The fungicide tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, Toprose Fungus Control &Protect) has a recommendation for the control of leaf spots on ornamental plants.Additonally, the fungicides tebuconazole (Provanto Fungus Fighter Concentrate) and triticonazole (Fungus Clear Ultra) are labelled for the control of other diseases on ornamental plants. These fungicidesmay give some control of the disease on trees being grown as ornamental specimens, from which the fruit will not be consumed. The first formed spores (spring spores) infect young stems, causing distortion and the production of bright orange pustules. Spores from these pustulesin turn infect the leavesto produce dusty orange spores (summer spores) thatare spread by wind and initiate further infections. Infection is favoured by prolonged periods of leaf wetness. In late summer, the pustules producing summer spores switch over to producingthe dark, tough resting spores. These resting spores can survive the winter, on fallen leaves or often adhering to stems or trellises. If infections are persistently troublesome, it may bethat the cultivar concerned is unusually susceptible, so consider replacing it with a different one (but be aware of potential problems from replant diseaseif another rose is planted in exactly the same spot)

Spots appear on petals under wet conditions, which spread rapidly and cause the petals to collapse in a wet, slimy mess Similar non-chemical control measures can help to prevent infection by leaf spot fungi, downy mildew and grey mould,which are all 'wet weather' diseases (see the 'biology' section, below): Resistant cultivars are available for some plants. Resistant apple, pear and pyracantha cultivars are listed in the separate profiles on apple and pear scab and pyracantha scab Further information on the management of downy mildews, powdery mildews and grey mould can be found in the advice profiles on the links below: There are no fungicides available to amateur gardeners with activity against downy mildewor grey mould.

Fungicides for gardeners (Adobe Acrobat document outlining fungicides available to gardeners) Links Prolonged leaf wetness is not required for infection by p owdery mildew, but high humidity is, so providing good air circulation is still important. Avoid drought stress and the overuse of nitrogenous fertilisers. Chemical control Ensure that any leaves falling prematurely from an infected plant are collected up and disposed of (by burning, burial or consigning to the council green waste). Heavily-infected shoots could be trimmed off and disposed of in the same way. All Stewarts stores offer the option to reserve items, pay for them online, and collect them in store. You can see from a glance which stores have the item you are viewing by looking at this section:

Powdery mildew or leaf spots: leaf removal is not recommended as it would cause severe defoliation. Unless very severe, these infections should be tolerated Chooseless susceptible cultivars if downy mildew becomes a persistent problem. It is mainly a problem withbroad-leaved cultivarssuch as Veronica‘Midsummer Beauty’ and x ‘Franciscana Variegata’ but also occasionally present in some of the smaller-leavedspecies and cultivars,e.g . V. albicans, V. ‘Frozen Flame’ , V. rakiensis, V . ‘Youngii’ (syn. ‘Carl Teschner’) . Stemphyliumsp. causessmall, dark brown or purple spots on the leaves. The spots do not merge together, nor enlarge in size. The centre of the lesion can sometimesbecome pale in colour. The infected leaves shrivel prematurely and can either remain on the plant or drop off.

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The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner. Non-chemical control SB Plant Invigorator, Growing Success Fungus Stop, RHS Bug and Mildew Control, Ecofective Bug & Mildew Control and the Ecofective ‘Defender’ range contain a blend of surfactants and nutrients and can be used on any edible or ornamental plants, with no harvest interval. They have a physical mode of action and may be used against powdery mildews, as well as a range of pests such as whiteflies, aphids, spider mites, mealybugs, scale insects and psyllids. They are unlikely to be effective against leaf spots.

Fungicides are likely to need several applications during the growing season, particularly when spring and summer are wet. No fungicides are available to gardeners for use on olive trees from which the fruit will be harvested and consumed. Leaf spot: the leaf spot fungus produces water-dispersed spores from fruiting bodieson the infections. Asexual spores (conidia) of the g rey mouldfungus are always present in the air. They require leaf wetness or very high humidity to germinate and infect. Damaged or senescent plant parts are a very common way in which the fungus gains entry to the plant. The disease has a huge host range, and is active over a wide temperature range. Distorted leaves are often the first sign of infection, especially with the larger-leaved cultivars. A grey/mauve felt-like 'fungal' growth appears on the under-surface of the leaves, with diffuse purple-red or yellow patches developing on the corresponding upper surface.The fungicides tebuconazole (Provanto Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, ToproseFungus Control and Protect), and triticonazole (Fungus Clear Ultra) are labelled for the control of a number of other diseases on ornamental plants, and may give some control of olive scab on olive trees grown as ornamental plants only, although this is not claimed by the manufacturers.