Control PLANT DISEASES
in yard and garden

Mimeo BP-2-11

Fungicides for Shade Trees

Shade trees are an important part of
any home landscape plan--and the most per-
manent. It may take years before a tree
provides the shade and beauty desired by
the homeowner. Therefore, proper tree
care and control of tree diseases should
not be overlooked.
Shade trees are subject to a variety of
diseases which can disfigure, defoliate, or
even destroy. Oaks, elms, maples, syca-
mores, as well as evergreens like spruce,
pine, yew, and juniper are a few Hoosier
favorites suceptible to plant disease attack.
One of the best weapons against com-
mon tree diseases is use of fungicides.
These chemicals are not cure-alls nor are
they always necessary, but they can provide
effective control for highly-prized trees if
the right material is applied at the right
time.
In the following tables, diseases com-
mon to Indiana trees are briefly described
and control measures suggested. Those
planning to plant new trees may find it worth-
while to check over the list of disease-re-
sistant and disease-free shade and orna-
mental species. A condensed yearly spray
guide is also included for those desiring
maximum disease protection for their trees.

SHADE TREE FUNGICIDES
The fungicides in Table 1 are used to
control tree diseases caused by various
fungi. These chemicals will protect against,
not cure, established diseases. There-
fore, they must be applied before diseases
are established--correctly and at the ap-
propriate time. And they must be reapplied
during critical infections periods to protect
growing fruit, flowers, and leaves.

COMPATIBILITY WITH OTHER CHEMICALS
The organic fungicides, such as
zineb, ferbam, dichlone, Karathane and
Cyprex, may be safely combined in the
same sprayer with insecticides like mala-
thion, methoxychlor, parathion, DDT, lead
arsenate, Systox and DDD. Phenyl mer-
curies and liquid lime-sulfur are also com-
patible with most common insecticides.
Antibiotics such as streptomycin
are most effective when used alone, but
they can be safely combined with most in-
secticides except lindane, chlordane and
Genite (Ovex).

HOW MUCH AND HOW TO APPLY
Chemical control of shade tree
diseases is most effective when the material
is applied as high pressure sprays. (Dusts
are not too effective.) If the tree is not
over 10 feet high, application with a 3- to
5-gallon tank-type sprayer or a small 15-
to 20-gallon gasoline-powered garden spray-
er will probably do the job. However, com-
plete coverage of both upper and lower leaf

Cooperative Extension Service PURDUE UNIVERSITY Lafayette, Indiana
Department of Botany and Plant Pathology, Life Science Building