scholarly journals Analysis of Some Factors Associated With Distribution and Intensity of Attack by Cone and Seed Insects in Douglas Fir

1963 ◽  
Vol 39 (4) ◽  
pp. 488-489
Keyword(s):  
Douglas Fir ◽  
Factors Associated ◽  
Cone And Seed Insects ◽  
Seed Insects

DISPERSAL OF CONE AND SEED INSECTS TO AN ISOLATED DOUGLAS-FIR TREE IN WESTERN OREGON

1984 ◽  
Vol 116 (10) ◽  
pp. 1437-1438 ◽  
Author(s):  
T. D. Schowalter
Keyword(s):  
Pacific Northwest ◽  
Gall Midge ◽  
Douglas Fir ◽  
Control Measures ◽  
Host Trees ◽  
The Pacific ◽  
Major Species ◽  
Insect Populations ◽  
Cone And Seed Insects ◽  
Seed Insects

Cone and seed insects frequently cause severe losses to Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed production in the Pacific Northwest (Hedlin et al. 1981; Ruth 1980). Two of the major species west of the Cascades are the Douglas-fir cone gall midge (Contarinia oregonensis Foote (Diptera: Cecidomyiidae)) and the Douglas-fir seed chalcid (Megastigmus spermotrophus Wachtl. (Hymenoptera: Torymidae)). These two species are host specific on Douglas fir and exhibit an extended diapause in which more than 50% of each year's cohort may remain in diapause under host trees for 1 or more years (Annila 1982; Hedlin 1961; Hedlin et al. 1981; Johnson 1962). The economic and biological costs of chemical control have supported recommendation of alternative control measures, particularly (1) establishing seed orchards some distance from sources of coneand seed-insect populations, and (2) removing all cones and burning litter as a means of reducing such populations (Hedlin et al. 1981; Ruth 1980). The success of these two options depends on the dispersal strategies of cone and seed insects (Johnson 1962), but information on dispersal has been lacking. The purpose of this study was to obtain such information.

When Is Controlling Cone and Seed Insects in Douglas-fir Seed Orchards Justified?

1983 ◽  
Vol 59 (6) ◽  
pp. 304-307 ◽  
Author(s):  
G. E. Miller
Keyword(s):  
Douglas Fir ◽  
Critical Threshold ◽  
Threshold Values ◽  
Insect Infestation ◽  
Seed Orchards ◽  
Crop Size ◽  
Benefit Cost Analysis ◽  
Cone And Seed Insects ◽  
Benefit Cost ◽  
Seed Insects

Data from operational applications of dimethoate at two Douglas-fir seed orchards in British Columbia were used as base-lines for a benefit: cost analysis of protection of seed from cone and seed insects. Applications were economically justifiable provided that cone crop size and increased seed yield are above critical threshold values for given seed values and application costs. Sampling techniques for estimating crop size and insect infestation levels and expected damage are requisites for efficient orchard management where crop size and infestation levels fluctuate.

1- AND 2-YEAR DORMANCY OF THE DOUGLAS-FIR CONE MOTH, BARBARA COLFAXANA KFT. (LEPIDOPTERA: OLETHREUTIDAE): POSSIBLE RELATION TO INDIVIDUAL WEIGHTS

1991 ◽  
Vol 123 (5) ◽  
pp. 1153-1155 ◽  
Author(s):  
T.S. Sahota ◽  
A. Ibaraki
Keyword(s):  
Adult Population ◽  
Practical Importance ◽  
Douglas Fir ◽  
Teleological Reasoning ◽  
Higher Weights ◽  
Cone And Seed Insects ◽  
Seed Insects

Many cone and seed insects exhibit a dormancy in which the individuals may undergo a diapause that lasts 1, 2, or more winters and the proportion of 1-year diapause (1YD) and 2-year diapause (2YD) varies from year to year (Hedlin et al. 1980). Thus, segregating the two diapause types carries a practical importance for forecasting the attacking adult population in a given year. Based primarily on teleological reasoning it has been argued that insects committed to a longer dormancy may have higher weights with metabolites to sustain survival for a longer period. Individual weights have been examined with the hope of separating 1YD from 2YD individuals.

