Several applications of poisons have been used, the best results being obtained from the use of pyrethrum as a powder blown on to the plants by a hand bellows, during the hottest part of the day, in the proportion of one part to four or five of flour.

As the eggs are laid at different times, any application, to be thoroughly tested, must be repeated several times.

THE APPLE TREE TENT CATERPILLAR.

Clisiocampa Americana (Harr.)

Large, white, silken web-like tents, Fig. 15, are noticed by the roadsides, in the early summer, on wild cherry trees, and also on fruit trees in orchards, containing numerous caterpillars of a blackish color, with fine gray hairs scattered over the body.

This well known pest has been very abundant throughout the State for several years past, and the trees in many neglected orchards have been greatly injured by it, some being entirely stripped of their leaves.  The trees in these orchards and the neglected ones by the roadsides form excellent breeding places for this insect, and such as are of little of no value should be destroyed.  If this were well done, and all fruit growers in any given region were to destroy all the tents on their trees, even for a single season, the work of holding them in check or destroying them in the following year would be comparatively light.

[Illustration:  Fig. 15.]

The moths, Fig. 16, appear in great numbers in July, their wings measuring, when expanded, from one and a quarter to one and a half inches or more.  They are of a reddish brown color, the fore wings being tinged with gray on the base and middle, and crossed by two oblique whitish stripes.

[Illustration:  Fig. 16.]

The females lay their eggs, about three hundred in number, in a belt, Fig. 15, c, around the twigs of apple, cherry, and a few other trees, the belt being covered by a thick coating of glutinous matter, which probably serves as a protection against the cold weather during winter.

The following spring, when the buds begin to swell, the egg hatch and the young caterpillar seek some fork of a branch, where they rest side by side.  They are about one-tenth of an inch long, of a blackish color, with numerous fine gray hairs on the body.  They feed on the young and tender leaves, eating on an average two apiece each day.  Therefore the young of one pair of moths would consume from ten to twelve thousand leaves; and it is not uncommon to see from six to eight nests or tents on a single tree, from which no less than seventy-five thousand leaves would be destroyed—­a drain no tree can long endure.

As the caterpillars grow, a new and much larger skin is formed underneath the old one, which splits along the back and is cast off.  When fully grown, Fig. 15, a and b, which is in about thirty-five to forty days after emerging from the eggs, they are about two inches long, with a black head and body, with numerous yellowish hairs on the surface, with a white stripe along the middle of the back, and minute whitish or yellowish streaks, which are broken and irregular along the sides; and there is also a row of transverse, small, pale blue spots along each side of the back.