Tip Moth Research Articles

Prediction models of Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lep., Tortricidae) infestation using soil and tree factors

Abstract: Prediction models for estimating infestations by Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock) in young loblolly pine plantations in East Texas were developed using multivariate regression analysis based on selected soil and tree factors. Results of regression models show that foliage nutrients, tree water potential and tree height play important roles in NPTM infestation. Overall, these factors predict whole tree infestation better than top two whorls infestation. The importance and correlation of the factors differed for the prediction model of top two whorl and whole tree infestations.

Observations on red cedar and the tip moth

Summary An account is given of the writer's involvement with the Australian red cedar (Toona ciliata), mainly during the 1950s and 60s, and its relationship with the tip moth Hypsipyla robusta. A record of some of the impacts of European settlement on the tree is presented, since its disastrous over-exploitation has resulted in its timber becoming a rare commodity. Past attempts to regenerate the tree are discussed and more recent investigations into the inter-relationships of the tree and the tip moth presented. The insect remains one of the major difficulties in regenerating the species. A silvicultural method, based on the results of these investigations, which minimises the effect of the insect's attack, is postulated for consideration.

Cedrela species are attacked by the tip moth Hypsipyla robusta when grafted on to red cedar Toona ciliata

Summary Australian Red Cedar (Toona ciliata) grown in plantation on the NSW mid-north coast is severely attacked by the shoot borer Hypsipyla robusta. Exotic species of Cedrela (C. odorata C, de Candolle and C. fissilis Vel.) grown in the same area are not attacked. Grafts were constructed using Cedrela spp. as scion and T. ciliata as root-stock. All grafts, when planted out in the field, were attacked by H. robusta. The results of this study provide a way forward for examining the notion that a factor(s) is translocated from T. ciliata root-stock to the Cedrela spp. and that this influences their resistance to H. robusta attack.

Comparison of Scotch Pine Christmas Tree Varieties in Virginia

Abstract Scotch pine (Pinus sylvestris) is a popular Christmas tree species throughout the country, but it is not widely grown in the southern United States. Many of the physical characteristics that influence Christmas tree quality are genetically influenced and vary with seed source. A study was established in Virginia to investigate Christmas tree marketability and quality from 17 commercial seed sources of Scotch pine. Nine test plantations, three each in the western mountains, Piedmont, and Coastal Plain, were established in 1987 and cultured for eight growing seasons. The study was terminated in the winter of 1995. Many differences were found in measured variables between seed sources and regions of the state, however, there were no significant source x region interactions. Four sources emerged as the top performers based on a tree value index: Lower Austria, Musser Special Strain, Belgium Campine, and Pennspanish. Two of these, the Musser and Pennspanish, are improved sources that have been selected for desirable Christmas tree traits. Although Scotch pine trees had greater heights and marketability factors in the western mountains of Virginia, the trees that became marketable in 8 years in the Piedmont and Coastal Plain had a mean USDA Tree Grade significantly lower than in the mountains. The Coastal Plain trees suffered reduced marketability due to Nantucket pine tip moth damage. Effective control of this pest would greatly improve the marketability of Scotch pine trees in the Coastal Plain. South. J. Appl. For. 21(2):57-63.

Plant Aging and the Distrihution of Rhyacionia neomexicana (Lepidoptera: Tortricidae)

A noted pattern of attack by larvae of pine tip moths, Rhyacionia spp., has been that young trees are susceptible and older trees remain unattacked. We undertook a quantitative test of this conventional wisdom and tested the following 4 hypotheses that may account for the pattern: (1) the plant age hypothesis, (2) the plant vigor hypothesis, (3) the plant stress hypothesis, and (4) the induced defense hypothesis. Ponderosa pine, Pinus ponderosa Lawson, near Flagstaff, AZ, were examined for attack by southwestern pine tip moths, Rhyacionia neomexicana (Dyar), over an age range of 300 yr. No current attacks were found on trees older than 20 yr or taller than 4 m tall, providing quantitative support for conventional wisdom and the plant age hypothesis. As trees aged, there was a significant increase in shoot diameter (r2 = 0.22, P < 0.0001) which could not account for the lack of attack after age 20. Within individual trees attack was concentrated on the largest shoots, supporting the plant vigor hypothesis instead of the plant stress hypothesis. Attack in previous years did not influence attack in the current year, indicating a lack of induced plant defense. The results indicate the importance of genetically regulated ontogenetic aging as a strong negative influence on attack. Yet within the young age group of attacked trees larger shoots were attacked more frequently than smaller shoots. The results suggest that shoot borers and shoot gallers show similar relationships to their host plants and aid in the recognition of broad patterns in plant-herbivore interactions.

