Dealing With Common Pests and Diseases of Garden Plants
Many plants are susceptible to various ailments. Often the natural balance of the garden i.e. natural predators and of course good cultivation, are enough to maintain control. However occasionally the gardener needs to intervene.
Verbascum
These are attacked by mullein moth caterpillars, any insecticide will effect control, or pick them off as you spot them.
Roses, Hollyhock, Campanula persicifolia (peach leaved bellflower) and all other types of Campanula
May get Rust, Blackspot, Aphids. Use Rose Clear or Tumble Blight, spray routinely, perhaps when you spray the roses. This is a problem especially during warm damp weather
Hardy geraniums, Aster, Monarda, Hebe and other members of the scrophulariaceae such as Foxgloves and Penstemons.
These can suffer from powdery mildew. Give plants plenty of room to allow good air circulation. Water in the morning so foliage is dry by nightfall. Almost any fungicide will give control.
Leaf Spot Diseases
Especially prone are herbaceous perennials. Rose clear or Tumble Blight. Remember to follow exactly the dosages and instructions on the packets and bottles. Occasionally alternate with sprays containing different ingredients.
Slugs
There are many alternatives you could try them all, but its a battle most gardeners have. Beer is often used in small containers or bottles buried near plants. Crushed eggshells or sharp sand is sometimes placed around the plants, but as soon as the rain comes it gets washed in or away.
The best natural predators are frogs and hedgehogs and encouraging them to flourish by digging a pond can be very effective but ponds and associated wildlife can have their own problems. As many amphibian species are under threat from global warming encouraging them into your garden is also great for our natural ecosystem and their prevalence is a sign of ecosystem health.
Or
Tie a length of string to a small stone used to prop up a larger stone. Lie in wait, patience may be required. When a slug comes by you need only pull the string hard, the propped up flat stone will fall despatching the slug!!
Good Luck