CHERRY INSECTS                                                          HOME

Insects troubling cherries are numerous but hardly as destructive as with other tree-fruits. Entomologists list about 40 species of insects attacking cherries and about as many more occasionally attack the varieties of one or the other of the two cultivated species. The majority of these pests came with the tree from its habitat over the sea but several have come from the wild cherries of this continent.

Of the pests peculiar to the cherry alone, possibly the cherry fruit maggot1 (Rhagoletis cingulata Loew) is, the country over, as troublesome as any. The adult insect is a small fly with barred wings which lays eggs under the skin of the cherry in mid-summer. From these eggs small, whitish maggots about one-third of an inch long hatch and eat out a cavity in the ripening fruit. These maggots when full grown pupate in the ground and remain there until the following season. The only effective preventive or remedial measure to take against the pest in large orchards is to spray with a sweetened arsenical, but in small plantations chickens are fairly effective in scratching up and eating the pupating maggots.

The cherry fruit maggot is probably responsible for most of the wormy cherries in New York but the plum curculio is also a cause of wormy fruits and in some seasons is a most formidable pest. This curculio2 (Conotrachelus nenuphar Herbst) is a rough, grayish snout-beetle somewhat less than a quarter of an inch in length, so familiar an insect as scarcely to need further description. The female beetle pierces the skin of the young cherries and places an egg in the puncture. About this cavity she gouges out a crescent-shaped trench, this cut or sting being a most discouraging sign to the cherry-grower, for he well knows that from the eggs come, within a week or two, white and footless grubs which burrow to the stone and make "wormy fruit."Some of the infested cherries drop but many remain eventually to distract the housewife and those who eat cherries out of hand. jarring the beetles from the trees, a method employed by plum-growers, is quite too expensive and ineffective for the cherry-grower and poisoning with an arsenate is the only practical means of combating the pest. Rubbish and vegetation offer hiding places for the insects and, therefore, cultivated orchards are freer from curculio than those laid down to grass. There are no curculio-proof cherries but, as with plums, the thin-skinned varieties are damaged most by the insect.

The grub of the plum curculio is easily distinguished from the cherry fruit maggot. This "worm "is the larva of a beetle, a true grub, footless and with a brownish, horny head while the cherry fruit maggot, the larva of a two-winged insect, is a true maggot like that which comes from the common housefly and hardly to be distinguished from the apple maggot. It is important to be able to distinguish in wormy cherries the grub of the curculio from the cherry fruit maggot in order to know and understand the nature of the two enemies in combating them.

Another pest of this fruit is the cherry leaf-beetle (Galerucellacavicollis Le Conte) the larvae of which sometimes do much damage to cherry foliage. The adult insect is an oval, reddish beetle about one-fourth of an inch long with black legs and antennae. Both the adult and the larvae feed on the leaves and do much damage if abundant. Usually there are two broods, the insect pupating in the ground. Fortunately the pest is easily controlled with the arsenical sprays.

The cherry scale (Aspidiotus forbesi Johnson) is commonly found on this fruit and occasionally on others as well. To the unaided eye it is very similar to the well-known San Jose scale, differing chiefly in being lighter in color. The remedy is the same as for the San Jose scale, which we next discuss.

The dreaded San Jose scale3 (Aspidiotus perniciosus Comstock) is rather less harmful to cherries than to other tree-fruits and yet is sometimes a serious pest on Sweet Cherries. Sour Cherries are almost immune. The insect is now so well known in all fruit-growing regions that it needs no description. It is usually first recognized by its work, evidence of its presence being dead or dying twigs oftentimes the whole tree is moribund. Examination shows the twigs or trees to be covered with myriads of minute scales, the size of a small pinhead, which give the infested bark a scurfy, ashy look. If the bark be cut or scraped a reddish discoloration is found. Leaves and fruit as well as bark are infested, the insidious pest, however, usually first gaining a foothold on the trunks or a large branch. Cherry-growers, in common with all fruit-growers, find the lime and sulphur solution the most effective spray in combating this insect.

Several other scale insects feed on the cherries and, now and then, become pestiferous; among these the following may be named: The European fruit lecanium4 (Lecanium corni Bouche) occasionally does a great deal of damage in New York and now and then destroys the whole crop in an orchard. The winter treatment for San Jose scale is used to control this pest, but usually such treatment is supplemented by a summer spray about July first with such contact sprays as whale oil soap and kerosene emulsion. The fruit pulvinaria (Pulvinaria amygdali Cockerell), the mealy bug (Pseudococcus longispinus Targioni), the scurfy scale (Chionaspis furfura Pitch), the West Indian peach scale (Aulacaspis pentagona Targioni), the Putnam scale (Aspidiotus ancylus Putnaxn), the walnut scale (Aspidiotus juglans-regiae Comstock), Howard's scale (Aspidiolus howardii Cockerell), the European fruit scale (Aspidiotus ostreaeformis Curtis), the red scale of California (Chrysomphalus aurantii Maskell), the oyster-shell scale (Lepidosaphes ulmi Linnaeus), and the soft scale (Coccus hesperidum Linnaeus), are all more or less cornmon.