Diel Activity Patterns and the Effects of Wind on the Mating Success of Red Cedar Tip Moth,Hypsipyla robustaMoore (Lepidoptera: Pyralidae)

Summary Diel patterns of adult emergence, female calling, mating, egg-laying and activity rhythms of red cedar tip moth, Hypsipyla robusta, were monitored in the laboratory under controlled temperature (26±2 °C) and reversed light cycles (14D: 10L). The effects of wind on mating success were studied in Perspex cages during the 10-hour night phase, with wind provided by a small electric fan. Most moths (82%) emerged in the early hours of the dark period (0–2.5 h after light-off). Peak female calling and mating activities were distributed at 5–7 h after light-off. Egg-laying was observed in all but the first 0.5 hour and the last 1.5 hours of the dark period. Individual moths, irrespective of their sex and mating history, periodically underwent rest during the dark period. Mated females showed the longest average duration of active intervals. Mating was significantly enhanced by wind. Simultaneous presence of wind was found not to be a prerequisite of the mating process. Implications of the diel activity rh...

Monoterpene emissions and cuticular lipids of loblolly and slash pines: potential bases for oviposition preference of the Nantucket pine tip moth

Monoterpene emissions from intact 5- to 29-month-old loblolly and slash pine seedlings contained α-pinene, camphene, β-pinene, myrcene, sabinene, β-phellandrene, and limonene. α-Pinene made up &gt; 50% of the volatiles from both species. β-Pinene was significantly more abundant in slash (35.6%) than in loblolly pine (15.3%), while myrcene was significantly more abundant in loblolly (10.9%) than in slash pine (3.4%). Cuticular lipids represented 0.11 and 0.06% of the dry weight biomass of shoots from loblolly and slash pines, respectively. Species differences in cuticular lipid composition were primarily in relative proportions of a group of unidentified compounds that appear to be saturated and unsaturated diols and (or) hydroxy alcohols with chain lengths of about 18 carbons. 10-Nonacosanol made up 16.2 and 14.1% of the total lipids recovered from loblolly and slash pines, respectively. The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), may use these chemical differences to distinguish the susceptible loblolly pines from the resistant slash pines. Key words: Pinus taeda, Pinus elliottii, monoterpene emissions, cuticular lipids, Rhyacionia frustrana.

PARASITOIDS OF COMOSTOLOPSIS GERMANA PROUT (LEPIDOPTERA: GEOMETRIDAE)

Diadegma sp. and Brachymeria sp. are recorded as parasitoids of bitou tip moth, Comostolopsis germana, an introduced biological control agent for bitou bush, Chrysanthemoides monilifera. These are the first Australian records of parasitoids of C. germana.

Sex Pheromone Chemistry of the Southwestern Pine Tip Moth (Lepidoptera: Tortricidae)

Chemical analyses and field bioassays were conducted to identify major components of the sex pheromone of the southwestern pine tip moth, Rhyacionia neomexicana (Dyar). E-9-dodecenyl acetate was the most abundant pheromone component in gland washes, with 0.5–1.5 ng per female equivalent. Z-9-dodecenyl acetate, and E and Z-9-dodecenol were also present. A ratio of about 80:20 E:Z-9-dodecenyl acetate was the most attractive bait in field trapping. No males were caught in traps baited with a blend of E and Z-9-dodecenol, and addition of these alcohols at about a 3: 1 acetate/alcohol ratio did not improve attractiveness to E and Z-9-dodecenyl acetate baits. The role of pheromones in mating isolation of Rhyacionia species is discussed.

