THE HOWARD SCALE 
Aspidiotus howardi Ckll. 
(1906) 
Aspidiotus how'irdi Ckll., 
(1907) 
Gillette, Bull. 114, Colo. Agr. Exp. Sta. p. 16 
Taylor, Press Bull. 30 Colo. Agr. Exp. Sta. 
SUMMARY. 
(1) 1 he Howard scale is present in injurious numbers in many fruit 
orchards of Colorado. 
( 2 ) The pest was first discovered in this state and is supposed to 
have originated upon plants native to the locality. 
( 3 ) It is less destructive than the San Jose scale which, so far as 
is known, is not present in the state. 
(4) The insect has been found to infest many varieties of fruits, but 
is primarily a pest of pear, plum and prune. 
. (5) Damage may result from the insects attaching themselves to 
either tree or fruit, where they absorb the sap as parasite. Trees may be 
killed outright or fruit may be rendered unmarketable from its “scaly” 
appearance. 
( 6 ) The insects when attached to the surface of fruit or tree are 
of minute size—about the size of a pin head. 
(7) By rapid rate of increase they may produce enough individuals 
to completely encrust the surface of the plant attacked. It is their rate of 
increase and gregarious habit of life which make them so destructive. 
( 8 ) The female insects are wingless throughout their entire lives and 
except for a short period following hatching are entirely motionless. 
(9) The spread of the insect is dependent largely upon agencies out¬ 
side the control of the insect. 
( 10 ) Samples of scale insects found upon fruit trees should be sent 
to the entomologist of the Agricultural Experiment Station for determ¬ 
ination. 
( 11 ) Natural parasites and predaceous insects preying upon the pest 
do much to hold it in check but have not, in the past, increased enough to 
make other measures unnecessary. 
( 12 ) The lime-sulfur wash applied in late spring before the buds open 
has been found a complete and practical remedy. 
KEY TO ILLUSTRATIONS. 
Plate I.—I, Plant for steam cooking several barrels of lime-sulfur 
mixture at once, owned by Mr. John Ashenfelter, Montrose, Colo.; II, 
cooking lime-sulfur in kettles; III, Aspidiotus howardi , (A) scales upon 
pear twig, (B) dead females’ scales of last year, (C) young living 
female scales, (D) adult male scales, a male emerging at d—all enlarged 
seven times—drawn by Miriam A. Palmer; IV, photo of dead and living 
scale upon prune twig, considerably enlarged; V, pear showing large scales 
in depressions, also young white scales scattered about, somewhat enlarged; 
VI, pear with scales removed showing pits caused by the lice. 
Plate II.— Howard scale, Aspidiotus howardi Ckll. I, Pygidium of 
female showing dorsal characters on the left (A), and ventral characters on 
the right (B), a, wax ducts; b, oval dorsal glands; c, grouped ventral glands, 
X 190; II, the same, showing variation in the number and form of the 
glandular hairs or plates; III, newly hatched young, x 95; IV, adult male, 
X 62. Original drawings by Miss Miriam A. Palmer. 
Fig I.—Howard scale parasite, Prospalta aurantii greatly enlarged. 
After L. O. Howard, Bureau of Entomology, Washington, D. C. 
Fig. 2. — Twice stabbed lady-beetle. Chilocorus bivulverus ; larva, pupa 
and adult enlarged and the adult natural size. 
