When this style of arbor is used, the laths in overhead screens should not be more than three fourths of an inch apart, while the laths in panels around the garden should not be closer than two inches ; and the panels should be arranged so that they may be taken down in wet weather to allow the air to circulate freely, thus guarding against fengi and blight diseases affecting the plant. For t .p shade, the laths may be woven with galvanized w;re with a common fence-weaving machine, and will be found cheap and practicable. The writer has used this style of shading to a considerable extent for the past several years, and recommends it as being superior to other styles.
With complicated arbors, sometimes the drip is very injurious to the plants during heavy storms, and with this style of shading this difficulty is overcome almost entirely.
Enemies.
111/1.—The older ginseng plants are subject to a wilt-disease, from a fungus belonging to the genus Acrostalagmus. The leaves lose their turgidity and droop down against the stalk, which retains its upright position. The remedy is to dry the affected roots and to remove the soil from the infected beds, and to grow only vigorous roots for seed, which are more resistant.
The seedlings are also subject to wilt from vari ous causes. Sometimes the lower end is attacked by rot,—"end rot," as it has been called,—causing the root to shrivel and the leaves and stalk to wilt. The disease seems to be associated with improper moisture conditions, and ventilation and drainage are recommended in its control.
Millipedes frequently cause the seedling to wilt and die, by eating the roots and parts of the stem underground. The millipedes are trapped by laying boards on the surface of the ground, under which they gather. It is also suggested that they may be destroyed by scattering pieces of potato poisoned with arsenic, as they attack potatoes readily.
Alternaria blight is one of the worst enemies of the ginseng-grower. It manifests itself by a spot ting of the leaves. In the morning the spots look as though they had resulted from drops of scalding water, the diseased leaf-tissue being dark green and watery. When the diseased parts have become dried by the sun, the spots are yellowish and papery, the centers becoming brittle and easily broken out when handled. The leaves soon hang limp and dead from the stalks. Moist or rainy weather with high temperature seems to be most favorable to the rapid development of the disease. The disease may be prevented by a thorough application of Bordeaux mixture. The most certain method is to spray the
ground thoroughly with a strong solution of copper sulfate (two pounds copper sulfate, ten to fifteen gallons water), before the plants come up. As soon as the plants begin to appear, spray thoroughly with Bordeaux mixture. As the plants come up unevenly, it may be necessary to spray daily till all are up, after which thorough spraying every ten days or two weeks until the seed-heads begin to fill, will be sufficient. When the seed-heads are filling, they should be sprayed once or twice to protect them from the form of the disease known as blast.
Sqft rot of the roots is indicated by premature coloring of the foliage. The leaflets become bronze and then show a reddish coloration, followed by the wilting and death of the top. The roots rot, and become sticky, mushy and ill-smelling. This disease is destructive only in wet soils. Normally it is harm less, becoming parasitic on the roots only when their vitality is reduced by excessive moisture. The only remedy is thorough drainage.
Rot of stems and roots causes the stem to fall over from the weakening at its base, while the roots became soft and pulpy. The disease may be recog nized by the large black knots on the base of the stem or on the roots. Thorough ventilation and careful drainage are recommended.
Nematode root-galls.—The nematode worm attacks ginseng plants, especially those in gardens near woodlots. The largest knots seem to be formed on the main roots. The galls may reach a large size, and rapidly rob the plant of its vitality and reduce the value of the roots. The most effective remedy is to remove the garden to an unaffected place, and to be careful not to transfer any of the worms or eggs from the old garden. Seeds or unaffected roots should be used to start the new garden. Freezing and drying of the ground are both destruc tive to the worms. If the soil can be steam-steril ized, the worms and eggs will both be killed.
Snails eat the foliage and stems of young plants. A good method of extermination is to trap with slices of turnip or lettuce leaves. These may be placed about the garden and turned over from time to time, and the snails killed. With the aid of a lan tern they may be gathered at night from the foli age. Carbon bisulfid has been used with good ef fect, especially by applying along the boards, which afford an excellent hiding place for the snails. Care must be exercised not to have the carbon bi sulfid very strong. Air-slaked lime applied to the soil is said to give good results.