108 
F. & F. NURSERIES 
plants in any of the summer contact sprays diluted with water as 
recommended on the container. Be careful to wet the lower sur¬ 
face of the leaves. It is often advisable to give a second treat¬ 
ment in 5 or 6 days. 
PLANT BUGS, such as leaf hoppers, tarnished plant bugs, 
“white fly,” thrips, etc. All are sucking insects and they are 
more active than plant lice, therefore, much more difficult to wet 
all the insects with the spray material. Use summer contact 
sprays as recommended on the container or at strength slightly 
stronger than recommended for plant lice. Use considerable volume 
of spray where possible and wet lower surface of leaves. It is 
often necessary to give 3 or 4 treatments at weekly intervals. 
Nicotine or pyrethrum dusts are very good where plants are 
crowded or close together. 
MEALY BUGS. These are sucking insects covered with a 
white, powdery or woolly, wax-like material. The eggs are pink¬ 
ish, small, laid in masses of 100 or more and covered with the 
white, woolly, wax-like material. Both the insects and egg masses 
are difficult to wet with the spray material. Sprays containing 
nicotine are usually better for mealy bugs than those containing 
pyrethrum or rotenone. Sprays containing summer oil or wetting 
agents with oil are more effective than soap or other common 
wetting materials. Spray with considerable force and where pos¬ 
sible repeat the applications at 3 or 4 day intervals until the 
infestation is cleaned up. Large masses of mealy bugs or egg 
masses that are hard to wet may be painted with a solution of 
the spray material 4 to 6 times as strong as recommended for 
control of plant lice. After a few minutes or when these painted 
places have been wet thru syringe with clean water and spray 
with the regular strength recommended for mealy bugs. 
SCALE INSECTS. Two types are commonly found on orna¬ 
mental plants. One type is called armored scales because the 
body is covered with a round or oval, flat, wax-like scale, usually 
not more than % inch in diameter. The second type is called 
soft scales, because they have no protecting waxy scale, or they 
are sometimes called lecanium scales because of their shape. They 
are usually oval in outline, flat to hemispherical in shape and 
from % to % inch in greatest diameter. Both types are difficult 
to control with summer sprays after they become half grown or 
more. Regular spraying at about 10-day intervals with a summer 
contact spray about twice as strong as recommended for control 
of plant lice will kill the young insects and clean up an infesta¬ 
tion. Contact sprays containing summer oils are more effective 
against scale insects than those containing soap as the wetting 
agent. On hardy ornamental plants scale insects are best con¬ 
trolled by a delayed dormant application of miscible oil or con¬ 
centrated lime sulfur solution. 
SPIDER MITES. A number of different kinds infesting 
many plants. They are extremely small, greenish, reddish or 
brown, 4-legged creatures. They occur most abundantly on the 
lower surface of the leaves, often several hundred to a single 
leaf. Their injury can be determined by the fine speckled or 
mottled greenish or brownish appearance on the upper surface of 
the leaves. The small, round, pinkish eggs or white empty egg 
shells or cast skins are usually abundant and easily seen with a 
magnifying glass. 
Summer sprays containing pyrethrum or rotenone are more 
effective against spider mites than those containing nicotine. 
Sprays containing summer oils are also more effective than those 
containing soap or no wetting materials. The sprays should be 
diluted as directed on the container or usually at a strength 
about twice that given for plant lice. Be careful to wet the 
lower surface of all leaves and give two or three applications at 
intervals of about a week. Thorough applications, with superfine 
ground sulphur dust has been found most effective. The over¬ 
wintering eggs of spider mites on hardy plants may be destroyed 
by delayed dormant applications of a miscible oil. 
OTHER INSECTS. There are many other insects such as 
beetles of various kinds, some caterpillars, etc., that may be killed 
by summer contact sprays. If they are hardy insects the spray 
should be used from two to three times as strong as recommended 
for plant lice. 
DORMANT CONTACT SPRAYS 
Dormant sprays are used for the contral of the overwintering 
stage of certain insects on hardy plants. The dormant condition 
of the trees makes possible a stronger spray solution and the ab¬ 
sence of foliage on deciduous plants permits a more thorough 
application. Dormant sprays usually consist of oils made miscible 
with water or concentrated solutions of lime sulfur liquid. The 
miscible oils are usually used at dilutions of 1 part to 15 to 20 
parts of water and the lime sulfur solution at a dilution of 1 
part to 9 parts of water. Oil sprays are usually to be preferred 
but should not be used on hard maples, hickory, walnut, up-right 
type of junipers, or evergreen trees where the “bloom” will be 
destroyed. Lime sulfur should be used on such trees. Lime 
sulfur should not be used near buildings as it discolors badly. 
