Feeding by Leptoglossus occidentalis (Hemiptera: Coreidae) reduces seed set in lodgepole pine (Pinaceae)

2001 ◽  
Vol 133 (6) ◽  
pp. 857-865 ◽  
Author(s):  
Ward B. Strong ◽  
Sarah L. Bates ◽  
Michael U. Stoehr

AbstractLow seed set is a serious problem in seed orchards of lodgepole pine (Pinus contorta var. latifolia Engelmann) in the southern interior of British Columbia. We tested the hypothesis that Leptoglossus occidentalis Heidemann is responsible for the low seed set. Cones enclosed in insect exclusion bags as part of a pollination experiment produced significantly more filled seeds per cone than cones that were not bagged. In a separate bagging experiment, cones that were enclosed with a L. occidentalis female and her progeny produced only about one filled seed per cone, compared with about 28 seeds in bagged control cones. Changes in microclimate associated with the use of bags did not appear to be responsible for the observed increase in seed set in bagged cones. Leptoglossus occidentalis was also excluded from trees using the insecticide fenvalerate. Cones on fenvalerate-treated trees produced > 11 filled seeds per cone, whereas water-treated (control) cones produced < 1.7 filled seeds. These data suggest that L. occidentalis should be considered a serious pest in lodgepole pine seed orchards.

2006 ◽  
Vol 138 (6) ◽  
pp. 888-896 ◽  
Author(s):  
Ward B. Strong

AbstractManagement of Leptoglossus occidentalis Heidemann in lodgepole pine (Pinus contorta var. latifolia Engelm.) seed orchards of British Columbia, Canada, would be improved with knowledge of its damage potential at different times of the growing season. Mesh insect-exclusion bags were placed over cones, and adults or nymphs of L. occidentalis were enclosed in different bags for 9 periods of 10 to 38 days between 6 May and 17 September 2004. Feeding by adult females between 6 May and 28 May reduced total extractable seeds, a result of ovule damage before fertilization. Reduction in the number of filled seeds per cone was highest between 6 May and 29 June, with each adult female reducing yield by approximately 1.7 seeds per day. Between 29 June and 10 August, each adult female reduced the number of filled seeds per cone (seed set) by 1.0 to 1.25 per day. Seed set reduction declined to approximately 0.25 filled seeds per adult female per day after 10 August. Third to fifth instars caused seed set reduction between 0.6 and 1.2 filled seeds per cone per nymph feeding day from 29 June to 10 August. Utilizing these findings would improve management of L. occidentalis in a commercial seed orchard setting.


1996 ◽  
Vol 128 (6) ◽  
pp. 1065-1076 ◽  
Author(s):  
Suzie E. Blatt ◽  
John H. Borden

AbstractLeptoglossus occidentalis Heidemann (Hemiptera: Coreidae) is considered to be an important cone and seed pest in seed orchards in British Columbia; however, no impact studies have been done in Canada. Surveys to determine the distribution of L. occidentalis were conducted over a 3-year period in three coastal seed orchards of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and over a 2-year period in two seed orchards of lodgepole pine, Pinus contorta var. latifolia Engelmann. Leptoglossus occidentalis was found to distribute itself in patches, coinciding with a clonal preference. Seed losses were assessed for 2 years in the coastal Douglas-fir orchards and for 1 year in one lodgepole pine orchard. The percentages of partially filled seed that could have been caused by feeding of L. occidentalis or by a number of other factors were < 5% in coastal Douglas-fir for both 1992 and 1993 and ~14% in lodgepole pine in 1993. Apparently because populations of L. occidentalis were low, there was no correlation between the percentage of partially filled seed and number of insects per tree. Except in unusual circumstances, management measures in Canada are judged not to be necessary as populations of L. occidentalis are consistently below the calculated threshold levels required to cause ≥5% loss in seed production.


Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 23-33
Author(s):  
Paul Y. de la Bastide ◽  
Jonathon LeBlanc ◽  
Lisheng Kong ◽  
Terrie Finston ◽  
Emily M. May ◽  
...  

Lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) is an important lumber species in Canada, and seed orchards are expected to meet the increased demand for seed. However, seed production has been consistently low in the Okanagan region orchards of British Columbia, Canada. To determine whether the fungal microbiome contributes to seed loss, histological and molecular approaches were used. Seed production was studied at seven Okanagan orchards, all outside the natural range of lodgepole pine, and at one near Prince George, within its natural range. Seed losses were highest in the Okanagan, compared with Prince George. The role of fungal colonizers in consuming seed during the last stages of maturation is described. Fungal hyphae were frequently observed at all locations in developing seed, particularly once storage substances accumulated. Fungi identified from host tissues using molecular and morphological techniques included Alternaria, Cladosporium, Fusarium, Penicillium, and Sydowia. The opportunistic foliar pathogen Sydowia polyspora, which is known to have a variable biotrophic status, was detected at most orchards within different host tissues (seeds, needles, and conelets), in association with pollen, and in the air column. Reduced seed viability observed in Okanagan orchards is most likely due to a combination of factors, including composition of the fungal microbiome.


2005 ◽  
Vol 20 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Wayne D. Johnstone

Abstract The effects of spacing 7-year-old second-growth lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) are reported 20 growing seasons after treatment. Five spacing levels of 500, 1,000, 1,500, 2,000, and 2,500 trees per hectare, plus unspaced controls, were established on plots in central British Columbia. Both individual-tree and per-hectare data were analyzed. Spacing had a significant effect on all of the individual-tree characteristics examined, but its effect on per-hectare values was mixed. Although this report only provides short-term information on the effects of juvenile spacing on the growth and yield of lodgepole pine, it does indicate the need to optimize individual-tree growth rates with levels of growing stock to maximize yield per unit area. West. J. Appl. For. 20(3):160–166.


