BlueWisteria.co.uk for down to earth gardening information.

Black spot is a fungus disease that primarily infects rose bushes, although several other plants can be infected. As its name suggests, leaves of infected plants develop numerous black spots on the leaves. This causes the foliage to yellow and die prematurely, and entire stems may die back until eventually the plant itself may die.

Cures are difficult as the spores of the fungi are spread over the soil ready to infect the plants again the following season.

Gather up and dispose of all dead or infected leaves and spray the bushes with fungicide early next spring as a preventitive measure.

Classic symptoms of chlorosis is the presence of pale yellowing leaves with dark green veins, giving rise to the common name of green vein disease. This ailment is not strictly a disease in the true sense, but a dificiency of vital minerals. This prevents the plant from taking in the fertilizer elements required for normal growth.

Hydrangeas are very prone to this problem and luckily there is a simple remedy: put the minerals back into the soil.

Watering the soil around the root area with sequestered iron, often sold as 'Sequestrene', will cure the problem.

Preventative measures must be taken as early in the growing season as possible, as old sickly leaves will not regain their proper colours.

Although there are a many different species of snail, the common brown garden snail is the one most likely to be a problem in the garden. Snails are most active during warm wet spells but are a persistant problem throughout the summer.

Leaves and emerging shoots are most at risk from this pest and damage can vary from a few holes in leaves, to entire plants consumed overnight.

Remedies: Slug pellets still remain the only effective control for snails, and if used in moderation should not do any harm to wildlife or domestic pets. Keep gardens as clean as possible to deny them a safe haven.

Slugs are 'snails without shells' and come in many different colours and sizes. They all eat the gardener's flowers from top to bottom, flowers, leaves, stems and even roots and fruit.

The one good thing about some slugs is the fact that they eat each other, and the dead snails you stood on yesterday.

Control is much the same as for snails, with slug pellets being the primary method of control. Keeping toads in the garden will assist in keeping the numbers reduced but it is an ongoing battle with no end.

Mildew is a fungus disease that infects leaves of plants. Infected foliage develops a covering of a white powdery substance, with the leaves eventually curling up and dieing early. This disease tends to remain at a constant background level ready to flare up usually during damp spells.

It is important to gather up and destroy all infected foliage otherwise the spores will spread the disease further.

Spray leaves with fungicide at the first signs of infection and repeat as neccessary. A relatively new method widely muted is to spray the leaves with diluted milk but I have not had the time to test this.

This is such a lovely flower it is a real pity it refuses to grow in nice straight rows. Quick to establish in the worst possible growing conditions it never needs any water, seems resistant to all common garden pests and flowers continually.

This weed has a deep tap-root making hand-weeding pretty well impossible. A fork or daisy grubber can help to remove stubborn plants from the borders but usually the root breaks. The broken root will re-shoot and be flowering within a week or so. Any that refuse to leave will require spraying with a contact weed-killer. As always, follow the instructions issued by the manufacturer.

Dandelions are at their worst when they get established in the lawn. Here they not only look untidy but spoil the grass. The rosette of leaves spread flat on top of the grass and press themselves down below the level of the lawnmower where they are safe, suffocating the turf in the process. Good lawns don't have dandelions though as the annual lawn treatments should eliminate all traces of them.

Dandelions are useful

It may come as a surprise to you to discover that the dandelion is a very useful plant with many uses. All parts of the plant are edible so I will start at the bottom and work upwards.

Roots.

If starvation threatens, these can be cooked like any other root vegetable though a bit fiddly. However, when roasted, ground and percolated they will produce a decent cup of "coffee".

Leaves.

The leaves can be used raw like any other salad green and provide an alterative to a boring lettuce. Presumably they could be cooked as well.

Flowers

The flowers or roots are traditionally collected and turned into wine. Sorry, but I don't have any suitable recepies. I prefer the root wines such as parsnip or potato.

Seeds.

