Garden Pests and Diseases of Perennials, Annuals and Biennials

Garden Pests and Diseases of Perennials, Annuals and Biennials

slugs - garden pests and diseases Perennials, annuals and biennials are, of course, subject to attack by plant pests and diseases, but not to anything like the extent of some other ornamental plants. So far as I am concerned, at any rate, that is one of their most important virtues.

I would repeat my advice, though, that good garden hygiene is just as important with these plants as with others more prone to trouble in this respect. Provide good growing conditions and always clear away any dead plant material and other debris without delay.

With annuals and biennials, the most tricky time is bound to be when the plants are at the seedling stage. Under glass, in the case of half-hardy annuals, it is damping off which causes losses. This may be countered by careful watering and good ventilation as well as by treating the seed with thiram or captan dust before sowing, or by watering the seedlings with Cheshunt Compound when the trouble is noticed.

Outdoors, young seedlings are prone to attack by birds and the gardener now has an additional string to his bow in a bird repellant chemical named Morkit, which is applied as a spray. The traditional black cotton barrier made by weaving the cotton between closely placed sticks gives a good measure of success and so, to a limited extent, do the flapping scarers which glitter and tinkle — but with birds, as we all know, familiarity too often breeds contempt. If earwigs are damaging seedlings, a DDT or sac spray will bring relief, and the same chemicals will control woodlice which can also do considerable damage to seedlings at this early stage. Leatherjackets, too, can be troublesome with young plants and the way to avoid trouble from this quarter is to fork DDT or BHC dust into the soil.

Slugs can be a serious annoyance and these can be combated by placing a mixture of metaldehyde and bran or slug pellets around the plants being attacked. Aphis damage on perennials or annuals can be brought under control with gamma-BHC (lindane), menazon, malathion, derris and pyrethrum sprays. Dinocap fungicide sprays or dusting with flowers of sulphur are correctives for mildew attacks.

Aster wilt can be a trouble with annual asters and where this is the case it is advisable to grow early, wilt-resistant strains. Michaelmas daisies are also prone to attack by wilt and the only answer in this case is to be ruthless and destroy by burning all affected plants. After this, move the unaffected plants to a fresh site and leave the old site free of these flowers for several years.

Antirrhinums and hollyhocks are attacked by their own strains of rust disease. With antirrhinums, if this disease has given trouble, you should grow rust-resistant varieties. Destroy infected plants and as a preventive measure spray frequently with Bordeaux Mixture.

02. December 2010 by Dave Pinkney
Categories: Annuals, Biennials, Garden Management, Perennials, Pests and Diseases | Tags: , , | Comments Off on Garden Pests and Diseases of Perennials, Annuals and Biennials


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