1987 ◽  
Vol 65 (1) ◽  
pp. 95-102 ◽  
Author(s):  
H. S. Whitney ◽  
R. J. Bandoni ◽  
F. Oberwinkler

A new basidiomycete, Entomocorticium dendroctoni Whitn., Band. & Oberw., gen. et sp. nov., is described and illustrated. This cryptic fungus intermingles with blue stain fungi and produces abundant essentially sessile basidiospores in the galleries and pupal chambers of the mountain pine bark beetle (Dendroctonus ponderosae Hopkins Coleoptera: Scolytidae) in lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.). The insect apparently disseminates the fungus. Experimentally, young partially insectary reared adult beetles fed E. dendroctoni produced 19% more eggs than beetles fed the blue stain fungi.


2001 ◽  
Vol 79 (11) ◽  
pp. 1349-1357 ◽  
Author(s):  
Cameron G Lait ◽  
Sarah L Bates ◽  
Karen K Morrissette ◽  
John H Borden ◽  
Allison R Kermode

Radiography is a valuable tool for assessing quality of conifer seeds, but it cannot differentiate between aborted seeds and seeds that have been emptied by western conifer seed bug (Leptoglossus occidentalis Heidemann) feeding. We tested three biochemical marker-based assays that were developed to identify L. occidentalis damage to seeds of Douglas-fir, Pseudostuga menziesii (Mirb.) Franco, for their use in lodgepole pine, Pinus contorta var. latifolia Engelmann. The three assays included measurement of storage protein reserve depletion, immunodetection of fragments of insoluble (crystalloid) storage proteins, and immunodetection of L. occidentalis salivary proteins. Aborted seeds contained significantly less soluble and insoluble protein than seeds that were fed on by L. occidentalis. Polyclonal antibodies raised against 11S globulin crystalloid proteins or L. occidentalis salivary gland extracts only immunoreacted with proteins in seeds exposed to L. occidentalis feeding. In a single-blind test, antibody raised against salivary-gland extracts correctly distinguished between undamaged full seeds, unfilled aborted seeds, and seeds fed on by L. occidentalis. Immunodetection of L. occidentalis salivary proteins was also performed on seeds of Abies amabilis Dougl. ex J. Forbes, Tsuga heterophylla (Raf.) Sarg., Picea sitchensis Bong (Carr.), Pinus ponderosa Lawson, and Pinus monticola Dougl. ex D. Don. For all species, immunoreactive polypeptides were only detected in seeds fed on by L. occidentalis. These biochemical marker-based techniques could help researchers and seed orchard managers estimate seed losses caused by L. occidentalis in commercial seed orchards and natural forest stands.Key words: Leptoglossus occidentalis, saliva, biochemical markers, polyclonal antibody, immunodetection, Pinus contorta.


2003 ◽  
Vol 33 (9) ◽  
pp. 1761-1771 ◽  
Author(s):  
R P Brockley ◽  
P Sanborn

The 6-year effects of differing levels of Sitka alder (Alnus viridus spp. sinuata (Regel) Á. Löve & D. Löve) retention (0, 500, 1000, and 2000 clumps/ha) on the development of retained alder and on the growth and foliar nutrition of 7-year-old naturally regenerated lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were evaluated in a sub-boreal ecosystem in the central interior of British Columbia. Alder development was inversely related to alder retention density, with the largest height and crown width increments occurring at the lowest alder densities. Low to moderate levels of alder cover did not significantly inhibit the diameter or height growth of lodgepole pine. Even under high alder cover, growth was not reduced until alder cover exceeded 45%. Over the 6-year response period, lodgepole pine diameter and height increments under high alder cover were reduced by 10% and 12%, respectively, relative to the no-alder treatment. The effect of alder density on lodgepole pine foliar N was strongly linear, with the highest N levels measured in the high alder retention treatment. However, the positive impact of alder retention on foliar N resulted in probable imbalance of N relative to S and possibly P and K. Unless alleviated, nutritional imbalances may preclude reliable assessment of the competitive effects (i.e., light and soil resources) of alder density, if any, on lodgepole pine growth.


2007 ◽  
Vol 37 (11) ◽  
pp. 2115-2129 ◽  
Author(s):  
R. P. Brockley

The effects of different regimes and frequencies of repeated fertilization (applied periodically and yearly) on the foliar nutrition and growth of young lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were investigated in central British Columbia. After 12 years, tree and stand growth responses indicated modest positive effects of two applications of nitrogen (N) and boron, with relatively large incremental gains to added sulphur and other nutrients (complete). Despite large increases in effective leaf area index and foliar N concentration relative to the control and periodic treatments, yearly applications of fertilizer were relatively ineffective in stimulating growth. When combined with frequent additions of other essential nutrients, annual fertilization with 50–100 kg N/ha over 12 years (825 kg N/ha in total) produced only slightly more “extra” wood than two applications of the multinutrient, complete fertilizer (400 kg N/ha in total) (19.4 m3/ha vs. 17.2 m3/ha, respectively). The most intensive fertilization treatment (1550 kg N/ha plus other nutrients over 12 years) produced shorter trees and less stand volume increment than periodic fertilization with the complete fertilizer. Treatment-induced changes in stand dynamics and growth allocation, disrupted foliar nutrient balance, and changes in soil biota and understory vegetation community structure may have negatively affected tree growth in intensively fertilized treatment plots.


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