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Insects: DIAGNOSTICS

Horticultural Diseases and Pests - Alphabetically
Horticultural Diseases and Pests - by Host

Pine Tip Moth

Hosts:

(Nantucket) Pine Tip Moth attack virtually all species of two-needle and three-needle pines, preferred hosts include loblolly and shortleaf pine (two common native species in Oklahoma), Virginia and Scotch pine, and mugho and Japanese black pine.

Description:

The Nantucket pine tip moth overwinters as pupae in the damaged branch terminals of infested pine trees. Adults emerge from these pupae in March and April and then mate. Eggs are laid on the needles and the newly hatched larva constructs a small silken web in the axil formed by a needle and the stem. The larvae feed for a few days on the base of the needles and on the surface of the stem. Resin and frass accumulate on and around the web as they feed. Later, they migrate to the shoot tips, construct a new protective web, and tunnel into the stem or bud. Feeding continues inside the stem until larvae are fully grown, Pupation occurs within the cavities formed by the larvae. There are four or more generations per year in Oklahoma.

Symptoms:

The first sign of damage is the browning and dying of a few needles at the tips of the branches. As the larvae burrow into the stems, the branch tips die and turn brown with additional feeding, this dead area extends down the twig. Most severe damage occurs on susceptible species of pines that are less than 15 feet tall and growing in open areas.

Control:

Maintenance of high tree vigor by fertilization and irrigation is an effective method of reducing damage. This also promotes rapid growth through the first six to eight years, when the tree is most susceptible to injury. Practices such as close spacing and planting under the canopy of older trees may also help reduce tip moth populations and subsequent damage. Historically, the most effective method of managing the tip moth has been and continues to be the timely application of insecticides.