Adhesives for seed placement during artificial inoculation of Pinus banksiana seedlings with the dwarf mistletoe Arceuthobium americanum

2003 ◽  
Vol 81 (10) ◽  
pp. 1039-1043 ◽  
Author(s):  
J P Brandt ◽  
Y Hiratsuka ◽  
D J Pluth

Lodgepole pine dwarf mistletoe (Arceuthobium americanum Nutt. ex Engelm.) is a serious pest of jack pine (Pinus banksiana Lamb.). Research investigating factors such as host resistance, influence of host nutrition on infection rates, and effect of temperature and humidity on the life cycle of the pathogen is limited by our ability to consistently infect the host through artificial means. A greenhouse experiment utilizing a completely randomized design with four replicates was conducted to test the effectiveness of three chemical compounds and the natural viscin of the dwarf mistletoe seed to act as adhesives during artificial inoculation of jack pine seedlings. Synthetic adhesives used were anhydrous lanolin (LAN), hydroxypropylcellulose (HPC), and polyvinyl acetate (PVA). The percentage of infected seedlings was significantly higher with HPC compared with that of PVA, LAN, and the seed's viscin. HPC, as the superior adhesive, and the techniques described should allow consistent production of seedlings infected with dwarf mistletoe for research, regardless of the dwarf mistletoe species involved. Problems encountered during the testing of the adhesives are discussed in relation to the nature of the adhesives and their application.Key words: anhydrous lanolin, hydroxypropylcellulose, polyvinyl acetate, viscin.

2004 ◽  
Vol 118 (4) ◽  
pp. 595 ◽  
Author(s):  
Brock Epp ◽  
Jacques C. Tardif

The Lodgepole Pine Dwarf Mistletoe (Arceuthobium americanum Nutt. ex Engelm.) is an important pathogen of Jack Pine (Pinus banksiana Lamb.). Dwarf Mistletoe alters tree form, suppresses growth, and reduces volume and overall wood quality of its host. Stem analysis and a 3-parameter logistic regression model were used to compare the growth of heavily and lightly to non infected Jack Pine trees. At the time of sampling, no significant reduction in diameter at breast height and basal area were observed in heavily infected trees. However, a significant reduction in height and volume and an increase in taper were observed in heavily infected trees. Growth models predicted a 21.1% lower basal area, 23.4% lower height and 42.1% lower volume by age 60 for the high infection group.


2004 ◽  
Vol 34 (1) ◽  
pp. 174-183 ◽  
Author(s):  
J P Brandt ◽  
Y Hiratsuka ◽  
D J Pluth

Lodgepole pine dwarf mistletoe (Arceuthobium americanum Nutt. ex Engelm.) is one of the most damaging pathogens of jack pine (Pinus banksiana Lamb.) in western Canada. Jack pine forests in the colder, more northerly areas, however, are free of dwarf mistletoe, suggesting that the pathogen is limited by low temperature. The effect of extreme cold temperatures on germination rates of overwintering dwarf mistletoe seeds and survival of dwarf mistletoe germinants was evaluated. Germinative ability of overwintering seeds increased with increasing temperatures between –39 and –35 °C, regardless of seed source. Exposure period also strongly influenced germination rates. Exposure to temperatures near –38, –46, or –53 °C for 96 or 144 h was almost always lethal. At –37 °C, germination was greater after 48 h than after 96 h, although it was still significantly lower than in the controls. Temperatures down to –6 °C in late spring did not reduce germinant survival. Overall, these results may explain the absence of dwarf mistletoe from northern areas commonly exposed to periods in winter with minimum temperatures below about –40 °C. These areas are potentially at risk from the pathogen if the climate of Canada's northern interior continues to warm as it has over the last several decades.


2006 ◽  
Vol 36 (4) ◽  
pp. 1006-1016 ◽  
Author(s):  
J P Brandt

While lodgepole pine dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., is one of the most damaging pests of jack pine (Pinus banksiana Lamb.) in western Canada, no studies have examined the life cycle of this parasite in this pathosystem. Twenty-five jack pine trees in a plantation in Edmonton, Alberta, were inoculated with seeds of A. americanum in the fall of 1998 and 1999; these inoculants were monitored until the dwarf mistletoe plants that arose completed their life cycle. Ninety-two percent of inoculated seeds overwintered on their host. Seventy percent of these seeds germinated, mostly in May. Of these germinants, 69% developed holdfasts. Sixty-eight percent of germinants that developed holdfasts infected their host and produced shoots, primarily between July and August in the second season after inoculation. Of the 56 plants that developed from the 175 inoculations, 34 were pistillate plants and 19 were staminate plants, and 3 immature plants died because the host branch died. Pistillate plants flowered significantly earlier than staminate plants (4.1 vs. 4.7 years). Most pistillate plants produced seed in the fifth year, although one plant produced seed in 4 years. Thus, A. americanum probably has a 5-year life cycle on jack pine.