Several borers occasionally infest cherry trees of which the peach borer5 (Sanninoidea exitiosa Say.) is the most troublesome. Larvae of the peach borer are frequently found in both Sweet and Sour Cherries, more particularly in Sweet Cherries, in eastern orchards. Fortunately this pest is not as rife with the cherry as with peaches and plums. Its work may be prevented by thorough cultivation, by mounding the trees and, according to some, by the use of a covering of tar or of obnoxious or poisonous washes. usually preventive measures are not effective, however, and the borer must be destroyed -best done by digging it out with a knife and wire. Since the pest is easily discovered through the exudation of gum mixed with sawdust or excreta, close to the surface or just beneath the ground, its presence can be detected in time to prevent its doing much damage. The lesser peach borer6 (Sesia pictipes Grote & Robinson) often attacks old or weakened cherry trees, working in the growing tissues of the trunk anywhere from the ground to the main branches. The worm is much like the common peach borer, known by all, but is smaller, rarely reaching the length of four-fifths of an inch when full grown. The flat headed apple tree borer7 (Chrysobothris femorata Fabricius) is a common pest in wild cherries and sometimes seriously attacks the cultivated species. It is treated as is the peach borer. The shot-hole borer8 (Eccoptogaster rugulosus Ratzeburg), though seldom injuring healthy trees, is very often a serious menace in old or decrepit cherry trees. It may be looked upon, however, as an effect rather than a cause. The peach bark-beetle9 (Phlzotribus liminaris Harris) is very similar in its work to the shot-hole borer and like it attacks only diseased and decrepit trees.

All cherry-growers are familiar with the small, dark green, slimy slugs which feed on the surface of the leaves of the cherry, possibly more common on the foliage of pears, eating out the soft tissues and leaving but the skeleton of the leaf. If the slugs are numerous the tree may be defoliated or if the leaves remain the foliage looks as if scorched. The adult of this slug is a sawfly (Caliroa (Eriocampoides) cerasi Linnaeus) which lays its eggs within the tissue of the leaves. Despite the fact that it is easily destroyed by any of the arsenical sprays or by dusting with lime this slug everywhere does much damage to cherries.

Wild cherries suffer severely from the tent caterpillar10(Malacosoma americana Fabricius) and occasionally cultivated trees are attacked. The arsenical sprays are fatal to the pest. The spring canker-worm11 (Paleacrita vernata Peck) and the fall canker-worm-12 (Alsophila pometaria Harris), the white-marked tussock moth (Hemerocampa leucostigma Smith and Abbot), the rusty tussock moth (Hemerocampa antiqua Linnaeus), and the definite-marked tussock moth (Hemerocampa definita Packard) are all occasional cherry pests and all succumb to poisonous sprays. The two now notorious European pests recently introduced into America, gypsy moth (Porthetria dispar Linnaeus) and the browntail moth (Euproctis chrysorrhaea Linnaeus), attack cherry trees in common with other deciduous trees and may often do considerable damage. Sometimes, but not often, the buds of the cherry are attacked by the bud-moth (Spilonota (Tmetocera) ocellana Schiffermueller), the caterpillars of which bind the young leaves together as they expand so that small, dead, brown clusters of foliage are to be seen here and there where the pests are at work. Spraying with arsenicals is effective if done just as the buds begin to open.

In sandy soils the cherry is sometimes attacked by hordes of the common rose-chafer (Macrodactylus subspinosus Fabricius), leaves, flowers and even the fruit suffering from the pest. It is a difficult insect to control but a spray of arsenate of lead with molasses is fairly effective. It is important to know that the insect does not often breed in ground kept in clean cultivation.

1 Slingerland, M.V. Bul. Cor. Ag. Ex. Sta. 272: 1899.
2 Riley,C.V. An. Rpt. State Entmo. Mo. 1:50-56. 1869:3:11-29. 1871.
3 Marlatt, C.L. The San Jose or Chinese Scale, U.S.D.A. Bw. Ent. Bul. 62:1-89. 1906.
4 Lowe, V.H. The New York Plum Lecanium, N. Y. Sta. Bul. 136:583-1897.
5 Beutenmueller, W. Sesiidae of America, etc. 266-271. 1901.
6 ibid. 291-292. 1901,
7 Riley,C.V. An. Rpt. State Entomo. Mo. 1:46-47-1869-
8 Lowe,V.H. N.Y. Sta. Bul. 180:122-128. 1900.
9 Wilson,W.F. The Peach-tree Bark-beetle, U.S.D.A. Bur. Ent. Bul. 68:91-108. 1909.
10 Lowe, V.H. The Apple-tree Tent Caterpillar, N. Y. Sta. Bul. 152:279-293. 1898.
11 Riley,C.V. An. Rpt. State Entom. Mo. 2:94-103. 1870.
12 Ibid. 7:83-90. 1875.