Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Superorder	Holometabola
Order	Lepidoptera
Superfamily	Sesiodea
Family	Sesiidae
Subfamily	Sesiinae
Tribe	Synanthedonini
Genus	Synanthedon

Scientific Name

Synanthedon exitiosa

Common Name

peachtree borer

Author: Dr. H C Ellis, Dr. D. L. Horton, The University of Georgia, Department of Entomology.

Description

Adults are clearwinged moths with a wingspan of 27 to 38 mm. Males are bright steel blue with pale yellow, narrow bands around the abdomen. Females are darker, steel blue except for a broad, orange band on the fourth abdominal segment. The hindwings of both sexes are clear. Larvae are white or cream-colored with a brown head. Older larvae have a dark schlerotized area on the prothorax and on the last segment of the abdomen. They are 19 to 24 mm long.

Hosts

Peach, plum, prune, apricot

Damage

Larvae feed on the cambium and inner bark of the lower trunk, usually just below the soil surface. Large gum masses often indicate infestation. Feeding may also injure the larger roots. Small trees are sometimes completely girdled and killed.

Life Cycle

Overwinter as larvae in trees. Adults emerge from May to October with peaks in early and late summer. Oviposition usually begins the day of emergence. Females lay from 200 to 800 eggs, most on the lower 15 cm of the trunk and on the soil nearby. Eggs hatch in about a week. Newly hatched larvae chew through the bark at the base of trees and move to the cambium. Larvae feed in the tree until overwintering. Pupation occurs beneath the bark just below ground line. The pupal stage lasts about three weeks. There is usually one generation per year but sometimes two.

Control

Several natural enemies attack peachtree borer and disruption of mating with synthetic pheromone has also been effective in field trials. Chemical control remains the best management tool. Insecticides may be sprayed between August 1st and again in September in northern and middle Georgia. In south Georgia, sprays should be applied immediately after harvest and again after September 1st. Thorough coverage of the trunks and soil at the base of the trees is critical. Home orchardists can kill or remove the borers by hand.

Originally compiled from

Ellis, H.C. and D. L. Horton. Peachtree Borer. The University of Georgia.

Hosts

The commercial fruit trees--peach, plum, (including prune varieties), nectarine, cherry, apricot, and almond--as well as black cherry. Original host plants were wild cherry and wild plum until early settlers introduced the peach (Gossard and King 1918, Snapp and Thomson 1943). Now it is a major pest of both fruit-bearing and flowering varieties of the genus Prunus (Russell and Stanley 1969). Although this borer attacks several kinds of fruit and ornamental trees and shrubs, the peach tree is its most common host (Russell and Stanley 1969).

Range

A native of the United States found in most peach-growing areas of the United States. Occurs mainly east of the Rocky Mountains from Canada to the Gulf of Mexico, where it is more important as an economic pest than it is in the Rocky Mountain and Pacific Coast regions (Snapp and Thomson 1943).

Description

Adult

Bluish black clearwing moth with wingspan of 27 to 38 mm and body length of 17 to 23 mm. Body scales of males bright steel blue; pale yellow to white narrow banding around abdomen; forewings and hindwings clear. In females, front wings, legs, and body, except for broad band of orange to reddish scales on fourth abdominal segment, covered with dark steel-blue scales; hindwings of females clear. Several color forms with variations in wing scaling and abdominal banding exist over its range (Engelhardt 1946).

Egg

Dark to light brown, somewhat flattened, depressed or concave on one side, with one end slightly broader than other. Eggs mesure about 0.7 mm long, 0.5 mm wide, and 0.3 mm thick (Snapp and Thompson 1943).

Larva

Young larva, grayish white with brown head; older larva, white or cream colored with dark brown head and sclerotized area dorsally on prothorax and another on last segment of abdomen. Young larvae 1.5 to 1.7 mm long; mature larvae 32 to 38 mm long.

Pupa

White when first formed but soon changing to bright brown; 19 to 24 mm long (Snapp and Thompson 1943). Protected inside frass- or soil-coated cocoons, from which they exit for moth emergence.

Biology

Adults emerge in May to October, with peaks in early and late summer. Moths mate soon after emergence and live on a few days. Adult have not been observed to feed in the field (Russell and Stanley 1969). Oviposition typically begins the day of emergence but occasionally does not start until the second day. Females typically deposit from 200 to 800 eggs, but a few lay more than 1,200 eggs. Eggs are usually deposited singly in small groups, mostly on host trees adjacent to or near the emergence site. Sometimes, eggs are laid on all parts of a tree and occasionally on weeds, grass, debris, and bare soil around the trunk. Most eggs, however, are laid on the lower 15 cm of the trunk and on the soil nearby (Snapp and Thomson 1943). At 27o C, eggs hatch in about a week. Newly hatched larvae move to the base of trees, usually near the soil line, where they chew through the bark to the cambium. Wounds or breaks in the bark are not needed for entry (Russell and Stanley 1969). The peachtree borer usually has one generation per year (King and Morris 1956, Russell and Stanley 1969) but sometimes it has two generations (Snapp and Thomson 1943). After overwintering, larvae usually build cocoons beneath the bark, on the trunk just below the groundline, or at the soil surface under gum exudates. Pupation occurs inside cocoons and lasts about 3 weeks (Russell and Stanley 1969).

Injury and Damage

Large masses of gum exudate, particles of bark, and frass at the base of a tree are evidence of infestation. Damage results from larvae feeding on the cambium and inner bark of the lower trunk, usually just below the soil but sometimes just above ground. Feeding also may injure the larger roots (Snapp and Thompson 1943). Larvae usually attack only after trees are about 50 mm or greater in diameter (Dorn and Auchmoody 1974). They sometimes girdle young trees (and less commonly girdle older trees) and damage is often severe. In some areas, only one or two borers inhabit an infested tree; in other areas, many borers may be in a tree. Trees with old damage are more susceptible and repeated attacks and to invasion by fungi (Russell and Stanley 1969). Occasionally the peachtree borer has killed young black cherry trees in seed orchards in the Allegheny and Monongahela National Forests (Dorn and Auchmoody 1974). More recently this borer has injured trees in black cherry seed orchards in North Carolina. It also causes minor defects in sawtimber trees.

Control

Natural enemies include the egg parasite Telenomus quaintancei Girault (Muesebeck 1979) and the following larval hymenopterous parasites--Macrocentrus marginator (Nees), Microbracon sanninoideae (Gahan) (Marsh 1979), Cryptus rufovinctus Pratt, Phaeogenes ater Cresson (Carlson 1979), Hyssopus sanninoideae (Girault), Syntomosphyrum clisiocampae (Ashmead), and Venturia nigricoxalis (Cushman) (Burks 1979)--and the pupal dipterous parasite Anthrax lateralis Say (Arnaud 1978). Important predators are field mice and rate, which sometimes greately reduce populations by destroying pupae. Other predators include ants, chrysopid larvae, spiders, moles, and skunks (Snapp and Thompson 1943). Several insecticides effectively reduce populations (Dorn and Auchmoody 1974, Russell and Stanley 1969, Wylie 1968). Disruption of mating communication with synthetic pheromone has been very effective in field trials.

Gallery

References

Solomon, J.D. 1995. Guide to insect borers of North American broadleaf trees and shrubs. Argic. Handbk. 706. Washington, DC: U.S. Department of Agriculture, Forest Service. 735 p.