Pine Tip Moth (Lepidoptera: Tortricidae) Infestation Rates as Influenced by Site and Stand Characteristics in Loblolly Pine Plantations in East Texas

Three young loblolly pine plantations grown on contrasting soil types produced quantitatively and qualitatively different host material for pine tip moths during 1985 and 1986. Amounts, periodicity, and availability of soil moisture regulated internal moisture conditions within host trees. Host xylem moisture potential in conjunction with soil nutrient status governed tree growth and influenced pine tip moth infestation rates. Pines on a sandy site exhibited the poorest growth with lowest infestation rates, indicative of low-quality hosts with little if any tolerance to damage. A clayey site produced vigorous plant growth with moderate infestation rates. The less apparent hosts appeared capable of withstanding pine tip moth attack and overcoming damage. Pines on a loamy site grew at moderate rates and received the highest infestation rates. This moderate growth indicated susceptible stand conditions.

Effects of Southwestern Pine Tip Moth and Vegetation Competition on Ponderosa Pine Growth

Abstract The effects of southwestern pine tip moth Rhyacionia neomexicana (Dyar) and vegetation competition on ponderosa pine Pinus ponderosa (Doug. ex Laws) growth was studied in northern Arizona. Tip moth attack rates varied significantly among three sites. Weeding had little effect on attack rates but increased tree survival by 17%, height growth by 96%, and diameter growth by 83%. Insectidde treatment for tip moth control increased height growth 49% and diameter growth only 12%. High tree mortality rates in insecticide treated plots suggest a possible phytotoxic effect of the insecticide. Tree growth declined as tip moth attacks increased. Height growth was further reduced with each added year of tip moth attack. Diameter growth was less affected by multiple years of attack. For. Sci. 38(1):173-186.

Distribution of damage by Rhyacionia, Blastesthia and Retinia tip moths (Lep., Tortricidae) depending on the exposure of planted and naturally seeded pine stands

AbstractPine stands younger than 15 years were examined for infestations by tip moths in three localities in southern and western Bohemia (360–510 m a.s.l.) in April‐June 1985–1988. Rhyacionia buoliana (Den. et Schiff.) was predominant in south Bohemia, near Kolný and Třeboň, Blastesthia spp. [especially B. posticana (Zett.)] in west Bohemia, near Plzeň. Insolated aftergrowth proved to be a reservoir of R. buoliana (53.1% dominance), aftergrowth shaded by old trees was the reservoir of Retinia resinella (L.) (46.1% dominance). Blastesthia spp. were found in plantations as well as in naturally seeded stands, especially insolated ones. Their dominance (25.7%) was highest along the southern edges of plantations.ZusammenfassungUntersuchungen zur Verteilung der durch Rhyacionia, Blastesthia und Retinia (Lep., Tortricidae) verursachten Schäden in Abhängigkeit von der Lage der gepflanzten oder natürlich verjüngten KiefernbeständeAn drei Standorten in Süd‐ und Westböhmen (Kolný, 510 m, Třeboň‐Vranín, 450 m, und Plzeň‐Bolevec, 360 m) wurden von 1985 bis 1988 in den Monaten April bis Juni Kiefernbestände bis zum Alter von 15 Jahren auf Wicklerbefall untersucht. In Südböhmen, in der Umgebung von Kolný, trat überwiegend Rhyacionia buoliana (Den. &amp; Schiff.) mit 4,4 Beschädigungen pro 100 Bäumen auf. Auch in der Umgebung von Třeboň überwog R. buoliana (3,8 Beschädigungen pro 100 Bäume). In Westböhmen, in der Nähe von Plzeň dominierte die Gattung Blastesthia mit 3,9 Beschädigungen pro 100 Bäume, davon 3,3 von B. posticana (Zett.) verursacht und 0,6 von B. turionella (L.). Besonnte Kiefernnaturverjüngungen erwiesen sich als ein Reservoir für R. buoliana; ihre Dominanz beträgt hier 53,1%. Von Überhältern beschattete Kiefernnaturverjüngungen werden von Retinia resinella (L.) bevorzugt (Dominanz 46,1%). Blastesthia spp. konnte sowohl auf Aufforstungsflächen wie in Naturverjüngungen festgestellt werden, insbesondere, wenn diese Flächen besonnt waren. Diese Art erreicht mit 25,7% an den südexponierten Rändern der Aufforstungsflächen ihre höchste Dichte.

