Egg-The egg is slightly convex and approximately 0.75 mm in diameter. It is opaque white to yellow or medium orange.
Larva-The tiny larva is cream colored with a black head. The mature larva is light brown to orange and approximately 10 mm long.
Pupa-The pupa is light to dark brown and approximately 6 mm long.
Host Plants -Within its range, the Nantucket pine tip moth feeds on nearly all species of pine except longleaf and eastern white pines. Slash pine is also somewhat resistant, but it is occasionally attacked. In the Southeast, loblolly and shortleaf pines are preferred hosts.
DamageThis pest causes the retardation of height growth, crooking or forking of main stems, reduction of cone crops, and occasionally the death of the tree. Attacks are generally restricted to trees under 4.6 m (15 feet) tall and to young plantations, though severe attacks on commercial-sized trees have been reported.
Life History -The Nantucket pine tip moth is an important pest of pines grown in plantations in the eastern United States. Because the establishment of large pine plantations is becoming increasingly popular, the importance of this insect is also increasing.
In the Southeast, Nantucket pine tip moths overwinter as pupae within the injured tips of pines. On warm days as early as February, adults emerge and mate. They lay eggs on needles, in the axils of needles and stems, and on developing tips or buds. The egg stage lasts about 30 days in cool spring weather and 5 to 10 days in summer.
Newly hatched larvae either feed on the surface of new growth, causing shallow injuries, or bore into the needle bundles. Later they migrate to the shoot tips, construct a protective web at the base of the buds, and begin to bore into the bud or stem. Feeding continues inside these tissues until larvae are fully grown (3 to 4 weeks). Pupation then occurs within the cavities formed by the larvae. In the Southeast, there are three generations per year.
Cultural practices are the most effective means of control. Before outplanting, seedlings should be inspected and injured buds and twigs should be destroyed. Infested trees should be pruned well below the dead part because larvae normally feed in the green tissue there. In areas with a history of heavy infestation, planting of loblolly and shortleaf pines should be avoided except on sites most suitable for quick growth. Anything that encourages rapid development, such as vigorous tree strains or ideal sites, helps reduce damage. Seedlings on barren soils along roadsidefences are heavily infested throughout the South. Since these trees are sources of infestation for nearby young plantations, they should be cut and burned.
Some natural control of the Nantucket pine tip moth does exist. More than 30 known species of parasites, as well as several predatory insects and birds, attack this pest.
Large-scale use of insecticides is not usually recommended. Such use may be justified, however, in areas of high value, such as seed orchards or forest tree nurseries, where power sprayers can be used and the high cost of applicationis not prohibitive.
To obtain control throughout the season, spraying m be necessary for each generation of the moth. The spray should be directed at the young larvae, which feed on the exterior of the shoot for a period of several days. Larva begin to hatch 5 to 10 days after peak adult Emergency When cool weather follows this peak in early spring, spraying should be deferred for about 14 days. For specific chemical controls, see the current state extension service recommendations.
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