As every child knows, if you count how many times you have to puff before all the seeds blow away it will tell you the time.

The blobs of froth covering many plants in summer look unsightly and are caused by an overgrown aphid-like creature that spends most of its life drinking sap and blowing bubbles. Due to the relatively low numbers of froghoppers present at any one time, the damage is usually slight and is more of a visual nuisance.

If the unsightly spit is too much to bear, the only solution is to spray with systemic insecticide.

This pest has made a recovery from almost extinct to being a serious problem within the last couple of decades and is now widespread accross most parts of Gt. Britain.

The adult beetle is a reddish-orange in colour and is easily seen lurking amongst the lily foliage. While the devastation done by this pest is largely the work of the grubs, the adult beetles eat small notches from the leaf edges.

Beetles make their first appearance between mid April and June depending on weather and location, and if you value your lilies you must act quickly. Spraying the foliage of lilies with a good systemic fungicide should see them off, but repeat sprays will be required.

The alternative organicly sound method is to make a thorough check of all your lilies every day to pick off and dispatch the adults and check under the leaves for clusters of orange eggs. Once the larve emerge, things start to get messy as the grubs conseal themselves in a ball of their own excrement.

Within a few days of the adult beetles arriving at your lily plants, clusters of eggs are laid on the undersides of the foliage. If left to hatch, orange grubs emerge and set about defoliating your prize lilies.

As they grow, these grubs cover themselves in a ball of their own excrement such that the plants look like they are covered with small balls of dung that slowly move over the leaves, stripping them as they go. Once the warmer weather of summer sets in, the lilies will receive daily visits from more beetles, and plants will have eggs, grubs and adult beetles present at the same time. Successive generations will reduce lily plants to bare stems in a matter of weeks, then they eat the stems.

Wiping these grubs off your lilies by hand is not a pleasant occupation but is pracical if you only have a small number of plants. Spraying with a systemic insecticide will produce far better results as this will also kill off the adults as they nibble at the leaf edges.

Green aphids can be an absolute scourge for the gardener in early summer when these pests multiply at an alarming rate in the absence of natural predators. They congregate on young plant shoots near the tips and suck the very life out of the plants. In the process, they also secrete a sticky sugary substance on the lower leaves that in turn becomes a breeding ground for mould and other fungi.

As the colonies develop, predator insects move in and eventually reduce their numbers to a manageable level but often severe damage has been done. Populations can blow in or flare up at any time during the growing season calling for constant vigilance.

When populations suddenly build up in large numbers, the insect spray gun is your only option.

Often called the skeletonizer due to the larves habit of eating all the leaf except the prominent ribs, this small caterpillar-like larve is well camouflaged and difficult to spot. The adult sawfly is noticable for its bright yellow abdomen, but causes no harm to the plants.

The larve have voracious appetites and rapidly denude rose bushes of their foliage. There is usually several generations following in quick succession but the damage done is usually more of an annoyance than significant.

The best treatment is to wait until the flush of flowers is over, then prune fairly hard removing all the larve in the process. Insecticide sprays will also rid the bushes of their unwelcome hosts, but may kill the beneficial predator insects as well.

Vine weevil grubs are a hidden menace tending to lurk in the loose compost of flower containers. Their presence usually goes unnoticed until you investigate why a plant is not growing too well and it comes away from the compost without any roots.

Close examination of the immediate area will reveal dozens of these small white maggots with orange head. These are the larve of the vine weevil, a small dark coloured beetle-like creature that also tends to go unseen due to its nocturnal habits.

Although these grubs tend to infect bedding plants and small 'rosette' type plants with soft roots, they do attack tougher looking woody plants, espesially when growing in containers. Fuchsias are a particular favourite.

The only reliable treatment for these weevil grubs is watering the soil with a systemic insecticide called Imidaciprid usually sold under the trade name of Provado.

This treatment must be applied early in the growing cycle of the grub otherwise you will not save the plants.