CONE AND SEED INSECTS IN DOUGLAS-FIR, PSEUDOTSUGA MENZIESII (MIRB.) FRANCO, SEED ORCHARDS IN THE WESTERN UNITED STATES: DISTRIBUTION AND RELATIVE IMPACT

1985 ◽  
Vol 117 (10) ◽  
pp. 1223-1230 ◽  
Author(s):  
T.D. Schowalter ◽  
M.I. Haverty ◽  
T.W. Koerber
Keyword(s):  
Pseudotsuga Menziesii ◽  
Gall Midge ◽  
Douglas Fir ◽  
Western United States ◽  
Seed Orchards ◽  
Or Management ◽  
Dioryctria Abietivorella ◽  
Explained Variation ◽  
Cone And Seed Insects ◽  
Seed Insects

AbstractDouglas-fir cones were collected from 17 seed orchards in California, Oregon, and Washington in the fall of 1983. Cones were completely dissected and seed losses ascribed to the Douglas-fir cone gall midge (Contarinia oregonensis (Foote)), the Douglas-fir seed chalcid (Megastigmus spermotrophus (Wachtl)), the Douglas-fir cone moth (Barbara colfaxiana (Kearfott)), and the fir coneworm (Dioryctria abietivorella (Groté)). There appear to be great differences between orchards, but overall C. oregonensis and M. spermotrophus collectively destroyed approximately 70% of the filled seed. Physiographic province significantly (P<0.05) explained variation in damage by all insect species between seed orchards. In general, damage by all species increased from northern provinces to southern mountainous provinces. Damage by C. oregonensis and B. colfaxiana appeared to be related to land use or management factors, as well.

SEQUENTIAL SAMPLING FOR IMPROVING CONE COLLECTION AND STUDYING DAMAGE BY CONE AND SEED INSECTS IN DOUGLAS FIR

1964 ◽  
Vol 40 (2) ◽  
pp. 210-218 ◽  
Author(s):  
A. Kozak
Keyword(s):  
Sequential Sampling ◽  
Douglas Fir ◽  
Cone And Seed Insects ◽  
Individual Trees ◽  
Seed Insects

The use of sequential sampling for ascertaining the production of filled seed and the damage by cone and seed insects is described for individual trees and stands of Douglas fir. Charts and tables are given for carrying out the sampling on individual trees. Recommendations are made for sampling of stands where the high tree-to-tree variation makes the use of sequential sampling of individual trees impractical.

Insects Affecting Seed Production in Red Pine: Part I Conophthorus resinosae Hopk. (Coleoptera: Scolytidae)

1956 ◽  
Vol 88 (10) ◽  
pp. 599-608 ◽  
Author(s):  
L. A. Lyons
Keyword(s):  
Seed Production ◽  
Pacific Coast ◽  
Large Numbers ◽  
The Pacific ◽  
Future Success ◽  
Loblolly Pines ◽  
Unfavourable Weather ◽  
Cone And Seed Insects ◽  
Seed Crops ◽  
Seed Insects

Natural and artificial reforestation, which basically depend on an abundance of sound seed, are adversely affected when insects destroy large numbers of cones, seeds, and cone-bearing shoots. Other factors, such as unfavourable weather, incomplete seed development, and damage by birds and mammals also reduce seed production, but they are rarely of such widespread importance as insects, whose damage often results in the failure of seed crops over large areas. Cone and seed insects sometimes restrict the natural regeneration of trees for a few years at a time, as, for example, in conifers on the Pacific coast (16), loblolly pines in Virginia (13), and oak in Michigan (5), but they become particularly important when the seeds they destroy are required for use in artificial reforestation. The future success of much reforestation, which is inclining more and more toward the use of seed obtained from trees cultivated especially for that purpose, may largely depend on a thorough understanding of cone and seed insects and their effect on seed production.

