I. Introduction: Oriental fruit moth (OFM), introduced in the U.S. on nursery stock from Japan between 1913 and 1916, is a serious stone fruit pest in the mid-Atlantic region. This species can be found in various stages during the entire growing season, and is the main reason for season-long, repeated insecticide applications.

II. Hosts: This insect infests all stone fruit, plus apple and pear. Late ripening peach cultivars are particularly vulnerable to OFM. During its life cycle it may also utilize orchard trash, mummified fruits and weed hosts for cocoon sites.

III. Description: The adult is a small grayish, mottled mothabout 1/4 inch (6-7 mm) long, with a wingspan of about 1/2 inch (13 mm) (photo 1). Wings are held roof-like over its body when at rest. Eggs are flat, oval and whitish, and are laid singly on twigs or the undersides of leaves near growing terminals, or on water sprouts. Newly hatched larvae are 1/16 inch (1.5 mm) long and are cream colored with a black head. Older larvae have a brown head capsule, are slightly pink, and grow to about 5/16 to 1/2 inch (8-13 mm) long. Larvae have three pairs of true legs, and four pairs of prolegs located on the third, fourth, fifth, and sixth abdominal segments. An anal comb with five "teeth" on the last abdominal segment distinguishes OFM larvae from some other larvae which may feed inside fruit.

IV. Biology: Full grown larvae overwinter in cocoons in bark crevices, orchard trash, weeds, ground cover, and in fallen or mummified fruit. Larvae pupate in March, with emergence of adults beginning by the pink to bloom stage of bud development, depending on variety and geographical location. There are four to five generations per year in the mid-Atlantic region. In southern New Jersey, flight peaks usually occur during the first week of May, mid-June, mid-July, and late August. The adult female may lay up to 200 eggs in her lifetime. Eggs may take up to three weeks to hatch during cool spring weather, but need only three to four days during hot summer weather. After eggs hatch, first and some second brood larvae bore into new growth stems and exit 1.5 to 5 weeks later, depending on the temperature. Larvae will tunnel up to six inches (15 cm) into the shoot, or they may exit and enter one or more new shoots before maturing. Adult females of later generations of OFM lay eggs directly on the fruit, where the larvae bore in and feed. Most summer cocoons are formed on the tree.

V. Injury: Infested shoots and terminal leaves wilt and bend over (photo 2). After larval emergence, the entire shoot tip and its leaves dry up, and bend down even further (photo 3). This injury is known as "flagging." Flagging stimulates lateral growth below the point of injury, which can inhibit good scaffold limb formation in young trees, and provides wound sites for pathogens. Crooked branches may also result from terminal injury, but is usually of minor importance.

Fruit injury (photo 4) is more critical than terminal flagging, and may occur either early in the season on young fruit, or later after pit hardening to final swell. Injury is rarely seen on young or green fruit in sprayed blocks, but may still be found at harvest. Mid-season larvae will usually enter fruit from the stem end, and where two fruit touch. Larvae of later broods will enter anywhere on the fruit. Gum and frass may be exuded from the wound area as the larva bores into the fruit. As the gum ages, a sooty mold may form on it, turning the entire wound area black. Late-season larvae may occasionally enter fruit through the inside of the stem, and therefore leave no evidence of entry except for a small mark at the stem end of the picked fruit.

OFM may cause injury to apple similar to codling moth (CM). Apple blocks adjacent to those of peach and nectarine are most vulnerable to attack, especially when these stone fruits are not sprayed because of crop loss due to cold temperatures.

Begin weekly examination of five to ten trees per orchard for shoot (flagging) injury (photo 2) at shuck split and record the number of injured shoots per sample tree. In mid-June, begin weekly examinations of 25 to 50 fruits on each of five to ten trees per orchard for evidence of larval entry (photo 4), with special attention paid to the stem ends of the fruit as the season progresses. For each orchard block, evaluate a 100-fruit sample from each of five trees or bins at harvest to determine the percent injury from OFM.