Key Plant, Key Pests: Pine Species (Pinus sp.)

This series of Key Plant, Key Pests publications are designed for Florida gardeners, horticulturalists and landscape professionals to help identify common pests associated with common Florida flora. This publication, the seventh in the Key Plant, Key Pests series, helps identify the most common pests found on Pinus sp. This publication provides information and general management recommendations for borers, pine sawflies, pine bark beetles, pine tip moths, fusarium rust, pine chlorosis, and pitch canker.

Variation in Developmental Synchrony of the Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) with Implications for Chemical Control

Regional variation in developmental phenology of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was studied at four locations in southeastern Virginia and northeastern North Carolina. A companion study assessed the effects of developmental asynchronony on insecticide spray timing efficacy. Substantial variation in developmental synchrony was found within a relatively small area, with more synchronous development at Greensville and Isle of Wight Co., VA sites, and high levels of asynchrony at Sussex Co., VA, and Hertford Co., NC, sites. The Greensville Co. site showed a typical three generation developmental phenology, while the Isle of Wight Co. site had a more atypical two generation phenology. The Sussex and Hertford Co. sites appeared to have phenologies that were a combination of the other two sites. Spray timing evaluations with permethrin at the Sussex Co. site suggested that mid-April to early May and early to mid-July periods offer opportunities for effective chemical control of tip moths. These dates corresponded to the presence of high proportions of eggs and early-instar larvae in the field. Later season sprays were largely ineffective due to high developmental asynchrony, which resulted in the presence of high proportions of late-stage tip moths on virtually all collection and spray dates. Results suggest that multiple late-season treatments likely would be more effective. Overall, optimal spray dates at the Greensville Co. site, which had a typical three-generation tip moth developmental pattern, agreed most closely with published optimal spray period predictions which are based on historical temperature data.

Growth Impact of Pine Tip Moth on Loblolly Pine Plantations in the Ouachita Mountains of Arkansas

Growth impact of pine tip moths (Rhyacionia spp.) in two 12-year-old Arkansas loblolly pine (Pinus taeda L.) plantations was measured, and growth loss through rotation was projected. Two tip moth control treatments (azinphos-methyl foliar spray and carbofuran granules) were appliedto trees in the protected treatments at ages 3, 4, and 5, and growth was compared to unprotected trees at 2-year intervals. Trees in protected treatments had significantly greater average height (2.0 ft), dbh (0.35 in.), and total volume (182 ft³/ac) than did trees in the unprotectedtreatment. Volume losses at age 12 were proportional to tip moth infestation levels during the period of protection. Potential long-term impact of a tip moth was estimated using the results of this study as input to growth and yield models for thinned and unthinned stands. Projected gainsfrom early tip moth control in light to moderately infested stands were: unthinned, 2 to 6 cords/ac at age 30; thinned, 300 to 700 bf/ac of sawtimber and 1 to 3 cords/ac of pulpwood on a 35-year rotation. An economic analysis comparing the present value of growth benefits to the treatmentcosts showed tip moth control to be marginally cost effective only in the thinned, sawtimber regime. South J. Appl. For. 11(2):128-133

WESTERN RHYACIONIA (LEPIDOPTERA: TORTRICIDAE, OLETHREUTINAE) PINE TIP MOTHS TRAPPED USING SYNTHETIC SEX ATTRACTANTS

Synthetic sex attractants were used to trap Rhyacionia pine tip moths throughout the western United States in spring and early summer 1977 and 1978. Some species were shown to have much wider distributions than previously known. Among species responding to (E)-9-dodecenyl acetate, R. zozana was collected over most of the area, with new records for Washington, Idaho, Montana, Wyoming, and South Dakota; R. neomexicana was found for the first time in Utah, as was R. salmonicolor in New Mexico, Colorado, and Utah; R. monophylliana in Nevada and Utah; R. jenningsi in New Mexico; and R. multilineata in Arizona and Oregon. Among species caught in traps baited with (E,E)-8,10 dodecadienyl acetate, R. busckana was found widely through the Northwest, for the first time in Montana and Wyoming, and R. fumosana was captured throughout the Rocky Mountain states, with new records for Montana, Utah, and Nevada. Sets of two previously unknown zozana -like moths were collected. One is closely associated with the typical form in Oregon and California; the other is a pinyon associate in Colorado and New Mexico.