Evaluation of Aerial Applications of Acephate and Other Insecticides for Control of Cone and Seed Insects in Southern Pine Seed Orchards2

1992 ◽  
Vol 27 (2) ◽  
pp. 172-184
Author(s):  
Carl W. Fatzinger ◽  
Harry O. Yates ◽  
Larry R. Barber
Keyword(s):  
Loblolly Pine ◽  
Frost Damage ◽  
Slash Pine ◽  
Scale Insects ◽  
Southern Pine ◽  
Seed Orchards ◽  
Flower Thrips ◽  
Bacterium Bacillus ◽  
Cone And Seed Insects ◽  
Seed Insects

Acephate was evaluated for control of cone and seed insects in southern pine seed orchards from 1980 to 1985. Insecticides compared with acephate during this study were azinphosmethyl, fenvalerate, malathion, and the bacterium Bacillus thuringiensis. Insecticides were applied aerially, by hydraulic sprayers, and by airblast sprayers. Experiments were conducted in loblolly pine seed orchards in Florida and North Carolina and in two slash pine seed orchards in Florida. Control of coneworms, Dioryctria spp., slash pine flower thrips, Gnophothrips fuscus (Morgan), and two seed bugs, the leaffooted pine seed bug, Leptoglossus corculus (Say), and the shieldbacked pine seed bug, Tetyra bipunctata (Herrich-Schäffer) was evaluated. Frost damage and a serious infection of southern cone rust, Cronartium strobilinum (Arth.) Hedgc, and Hahn, caused significant flower and conelet losses and may have obscured differences between treatment effects during some years. All of the insecticide treatments were equally effective in controlling coneworms. The percentages of trees infested with pine tortoise scale, Toumeyella parvicornis (Cockerell), and the striped pine scale, T. pini (King), and the numbers of scale insects per branch after five applications of insecticide, differed significantly for acephate and fenvalerate treatments.

CONE AND SEED INSECTS OF TAMARACK, LARIX LARICINA (DU ROI) K. KOCH, AND ATTEMPTS TO CONTROL DAMAGE USING CHEMICAL INSECTICIDES

1986 ◽  
Vol 118 (6) ◽  
pp. 589-596 ◽  
Author(s):  
P.A. Amirault ◽  
N. Rae Brown
Keyword(s):  
New Brunswick ◽  
Choristoneura Fumiferana ◽  
Larix Laricina ◽  
Insect Damage ◽  
Weekly Basis ◽  
Breast Height ◽  
Growing Seasons ◽  
Protection Trees ◽  
Cone And Seed Insects ◽  
Seed Insects

AbstractAn investigation of the insects that damage cones (megasporangiate strobili) and seeds of tamarack [Larix laricina (Du Roi) K. Koch] in New Brunswick was undertaken. During two growing seasons (1982 and 1983) cones were removed from natural and planted stands of tamarack on a weekly basis. These cones were dissected, the nature and amount of insect damage recorded, and insect habits documented. Efforts were made to rear to adults any destructive insects encountered in order to identify them and to isolate parasites. Insects destroyed from 24.6 to 88.0% of the seed produced in the stands under study. Larvae of the spruce budworm [Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae)] and the cone maggot [Lasiomma viarium (Huckett) (Diptera: Anthomyiidae)] were responsible for most of the damage. Among insects that caused lesser amounts of damage were a cone midge [Resseliella sp. (Diptera: Cecidomyiidae)], a seed chalcid [Megastigmus sp. (Hymenoptera: Torymidae)], and various lepidopterous larvae. Applications of the insecticides carbofuran and dimethoate reduced the amount of insect damage. Carbofuran applied at the rate of 13.5 g active ingredient per centimetre of diameter at breast height provided the best protection. Trees treated in this manner had 37.0% of their seeds destroyed by insects as opposed to 74.2% on control trees.

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