Aerial Application of Ethephon is ineffective in Controlling Lodgepole Pine Dwarf Mistletoe

1989 ◽  
Vol 4 (1) ◽  
pp. 27-28 ◽  
Author(s):  
Kathryn Robbins ◽  
David W. Johnson ◽  
Frank G. Hawksworth ◽  
Thomas H. Nicholls
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Direct Contact ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Aerial Application ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum

Abstract Ethephon is an ethylene-releasing plant growth regulator that induces abscission of dwarf mistletoe (Arceuthobium americanum) aerial shoots on lodgepole pine (Pinus contorta) when applied from the ground. However, ethephon was not effective when applied by helicopter in two Colorado tests, because it did not come into enough direct contact with dwarf mistletoe shoots to induce abscission. West. J. Appl. For. 4(1):27-28, January 1989.

The effects of male and female Arceuthobium americanum (lodgepole pine dwarf mistletoe) infection on the relative positioning of vascular bundles, starch distribution, and starch content in Pinus contorta var. latifolia (lodgepole pine) needles

Botany ◽  
2008 ◽  
Vol 86 (5) ◽  
pp. 539-543 ◽  
Author(s):  
Aditya Chhikara ◽  
Cynthia M. Ross Friedman
Keyword(s):  
Pinus Contorta ◽  
Biochemical Analysis ◽  
Lodgepole Pine ◽  
Starch Content ◽  
Periodic Acid ◽  
Vascular Bundles ◽  
Dwarf Mistletoe ◽  
Needle Anatomy ◽  
Arceuthobium Americanum

The lodgepole pine dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., is a dioecious angiosperm that parasitizes conifers in western Canadian forests, causing significant yearly timber loss. A striking consequence of dwarf mistletoe infection is a marked reduction in the size of the needles located distal to the infection. The purpose of this work was to use microscopy, cytochemistry, and biochemical analysis to determine whether this reduction was associated with changes in needle anatomy and (or) starch content. Furthermore, we wanted to investigate whether these potential changes were affected by the gender of the infecting dwarf mistletoe plant. We developed a ratio (R) that evaluated the position of the two vascular bundles relative to the size of the needle, and found that bundles from male-infected trees were positioned significantly closer together than in needles from female-infected or uninfected trees (p < 0.05). Using the periodic acid – Schiff’s (PAS) reaction for cytochemical identification of starch in situ, we determined that needles from uninfected trees had abundant starch grains compared with needles from infected trees; colourimetric analysis for total starch content corroborated our PAS data. This is the first report of this phenomenon in lodgepole pine, and further supports the use of needle characteristics to assess tree health.

Relationships between dwarf mistletoe and the canopy structure of an old-growth lodgepole pine forest in central Oregon

2003 ◽  
Vol 33 (6) ◽  
pp. 997-1009 ◽  
Author(s):  
R C Godfree ◽  
R O Tinnin ◽  
R B Forbes
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Abiotic Factors ◽  
Canopy Structure ◽  
Structural Diversity ◽  
Conifer Forest ◽  
Dwarf Mistletoe ◽  
Arceuthobium Americanum ◽  
Canopy Volume ◽  
The Vertical Distribution

The relationships between abundance of dwarf mistletoe (Arceuthobium americanum Nutt.) and the canopy structure of stands of lodgepole pine (Pinus contorta var. murrayana (Grev. & Balf.) Engelm.) were investigated in the central Oregon pumice zone. Foliage height profiles were generated for stands containing light, moderate, and heavy infestations of A. americanum, and the vertical distribution of P. contorta foliage was modeled using the Weibull distribution. Stand-level changes in the Weibull parameters σ (scale parameter) and c (shape parameter) as well as other canopy indices were related to the abundance of A. americanum, the density of competing tree species, and stand-level abiotic factors. Foliage intercept diagrams showed that heavily infested stands had more foliage in the lower canopy and less in the upper canopy than lightly infested stands, but that total canopy height and canopy volume were similar regardless of infestation level. We also found that dwarf mistletoe abundance was strongly related to σ (r = –0.74, p < 0.001) and c (r = –0.54, p < 0.0001). Since heavily infested stands contained fewer large but many more small P. contorta than lightly infested stands, we conclude that A. americanum causes the canopy of infested stands to change, in part, by inducing demographic changes in populations of the host tree. These results illustrate the significant effects that dwarf mistletoes can have on the structural diversity of conifer forest communities and have important consequences for the conservation and management of these systems.

Influence of plant growth regulator and rhizobial inoculation on nodulation and soybean nitrogen contant

2007 ◽  
Vol 35 (2) ◽  
pp. 993-996 ◽  
Author(s):  
Sulejman Redžepović ◽  
Sanja Sikora ◽  
Josip Čolo ◽  
Mihaela Blažinkov ◽  
Marija Pecina
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Rhizobial Inoculation
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