Relation of Nantucket Pine Tip Moth Attack and Fusiform Rust Infection in Loblolly Pine Families

Abstract The relationship between pine tip moth attack and fusiform rust infection was studied in a 12-year-old loblolly pine stand in Houston County, GA. Four pine families were selected for study, and 24 trees of each family were felled for evaluation. The lower 8 ft of each tree was cut into two 4-ft sections and split to reveal the pith. Each section was examined for evidence of pine tip moth attack and the presence of fusiform rust galls. The analysis revealed 476 tip moth attacks and 99 fusiform rust galls. Forty-six of the rust galls occurred at the same place as a tip moth attack. These results, when combined with those of previous studies, suggest that the control of the pine tip moth may reduce the incidence of fusiform rust. Growth and yield simulations and economic analyses indicate that insecticide treatment of loblolly pine for the combined control of the pine tip moth and the associated reduction in levels of fusiform rust infection may be potentially cost effective in stands managed for sawtimber, but not for pulpwood. South. J. Appl. For. 15(4):204-208.

Pine Tip Moth, Rhyacionia spp., Response to Herbaceous Vegetation Control in an Intensively Site-Prepared Loblolly Pine Plantation

Abstract Herbicide release treatments were applied to an operationally regenerated loblolly pine (Pinus taeda L.) plantation to assess the effects of vegetation control on pine tip moth (Rhyacionia spp.) damage. Treatments included banded herbicide applications (1.5-m wide bands centered over rows of seedlings) for 1 or 2 years after planting, broadcast herbicide applications (total area covered) for 1 or 2 years after planting, and an untreated check. All of the herbicide treatments significantly reduced the mount of herbaceous vegetation and improved the survival and growth of planted pines. By the end of the third growing season, pine survival in the check plots (67%) was significantly less than survival in all of the herbicide-treated plots (≥92%). Trees in herbicide-treated plots suffered more tip moth damage than trees in the check plots during the first two growing seasons after planting, but by the third growing season, damage to trees in the check plots was equal to that in the herbidde-treated plots. The method or number of herbicide applications did not have a substantial effect on tip moth infestations. Pine growth gains resulting from reduced vegetative competition were more than enough to compensate for higher tip moth damage following herbicide treatments. However, increased tip moth damage still reduced potential growth gains. Two herbicide applications did not significantly improve pine survival or growth compared to one application, but the broadcast treatments produced slightly larger trees than the banded treatments by the end of the third growing season. For. Sci. 36(4):1105-1118.

Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Response to Water and Nutrient Status of Loblolly Pine

Abstract Loblolly pine (Pinus taeda L.) seedlings were grown in a greenhouse under conditions of variable water and nutrient availability and then exposed to natural populations of the Nantucket pine tip moth (Rhyacionia frustrana [Comstock]). Seedling growth was directly related to water and nutrient availability. Tip moth oviposition was highest on the most vigorous seedlings, even after accounting for differences in seedling size among treatments. The ratios of mean number of pupae per seedling to mean number of eggs per seedling for each treatment indicated percent tip moth survival may have been lower on vigorous seedlings than on stressed seedlings, but differences may have been due to factors other than the suitability of seedlings as larval food. Larger numbers of heavier pupae developed on vigorous seedlings than on stressed seedlings. Pupal weights were directly related to total nitrogen concentration and inversely related to total phenolic and condensed tannin concentrations of pine shoot tissues. Total phenolic and condensed tannin concentrations were inversely related to seedling growth. These results suggest that tip moth populations will increase rapidly following silvicultural treatments that increase water and nutrients available to young loblolly pines. For. Sci. 36(3):719-733.

