==Pea Disease.==—­Although garden Peas often suffer badly from the attacks of =Peronospora viciae=, which is the cause of Pea Mould, yet the most deadly foe to Peas, especially late Peas, is a fungus of a totally different character.  To such an extent does the Pea Blight sometimes devastate the later Peas, particularly in dry summers, that the whole crop is in some gardens completely annihilated.  The name of the fungus of the Pea Blight or Mildew is =Erysiphe Martii=.  Its attack is often made suddenly; the leaves then lose their natural green colour, and become yellowish and densely coated with a fine white bloom; this bloom becomes at length dusted over with innumerable minute black bodies, which look, under a lens, like tiny spiders’-eggs in the web.  These little black bodies are filled with extremely small transparent vessels, and each vessel contains from four to eight spores or seeds.  Our illustration shows this =Erysiphe= enlarged one hundred diameters, with two of the vessels containing the spores removed from the globular spots and further enlarged.  The only safe way of dealing with infested Pea plants is to burn them.  Many other species of fungi belonging to the same genus attack fruit trees, vegetables, and garden flowers.  It is, however, unnecessary to illustrate them, as they more or less resemble the fungus of Pea Blight.  They all arise from an =Oidium= condition, similar to the =Oidium= or Mildew of the Vine, and it is in this condition alone, as in the case of the Vine, that they can be reached by any fungicide.

[Illustration:  X.100.  Fungus of pea mildew =Erysiphe Martii=]

==Tomato Diseases.==—­The Tomato, like its near relative, the Potato, is subject to a number of destructive diseases which spread rapidly if allowed to become established.  The most serious of these epidemics are found among crops cultivated under glass, where the forcing treatment which they often receive, and the soil and atmospheric conditions, render the plants abnormally susceptible to the attacks of fungi and insect pests.  Perhaps the most virulent forms of disease with which the Tomato-grower is troubled arise from the attacks of parasitic fungi and bacteria, among which the following are most frequently met with:—­

Sleepy disease, or Tomato wilt.—­In its outward symptoms and effects this disease somewhat resembles an attack of Root-knot Eelworm, but the swellings are absent from the root.  The plants for a time appear quite vigorous and healthy, but when full-grown they suddenly wilt and die within a few days.  The malady is caused by the fungus =Fusarium lycopersici=, which first invades the roots and ultimately eats its way through the substance of the collar or stem near the surface of the soil, in consequence of which the supply of water taken up by the roots is cut off from the leaves above ground and the plant collapses.  There is no remedy for the Sleepy Disease of Tomato, and plants which bear evidence of infection should be carefully dug up and burned.