2001 ◽  
Vol 79 (5) ◽  
pp. 521-527
Author(s):  
D E Robinson ◽  
D Punter

The purpose of this study was to test the hypothesis that infection of jack pine (Pinus banksiana Lamb.) by jack pine dwarf mistletoe (Arceuthobium americanum Nutt. ex Engelm.) increases with increasing tree age and decreases with increasing tissue age. One-, 2-, and 3-year-old tissues of 3-, 5-, and 7- year-old jack pines and 1-, 4- and 8-year-old tissues of 12-, 17-, and 22-year-old jack pines in Belair Provincial Forest were inoculated with seed of A. americanum in September of 1992 (year 1) and 1993 (year 2). Overwinter and postwinter seed removal, fungal and insect damage, and infection success were monitored from the time of inoculation to harvesting of inoculated branches. In years 1 and 2, overwinter seed displacement was 12.2 and 30.6%, while postwinter loss was 28.8 and 22.2%, respectively. Seed germination ranged from 14.3 to 38.1% and from 3.1 to 17.5%, respectively, in years 1 and 2. Infection success varied from 2.0 to 35.0% (year 1) and from 0.0 to 13.0% (year 2). Lower mean daily temperatures in January and February (p < 0.001) were hypothesized to have killed more seeds and thereby reduced infection success in year 2. Infection success did not increase with increasing tree age (year 1: p = 0.188; year 2: p = 0.807) in either year of the study. Infection success increased with increasing tissue age in year 1 (p < 0.001) but not in year 2 (p = 0.358). We rejected the hypotheses that susceptibility to infection by A. americanum increases with increasing tree age or decreases with increasing tissue age of jack pine. Infection success appears to be primarily dependent upon seed displacement caused by wind, snow, or rain.Key words: jack pine, dwarf mistletoe, infectivity, juvenile resistance, seed displacement.


1991 ◽  
Vol 69 (3) ◽  
pp. 685-688 ◽  
Author(s):  
Jeannie Gilbert ◽  
David Punter

Pollen of Arceuthobium americanum Nuttall ex Engelmann, a parasitic dwarf mistletoe of Pinus banksiana Lamb, in Manitoba, was germinated on media containing a range of concentrations of sucrose and salts. Highest germination levels occurred on 20% sucrose agar; addition of salts significantly depressed germination. Pollen germinability was below 5% at first but increased to near 50% as the season advanced. Mean germination differed significantly between flowers from 10 staminate plants but peaked at approximately the same times in association with increasing temperatures. Freezing night temperatures were followed by reduced germinability. The optimum temperature for in vitro pollen germination is close to 30 °C, whereas 40 °C impairs germination. Key words: parasitic angiosperms, microclimate, jack pine, reproductive biology.


1971 ◽  
Vol 49 (4) ◽  
pp. 501-504 ◽  
Author(s):  
F. H. Tainter ◽  
D. W. French

Formation of wound periderm appears to be a common form of resistance reaction in the Arceuthobium pusillum – Larix laricina combination, based on previous observations and an extensive examination of two witches' brooms of this host. Not only is wound periderm common in spur shoots within witches' brooms, but it also apparently restricts the development of the endophytic system in branchlets composing witches' brooms. Branchlets within witches' brooms of Pinus banksiana infected with A. pusillum and A. americanum also produced wound periderm similar to that described in eastern larch, which may account for the relative scarcity of aerial shoots on this host and restricted development of the endophytic system.


2007 ◽  
Vol 85 (3) ◽  
pp. 307-315 ◽  
Author(s):  
Adrianne V. Rice ◽  
Markus N. Thormann ◽  
David W. Langor

Mountain pine beetles ( Dendroctonus ponderosae Hopkins; (MPB)) have spread into lodgepole × jack pine hybrid ( Pinus contorta Douglas × Pinus banksiana Lambert) forests in Alberta and are predicted to spread into jack pine forests. Their success in these forests is uncertain but will be influenced by multiple factors, including the ability of their associated blue-stain fungi to colonize the trees and the health of the encountered trees. Healthy and dwarf mistletoe infected pines at three sites across Alberta (one site per pine species) were inoculated with three isolates each of Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield and Ophiostoma montium (Rumbold) von Arx. Both fungi grew and caused lesions on all hosts, suggesting that MPB will not be limited by a lack of fungal growth. Both fungi caused longer lesions in jack and hybrid pines than in lodgepole pines, indicating that susceptibility varies among hosts and is greater in the novel systems than in the co-evolved one. G. clavigera caused longer lesions than O. montium in hybrids and lodgepole pines, while the two species caused similar-sized lesions on jack pine. Intraspecific variation was high in G. clavigera, with one isolate producing much shorter lesions than the other two. Dwarf mistletoe infestation had little effect on infection lesion length.


2005 ◽  
Vol 35 (8) ◽  
pp. 1914-1930 ◽  
Author(s):  
J P Brandt ◽  
Y Hiratsuka ◽  
D J Pluth

Information on the establishment of Arceuthobium americanum Nutt. ex Engelm. on its host, jack pine (Pinus banksiana Lamb.), is required to improve knowledge of this critical development stage and improve pest management. Laboratory and field observations on four populations of A. americanum seeds from Alberta collected in 2000 and 2001 and histological observations on one population were used to determine the timing and histopathology of parasite establishment on jack pine. Seed germination remained near zero until 110 d after placing seeds in storage; germination peaked after 230 d in 2001 and between 230 and 320 d in 2002. Interannual variation in germination timing at study sites was high. Interannual variation in percentage of germination was low, as was variation in percentage of germination from different seed sources. Germinated seeds of each seed source were significantly larger (48%) than seeds that did not germinate. Penetration at the base of spur shoots began during June–August and usually continued until June–July of the next year. The odds of infection when the germinant survived until the second growing season were 26–55 times greater than the odds of infection when the germinant withered in the first growing season. Symptoms of infection usually occurred 13–15 months after germination and were consistent for all seed sources and sites.


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