SPRINGFIELD, N. J. 
67 
CONTACT SPRAYS FOR PLANT LICE —Continued 
sprays diluted with water as recommended on the container. Be careful 
to wet the lower surface of the leaves. It is often advisable to give a 
second treatment in 5 to 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, waxlike material. The eggs are pinkish, 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 possible 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 ma¬ 
terial 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 through 
syringe with clean water and spray with the regular strength recom¬ 
mended for mealy bugs. 
SCALE INSECTS. Two types are commonly found on ornamental 
plants. One type is called armored scales because the body is covered 
with a round or oval, flat, waxlike scale, usually not more than 34 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 hemi¬ 
spherical in shape and from 24 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 con¬ 
trol of plant lice, will kill the young insects and clean uo an infestation. 
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 controlled by a delayed dormant 
application of miscible oil or concentrated lime sulphur 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 deter¬ 
mined 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 control of the overwintering stage of 
certain insects on hardy plants. The dormant condition of the trees 
makes possible a stronger spray solution and the absence of foliage on 
deciduous plants permits a more thorough application. Dormant sprays 
usually consist of oils made miscible with water or concentrated solu¬ 
tions of lime sulphur liquid. The miscible oils are usually used at 
dilutions of 1 part to 15 to 20 parts of water and the lime sulphur solu¬ 
tion 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 sulphur should be used on such trees. Lime sulphur 
should not be used near buildings as it discolors badly. 
Dormant sprays are usually used for control of the eggs of plant 
lice, spider mites and other stages of insects that might hibernate on 
the trees or shrubs. 
