Insects Associated with Second-Year Ponderosa Pine Cones, Larimer and Boulder Counties, Colorado

1981 ◽  
Vol 26 (4) ◽  
pp. 375 ◽  
Author(s):  
Judy Bodenham ◽  
Robert E. Stevens
1976 ◽  
Vol 108 (7) ◽  
pp. 693-699 ◽  
Author(s):  
Judy Bodenham ◽  
Robert E. Stevens ◽  
T. O. Thatcher

AbstractConotrachelus neomexicanus Fall occurs throughout the range of Pinus ponderosa Laws. in the central and southwestern United States. It is commonly found infesting ponderosa pine cones in north-central Colorado. C. neomexicanus is univoltine. Eggs are laid in second-year cones from May through July. Larvae mine extensively in the cones and drop to the ground for pupation in the soil. Adults emerge from the soil in late summer and early fall, return to the trees to feed on twigs, and presumably hibernate in sheltered locations during the winter A tachinid fly, Myiophasia sp. nr. ruficornis Tns., is an internal parasitoid of weevil larvae.


1967 ◽  
Vol 99 (3) ◽  
pp. 264-267 ◽  
Author(s):  
A. F. Hedlin

AbstractThe pine seedworm, Laspeyresia piperana (Kft.), is a common pest in cones of Pinus ponderosa Laws. in British Columbia and may destroy up to 50% of the seed.Moths emerge in May, mate, and lay eggs on second-year pine cones. Immediately after hatching, the larvae migrate to the centre of the cone and feed on seeds throughout the summer. In autumn, larvae tunnel into the cone axis to overwinter. Pupation occurs in spring.


1956 ◽  
Vol 34 (1) ◽  
pp. 27-36 ◽  
Author(s):  
L. A. Lyons

The seed capacity of red pine cones varies from about 30 to over 110, depending on the size of the cone and its position in the tree crown, and is determined by the number of ovules that are structurally complete at the time of pollination. These ovules occur in a central "productive" region and constitute less than one-half of the total. The remaining ovules, most: of which are in the proximal part of the cone, never become structurally perfect, and do not contribute to seed production. Abortion of ovules in the productive region usually reduces seed production efficiency to 50–60%, and is accompanied mainly by withering of the nucellus in the first year and failure to produce archegonia early in the second year. The extent of ovule abortion during the first year varies indirectly with cone size, seed capacity, and height in tree.


2003 ◽  
Vol 33 (5) ◽  
pp. 870-884 ◽  
Author(s):  
Rick G Kelsey ◽  
Gladwin Joseph

Sixteen days after a September wildfire, ethanol and water were measured in phloem and sapwood at breast height and the base of Pinus ponderosa Dougl. ex P. & C. Laws. with zero (control), moderate, heavy, and severe crown scorch. The quantity of ethanol increased with each level of injury, resulting in trees with severe scorch containing 15 and 53 times more phloem and sapwood ethanol, respectively, than controls. Ethanol concentrations in the sapwood and adjacent phloem were related, probably as a result of diffusion. Upward movement in xylem sap was most likely responsible for the relationship between sapwood ethanol concentrations at breast height and the stem base. As trees recovered from their heat injuries, the ethanol concentrations declined. In contrast, ethanol accumulated in dead trees that lost their entire crowns in the fire. Various bark and xylophagous beetles landed in greater numbers on fire-damaged trees than on controls the following spring and summer, suggesting that ethanol was being released to the atmosphere and influencing beetle behavior. Beetle landing was more strongly related to sapwood ethanol concentrations the previous September than in May. Sapwood ethanol measured 16 days after the fire was the best predictor of second-year mortality for trees with heavy and severe crown scorch.


1993 ◽  
Vol 23 (8) ◽  
pp. 1507-1513 ◽  
Author(s):  
John M. Randall ◽  
Marcel Rejmánek

The biennial thistle Cirsiumvulgare (Savi) Tenore significantly reduced ponderosa pine (Pinusponderosa Dougl. ex Laws.) seedling growth during the second year of infestation but had insignificant effects in the first year when all thistles were in the rosette stage. Pine stem diameter relative growth rate was significantly negatively correlated with four different indices of thistle interference and with visual estimates of thistle cover. Total thistle density (adults + rosettes) within 2.0 m of target seedlings best explained differences in stem relative growth rate, but density of adults alone and visual estimates of thistle cover were nearly as good. Simple regressions indicated that soil moisture and pine predawn leaf water potential were significantly negatively correlated with thistle density and significantly positively correlated with stem relative growth rate, but multiple regressions and path analyses indicated that their effects on seedling growth were negligible relative to the other (unexplained) effects of thistle density. Foliar nitrogen, phosphorus, and potassium concentrations were not significantly correlated with thistle density and failed to explain differences in seedling growth. Although it remains unclear how thistles suppressed pine seedling growth, if these results hold true at other sites, plantation managers will have at their disposal relatively easy methods for assessing thistle interference.


2010 ◽  
Vol 171 (3) ◽  
pp. 293-302 ◽  
Author(s):  
Ken Keefover‐Ring ◽  
Yan B. Linhart
Keyword(s):  

1985 ◽  
Author(s):  
J.M. Schmid ◽  
S.A. Mata ◽  
J.C. Mitchell
Keyword(s):  

1986 ◽  
Vol 13 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Wayne T. Williams ◽  
JoAnne Ackermann Williams

More than 485,000 hectares of the Ponderosa Pine forests in the southern Sierra Nevada of California are diseased as a result of air pollution, while approximately 25% of the area of Sequoia-Kings Canyon National Park receives enough oxidant air-pollution to elicit symptoms of smog injury on Ponderosa Pine, the dominant mid-elevation tree.In 1983 we re-examined four permanent study plots that had been established in 1974–75. Smog symptoms on current needles in 1983 occurred on 23.8% of the trees compared with 14.5% only in 1975. Second-year needles had 60.7% showing symptoms compared with 44.2% in 1975. Less than 0.5% of the trees retained 6-years-old needles, and 21% had only 2 years of needle retention. Mortality attributed to air pollution was observed.


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