l upward and
the plant dies without wilting. The nature and cause of this disease is
as yet unknown. It appears to be worst on new land. Experiments that
have been made indicate that in older cultivated fields thorough
preparation of the soil, manuring and cultivation, combined with care in
transplanting to avoid injuring the roots and checking growth, will
greatly restrict the spread of this blight.

DISEASES CAUSED BY PARASITES

There are several fungous parasites of tomatoes, which, for the readers
convenience, may be briefly mentioned and the treatment of all discussed
together. The first three are indeed somewhat difficult to tell apart
without a microscope, as they produce a similar effect on the leaves and
all yield to the same treatment--thorough spraying with Bordeaux
mixture.

=Leaf spot= (_Septoria lycopersici_ Speg.) has been widely prevalent and
injurious during recent years. It produces small, roundish dark-brown
spots on leaves and stems. The lower leaves are attacked first and
gradually curl up, die and fall off. The vitality of the plant is
reduced and it is only kept alive by the young leaves formed at the
top.

The fungus that causes early blight of potatoes (_Alternaria solani_ (E.
& M.) J. & G.) occurs on tomatoes also, sometimes doing much injury. The
spots formed are at first small and black, later enlarging and
exhibiting fine concentric rings.

A somewhat similar leaf-blight results from a species of
_Cylindrosporium_, and other fungi may occur on diseased leaves.

=Leaf mold= (_Cladosporium fulvum_ Cke.) is quite distinct from the
foregoing in appearance. It does not cause such distinct spots but
occurs in greenish brown, velvety patches of irregular outline on the
under side of the leaves. The lower leaves are first attacked, and as
the disease progresses they turn yellow and drop off. This is the
principal fungous enemy of greenhouse tomatoes, but also does injury in
gardens, particularly in Florida and the Gulf region. It is readily
controlled by spraying. In the greenhouse care should be taken to
ventilate well, without, however, allowing cold drafts to strike the
plants.

=Downy mildew= (_Phytopthora infestans_ DeBy.), the cause of the late
blight of potatoes, will attack tomatoes during cool and very moist
weather, which greatly favors its development. Such outbreaks sometimes
occur to a limited extent in New England and serious losses are reported
on the winter crop in southe