The Common Asparagus Beetle

(Crioceris asparagi)



This beetle is by far the most important enemy of the asparagus plant.

It was first noticed in this country at Astoria, L. I., now a part of

New York City, in 1859, but its actual introduction into that locality

occurred about 1856. The injury inflicted by this insect is due to the

work of both adults and larvae upon the tender shoots, which they render

unfit for market, early in the season. Later they destroy, by

defoliation, growing plants, and are particularly injurious to

seedlings, the roots of which are weakened by having their tops

devoured. Larvae, as well as beetles, attack the tenderest portions of

the plants, but the latter gnaw with seemingly equal relish the

epidermis, or rind, of the stems. The beetles are also accused of

gnawing young shoots beneath the surface, causing them to become woody

and crooked in growth.



The beetle illustrated in Fig. 42 is a most beautiful creature--from the

entomologist's point of view--slender and graceful in form, blue-black

in color, with red thorax and lemon-yellow and dark blue elytra or wing

covers, with reddish border. Its length is a trifle less than one-fourth

of an inch.





From the scene of its first colonization in Queen's County, N. Y., the

insect migrated to the other truck-growing portions of Long Island. It

soon reached southern Connecticut, and has now extended its range

northward through Massachusetts to New Hampshire. Southward it has

traveled through New Jersey, where it was first noticed in 1868, to

southern Virginia. At present it is well established in the principal

asparagus-growing sections of New England, of New Jersey, Delaware, and

Maryland, and is present in Pennsylvania, New York, and Ohio. The

question of distribution is an important one, as this species is rapidly

extending its range. In a very few years we may expect its spread to

other portions of the States in which it is now local, and later it will

naturally move westward to Indiana and other States west and south of

there.



The insect passes the winter in the beetle state under convenient

shelter, and toward the end of April or early in May, according to

locality, or at the season for cutting the asparagus for market, issues

from its hibernating quarters and lays its eggs for the first brood. The

eggs are deposited endwise upon the stem or foliage, and in the early

spring upon the developed stalks, usually in rows of from two to six, or

more. In from three to eight days the eggs hatch, the young larvae,

commonly called "grubs" or "worms," presenting the appearance indicated

in Fig. 42, c. They at once begin to feed, and are from ten days to a

fortnight, according to Fitch and others, in attaining full growth. When

full grown the larva appears as in Fig. 42, d. It is soft and fleshy,

much wrinkled, and in color dark gray or olive, which usually becomes

lighter and yellowish with age. The mature larva enters the earth, and

here, within a little rounded, dirt-covered cocoon which it forms, the

pupa state is assumed. In from five to eight or more days the adult

beetle is produced, which soon issues from the ground in search of food

and of a suitable place for the continuance of the species. In Fig. 43

is shown a spray of asparagus, with the common asparagus beetle in its

different stages, asparagus top at the right showing eggs and injury.






The duration of the life cycle is about thirty days from the time the

eggs are laid until the insects attain maturity, but the time is shorter

in the hotter parts of a season than in the cooler days of May or

September. In the District of Columbia the eggs, in the warmest part of

midsummer, develop in three days and the pupae in five days. From this it

may be estimated that, in the very warmest weather, the development of

the insect may be effected in about three weeks from the time the egg is

laid. In colder climates and in spring and autumn the development from

egg to beetle will require from four to perhaps seven weeks. In the

northern range of the species, two and perhaps three broods are usually

produced, and farther southward there is a possibility of at least a

fourth generation. In the latitude of the District of Columbia the

beetles usually disappear to enter into hibernation in the latter days

of September.



The common asparagus beetle has very efficient checks in the shape of

predaceous insects, which prey upon its larvae and assist in preventing

its undue increase. One of the most active of these predaceous insects

is the spotted ladybird (Megilla maculata DeG.), represented in its

several stages in the illustration (Fig. 44.) The adult of this beetle

is rose-colored, with numerous black spots. The spined soldier-bug

(Podisus spinosus Dal.) and the bordered soldier-bug (Stiretrus

anchorado Fab.) are also useful as destroyers of asparagus beetle

larvae, which they catch and kill by impaling them upon their long beaks

and sucking out their juices. Certain species of wasps and small

dragon-flies also prey upon the larvae. Asparagus beetles are very

susceptible to sudden changes of temperature, and immense numbers of

hibernating beetles are sometimes killed in winter during severe cold

spells following "open" weather.





Remedies.--The common asparagus beetle, under ordinary circumstances,

may be held in restraint by the simplest means. Chickens and ducks are

efficient destroyers of the insect, and their services are often brought

into requisition for this purpose. A practice that is in high favor

among prominent asparagus growers is to cut down all plants, including

volunteer growth, in early spring to force the beetles to deposit their

eggs upon new shoots, which are then cut every day before the eggs have

time to hatch. Another measure of value consists in permitting a portion

of the shoots to grow and serve as lures for the beetles. Here they may

be killed with insecticides, or the plants, after they become covered

with eggs, may be cut down and burned, and other shoots be allowed to

grow up as decoys. One of the best and least expensive remedies against

the larvae is fresh air-slacked lime dusted on the plants in the early

morning while the dew is on. It quickly destroys all the grubs with

which it comes in contact. The lime may be conveniently applied by means

of a whisk-broom or a Paris green sifter. Even dry road dust applied in

this manner will have a beneficial effect. The special merit of these

insecticides is that they can be used without the least danger upon

young shoots being cut for market or home use.



Paris green and other arsenites, applied dry in powder, mixed with flour

or plaster, or in solution, answer equally well, after cutting has

ceased, and possess the advantage of destroying beetles as well as

larvae. One pound of Paris green to a barrel of fine plaster makes a

sufficiently strong mixture. It may be necessary to make two of these

applications at intervals or as often as the larvae reappear on the

plants. Powdered hellebore mixed with flour, one part to ten, or in

solution of one ounce of hellebore to three gallons of water, is also

very effective against the young larvae. Pyrethrum or buhach may be used

in similar manner, and kerosene emulsion has been highly recommended by

some experimenters. In hot weather, when the soil is dry, the larvae may

be brushed or shaken from the plants so that they will drop to the

heated ground, where they die, being unable to regain the shelter of the

plants. Whichever methods for the destruction of this pest are adopted,

unless the work be done thoroughly and with concerted action by all the

growers in the section, the relief can not be permanent.