Spatial Distribution of the Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) in Newly Established Loblolly Pine Plantations

The spatial distribution of trees infested by the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was examined using random 36 tree samples taken from contiguous quadrats in eight loblolly pine plantations in their first and second year of growth in southwestern Arkansas. Infestations were distributed throughout first-year plantations by the end of the second tip moth generation. The distribution of infested trees was generally random in the first generation, with increasing aggregation in subsequent generations. Factors such as vegetation level may alter this pattern.

Nantucket Pine Tip Moth Control in North Carolina, 1988

Abstract Two Christmas tree plantations of Virginia pines in Lenoir County, NC were selected to test 3 experimental insect growth regulators for efficacy. Three application rates each of RH-5849 and RH-5992, developed by Rohm and Haas Company, and 2 application rates of LAB 166 801 I, developed by BASF Corporation, were tested. RH-5849 and RH-5992 were applied with spreader-sticker triton B-1956 (4 oz/100 gal). Guthion and Dimilin were used as standards. Using a randomized block design, 3 blocks of 35 trees each in plantation I and 3 blocks of 25 trees each in plantation II were selected for treatments and controls. The trees were sprayed on 23 Jun in plantation I and 18 Aug in plantation II, 10 d after peak pheromone trap catch of adults, with a hand pump sprayer to the point of run-off. Each site was evaluated 5 wk after treatment. The dead terminals were examined for tip moth and counted on treated and untreated trees, using 3 center trees of each block in the evaluation.

Nantucket Pine Tip Moth Control in North Carolina, 1989

Abstract A Christmas tree plantation of Virginia pines in Wayne Co., NC was selected to test an experimental growth regulator for efficacy. RH-5992, developed by Rohm and Haas Company, was tested using 2 application rates and was applied with spreader-sticker triton B-1956 (4 oz/100 gal). Guthion and Dimilin were used as standards. Using a randomized block design, 4 blocks of 25 trees were selected for each treatment and controls. The trees were sprayed on 12 Apr, about 10 d after peak flight of adults, with a hand pump sprayer to the point of run-off. The trees were evaluated on 30 May, 7 wk after treatment. The dead terminals were examined for tip moth and counted on treated and untreated trees, using 3 center trees of each block in the evaluation.

MAPPING NANTUCKET PINE TIP MOTH (LEPIDOPTERA: TORTRICIDAE) PHENOLOGY IN GEORGIA

Thermal requirements for the Nantucket pine tip moth (NPTM), Rhyacionia frustrana (Comstock), to complete one generation were estimated using published data and new observations representing six unique combinations of location and year. Estimates ranged from 690 degree-days (DD) to 818 DD using a lower threshold of 9.5° C and an upper threshold of 33.5° C. Selected values within the range of estimates were used along with historical temperature data to produce maps of NPTM phenology in Georgia. The map based on the midpoint of the range of estimates (754 DD) was most closely compatible with previous observations of NPTM phenology and major physiographic boundaries. With an estimated mean thermal requirement of 754 DD, the NPTM will complete two to four generations per year in Georgia. This study demonstrates a technique that could be applied to map the phenology of any multivoltine insect for which data on thermal requirements for development are available.

Hazard Rating Forest Sites for Pine Tip Moth, Rhyacionia spp., in the Upper Piedmont Plateau

Abstract Hazard rating models for pine tip moths (Rhyacionia spp.) were developed from vegetative, physiographic, and other site characteristics of loblolly pine (Pinus taeda L.) stands in the upper Piedmont of South Carolina. Results of regression models show that site preparation intensity, site index, soil calcium, and depth of the "A" horizon are the most important predictors of tip moth infestation levels. For management of loblolly pine, minimum site preparation and forest practices that favor high site quality will reduce the hazard of tip moth. The severity of tip moth damage to loblolly pine stands is inversely related to site quality and positively related to the intensity of site preparation. For. Sci. 34(4): 1083-1093.