Chapter 47

Sometimes the outdoor Tomato crop is attacked by _Phytophthora infestans_, the fungus responsible for the Potato Disease: Bordeaux mixture should be used to check it.

Directions for preparing the Bordeaux mixture are given on page 440.

Another useful preparation which checks many fungus diseases may be made by dissolving one ounce of potassium sulphide (liver of sulphur) in three or four gallons of water, to which should be added an ounce or two of soft soap. The last named greatly assists in the complete and uniform wetting of all parts of the foliage.

THE FUNGUS PESTS OF CERTAIN FLOWERS

Cineraria and Senecio Disease.—_Senecio pulcher_, soon after its introduction into England, was attacked, and in some gardens completely destroyed, by a fungus named _Puccinia glomerata_, or rather the _Uredo_ stage of this fungus with simple, not compound, spores. The fungus is well known, being closely allied to that which causes the rust or mildew of corn crops. It is very common on the wild species of Groundsel in England, being especially frequent and virulent on the Ragwort Groundsel, _Senecio Jacobea_, from August to October. The leaves of infected plants are covered with rust-coloured dusty pustules, the _Uredo_ condition of the fungus, and known in this stage as _Uredo senecionis_, sometimes termed _Trichobasis senecionis_. The fungus has a _Puccinia_ stage of growth very similar to that of the Hollyhock fungus, _Puccinia malvacearum_.