before it is noticed.
Treatment
This problem is best caught early if the plants are to be saved. In hot weather fuchsias should all be outside as red spider mite spreads like wildfire in the greenhouse. Regular hygiene routines and spraying with a good insecticide will go a long way towards keeping the mite under control but it is notoriously difficult to find a totally effective spray. Examination of the underside of leaves will reveal the bronze effect before the damage is too far advanced for treatment. Spray lightly to keep plants moist.
At the end of a long hot summer many plants will be showing signs of red spider mite infestation but most will survive.
Destroy badly infected plants and isolate the rest. These should be defoliated (leaves stripped) and cut back. Winter is a good remedy as the mite is unlikely to survive cold weather- try again next year!
Pests and Diseases - OVER-WATERING
One of the commonest causes of plant death
Symptoms
The plant wilts and looks as though it actually needs water. The pot feels heavy and may drip if lifted up, especially if it has been standing in a saucer which has stagnant water in it.
Treatment
.Watering the plant at this stage may be fatal and it may never recover. Emergency measures include baring the root ball and draining on newspaper until it becomes less wet. Squeezing the root ball carefully can hasten the drying-out process. The plant may then be re-potted using a fairly dry compost. If things have not reached the point of no return (See root rot ) this may save your plant. Fuchsias should never be left standing in saucers of water. When watering any surplus water should be drained away after half an hour. The weight of pots can be a good indication of dryness. With clay pots an experienced grower can tell by the sound of the pot when tapped lightly. The debate on watering from the top or bottom of the plant has yet to be resolved.
Symptoms
The plant wilts and looks as though it actually needs water. The pot feels heavy and may drip if lifted up, especially if it has been standing in a saucer which has stagnant water in it.
Treatment
.Watering the plant at this stage may be fatal and it may never recover. Emergency measures include baring the root ball and draining on newspaper until it becomes less wet. Squeezing the root ball carefully can hasten the drying-out process. The plant may then be re-potted using a fairly dry compost. If things have not reached the point of no return (See root rot ) this may save your plant. Fuchsias should never be left standing in saucers of water. When watering any surplus water should be drained away after half an hour. The weight of pots can be a good indication of dryness. With clay pots an experienced grower can tell by the sound of the pot when tapped lightly. The debate on watering from the top or bottom of the plant has yet to be resolved.
Pests and Diseases - GREENFLY/APHIDS
Greenfly / aphids thrive on the young growing tips of plants.
Symptoms
Greenfly or aphids are tiny insects that can be any shade of green, brown, red or even black. They live in colonies and can be found in either a winged or a wingless form.
First signs of an infestation are often seen in distorted leaf development, especially in the young shoots. Later there may be a sticky secretion on leaf surfaces dropped by aphids from leaves above. This in turn can become black as sooty mould takes over. One or all of these signs can indicate that these pests have taken up residence on your plant. Aphids particularly tend to favour the underside of leaves at compost level and are difficult to spot. Aphid damage causes limp, yellowing leaves which eventually drop off.
Treatment
Spraying with a proprietary insecticide as per the manufacturer's instructions. Regular inspection of growing tips and underneath lowest leaves will pay dividends. Remove all badly damaged or infested leaves. Regular pinching out in the early stages of growth limits problems of leaf distortion.
Symptoms
Greenfly or aphids are tiny insects that can be any shade of green, brown, red or even black. They live in colonies and can be found in either a winged or a wingless form.
First signs of an infestation are often seen in distorted leaf development, especially in the young shoots. Later there may be a sticky secretion on leaf surfaces dropped by aphids from leaves above. This in turn can become black as sooty mould takes over. One or all of these signs can indicate that these pests have taken up residence on your plant. Aphids particularly tend to favour the underside of leaves at compost level and are difficult to spot. Aphid damage causes limp, yellowing leaves which eventually drop off.
Treatment
Spraying with a proprietary insecticide as per the manufacturer's instructions. Regular inspection of growing tips and underneath lowest leaves will pay dividends. Remove all badly damaged or infested leaves. Regular pinching out in the early stages of growth limits problems of leaf distortion.
Pests and Diseases - CAPSID BUGS AND THRIPS
These pests are very difficult to spot but their presence is indicated by extensive damage and distortion of young growing tips.
Symptoms
Like greenfly and aphid damage the growing tips of plants are most affected. If flowers are scarce in early summer this is because the pests have eaten the new buds. Remaining leaves may be completely distorted when they appear or have holes in them. Leaf ends can be discoloured with black or brown speckles.
Treatment
This is not an easy condition to recognise in time to save the season's flowers. Regular inspection and spraying is recommended. It may be possible to remove all terminal buds and let the plant start again when the thrip/capsid bug infestation begins to ease in late summer. A second crop of flowers is less likely to be affected.
Thrips are very small creatures unlikely to be noticed but the capsid bug is quite conspicuous although very quick to disappear. Pinch an affected branch some way below the tip and watch carefully. A bright green beetle like a large aphid can often be seen scuttling down the stem to where you have cut off its retreat. Normally it would have disappeared quickly into the compost surface unnoticed. These are solitary creatures as a rule.
Once again this is a case where regular inspection and good hygiene pay off. It is probably most troublesome with plants outdoors.
Symptoms
Like greenfly and aphid damage the growing tips of plants are most affected. If flowers are scarce in early summer this is because the pests have eaten the new buds. Remaining leaves may be completely distorted when they appear or have holes in them. Leaf ends can be discoloured with black or brown speckles.
Treatment
This is not an easy condition to recognise in time to save the season's flowers. Regular inspection and spraying is recommended. It may be possible to remove all terminal buds and let the plant start again when the thrip/capsid bug infestation begins to ease in late summer. A second crop of flowers is less likely to be affected.
Thrips are very small creatures unlikely to be noticed but the capsid bug is quite conspicuous although very quick to disappear. Pinch an affected branch some way below the tip and watch carefully. A bright green beetle like a large aphid can often be seen scuttling down the stem to where you have cut off its retreat. Normally it would have disappeared quickly into the compost surface unnoticed. These are solitary creatures as a rule.
Once again this is a case where regular inspection and good hygiene pay off. It is probably most troublesome with plants outdoors.
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