BOTRYTIS (GREY MOULD)
Strawberry affected by botrytis or grey mould
Grey mould, caused by the fungus Botrytis cinerea, is a very common disease, causing a growth of fuzzy grey mould. It infects many plants, especially those grown where conditions are so humid.
No fungicides are approved for use against grey mould by gardeners. Products containing plant and fish oil blends (Vitax Organic 2 in 1) may be used, but are not recommended by the manufacturers for grey mould control and are unlikely to have much impact. Use of other fungicides to control other disease problems may give some incidental control of grey mould, but this is not guaranteed by the manufacturers.
Strawberry affected by powdery mildew
Powdery mildew is a fungal disease of the foliage, stems and occasionally flowers and fruit where a superficial fungal growth covers the surface of the plant.
Most powdery mildew fungi have a host range restricted to a relatively few, related plants, but these can include wild relatives which can be sources of infection, e.g. wild crab apples may be sources of infection for apple orchards.
Seed producers sometimes offer powdery mildew-resistant cultivars of both vegetables and ornamental plants, check catalogs for details.
Edibles and ornamentals: Myclobutanil (Bayer Garden Systhane Fungus Fighter concentrate) can be used on ornamentals, apples, pears, gooseberries and blackcurrants.
Ornamentals only: tebuconazole (Bayer Garden Multirose Concentrate 2) and triticonazole (Scotts Fungus Clear Ultra) can be used on ornamentals. Some formulations of myclobutanil, tebuconazole and triticonazole contain insecticides to control pests. Avoid these unless an insect pest problem is specifically identified.
Red spider mites
Glasshouse red spider mite is one of the most troublesome pests of greenhouse plants, houseplants. It can also attack garden plants in the summer. It is a sap-sucking mite that attacks the foliage of plants, causing a mottled appearance, and in severe cases, leaf loss and even plant death.SYMPTOMS
Glasshouse red spider mite can be difficult to control as it breeds rapidly in warm conditions and some strains of the mite are resistant to some pesticides. Biological control is a viable alternative to using pesticides, it can give good control and as it avoids resistance problems and the risk of spray damage to plants.
As the predator is susceptible to pesticides, biological control cannot be used in conjunction with most chemical controls. The exceptions are those with very short persistence, such as plant oils or extracts (e.g. Vitax Organic 2 in 1 Pest and Disease Control, Bug Clear for Fruit & Veg) or fatty acids (e.g. Bayer Organic Pest Free, Doff Greenfly and Blackfly Killer, Bayer Natria Bug Control) or urea/mineral lattice (SB Plant Invigorator), which can be used to keep mite numbers down before it is time to introduce the predator.
Note that Phytoseiulus persimilis will not control other species of red spider mite, such as fruit tree red spider mite, citrus red spider mite, box red spider mite and conifer red spider mite.
Phytoseiulus and compatible biological controls for most other greenhouse pests can be obtained by mail order from specialist suppliers.
Fungal leaf spot
Strawberry black eye
Strawberry seed beetle