Insects Affecting Seed Production in Red Pine: II. Dioryctria disclusa Heinrich, D. abietella (D. and S.), and D. cambiicola (Dyar) (Lepidoptera: Phycitidae)

1957 ◽  
Vol 89 (2) ◽  
pp. 70-79 ◽  
Author(s):  
L. A. Lyons

This paper describes the seasonal history and habits of three borers of the genus Dioryctria that destroy red pine cones in Ontario. These insects, as a group, generally rank second in importance as cone destroyers to the cone beetle, Conophthorus resinosae Hopk., which was the subject of the first paper in this series (11), and are presented together because of their family relationship and the similarity of their habits.

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.


1971 ◽  
Vol 103 (4) ◽  
pp. 617-621 ◽  
Author(s):  
William J. Mattson

AbstractAnnual cone abundance and insect damage to cones are highly variable in red pine seed-production areas. Cone crop size fluctuates almost unpredictably from year to year, but the number of insect-attacked cones tends to increase annually unless limited by cone abundance. Sixty-six per cent of the variation in cone damage can be associated with variations in cone abundance. This information, coupled with the fact that red pine cone insects are almost entirely dependent on red pine cones for food, implies that crop size is highly important in regulating populations of cone insects. Insects will be most devastating in areas where crop size varies little from year to year.


1957 ◽  
Vol 89 (4) ◽  
pp. 150-164 ◽  
Author(s):  
L. A. Lyons

This paper describes the seasonal history and habits of the less important red pine cone insects, and presents notes on the predators, scavengers, and other insects that commonly inhabit infested cones. During 1950-1954, Eucosma monitorana Hein., Laspeyresia toreuta Groté, and Rubsaamenia sp. were rarely as abundant as the cone beetle, Conophthorus resinosae Hopk., (10) or Dioryctria spp. (11), although they contributed significantly to seed loss. Owing to the scarcity of these insects, some of the life history details remain incomplete.


1957 ◽  
Vol 89 (6) ◽  
pp. 264-271 ◽  
Author(s):  
L. A. Lyons

The broad study of factors responsible for poor seed production by red pines (Pinus resinosae Ait.) in central and southern Ontario has been concerned with the seed production capacity and efficiency of sound cones (1) and the description, life history, behaviour, and natural control of cone-inhabiting insects (2, 3, 4). The present contribution, which concludes the four-part series on red pine cone insects, deals with the time and duration of cone attack by the various insect species and the variability in the intensity of cone damage from year to year and from one locality to another. As an aid to the field diagnosis of the cause of cone damage, keys based on the appearance of mature larvae and injured cones are included.


2008 ◽  
Vol 43 (No. 4) ◽  
pp. 135-143 ◽  
Author(s):  
V. Kůdela

In ornamental gardening, <I>Spiraea × vanhouttei</I> is a frequently planted spirea species in the Czech Republic. In 2003, there arose a suspicion of possible occurrence of fire blight caused by <I>Erwinia amylovora</I> on spirea shrubs in Prague and its environs. This suspicion was disproved for a certainty. The absence of the fire blight pathogen in symptomatic spirea plants stimulates a further effort to tackle the problem of a cause of conspicuous fire blight-like symptoms or inflorescence blast occurring on some spirea shrubs. The subject of this paper is: (i) to describe symptoms, incidence and severity of inflorescence blast, bud and flower abnormalities occurring in <I>Spiraea × vanhouttei</I> shrubs; (ii) to find out differences in the occurrence of blasted inflorescences between <I>Spiraea</I> species and cultivars with the intention of verifying the hypothesis that the blast inflorescence and sterility of some spirea species are associated with hybrid species. Symptoms of inflorescence blast are every growing season. No seed is produced by blasted inflorescences. Besides inflorescence blast, aborted floral buds appeared sporadically on a small scale. Spirea species were split into four categories according to the incidence of blasted inflorescences. Out of 52 species evaluated, 10% showed no or scarce incidence, 52% medium incidence, 27% high incidence and 11% very high incidence. The scarce incidence of blasted inflorescences was connected with the high seed production. And vice versa, very high incidence of blighted inflorescences was closely connected with no or low seed production or with high incidence of sterility. Fifteen out of the evaluated spirea species are the result of hybridization. These hybrids occur in each of the four categories of spirea species distinguished by the incidence of blasted inflorescence. However, it is remarkable that the highest incidence of hybrid spireas occurs in the category with the highest incidence of blasted inflorescence (83.33%). In the remaining three categories of spirea species, the proportion of hybrids ranged from 18 to 21%. It might indicate some connection of spirea hybrids with sterility.


1992 ◽  
Vol 124 (1) ◽  
pp. 189-199 ◽  
Author(s):  
Peter de Groot ◽  
George T. Harvey ◽  
Pat M. Roden

AbstractGenetic divergence among populations of cone beetles, Conophthorus banksianae McPherson, C. coniperda (Schwarz), and C. resinosae Hopkins, was assessed by isozyme electrophoretic data. All but one of the eight loci examined were polymorphic, and one locus (Pgi) was sex-linked for C. coniperda. Genotype frequencies generally met Hardy-Weinberg expectations, and fixation index (FST) values indicated low-to-moderate genetic differences among conspecific populations. Fixed allele differences were detected at two loci, Pgi and Dia-2, which separated C. resinosae from C. coniperda, and thus confirmed their specific status established previously by morphological, karyological, and other biochemical characters. Electrophoretic data strongly suggested C. coniperda does not attack red pine cones, and C. resinosae does not attack white pine cones. No diagnostic loci were found to separate C. resinosae from C. banksianae. Phenetic clustering and pairwise comparisons of genetic distance coefficients indicated very little genetic divergence between C. resinosae and C. banksianae. These data were interpreted as failing to reject the null hypothesis that C. resinosae and C. banksianae are one species, an interpretation consistent with available taxonomic evidence from ecological, karyological, and other biochemical characters.


1982 ◽  
Vol 114 (11) ◽  
pp. 1069-1076 ◽  
Author(s):  
Akira Mutuura

AbstractDioryctria resinosella, a species feeding on red pine cones or shoots, is described as new and recorded from Maine, southern Ontario, Wisconsin, and Minnesota. The new species is distinguished from D. zimmermani (Grote) and D. banksiella Mutuura & Munroe by the differences in wing markings, genitalia characters, and ecological aspects.


1988 ◽  
Vol 64 (6) ◽  
pp. 480-484 ◽  
Author(s):  
W. M. Stiell

A plantation of red pine (Pinus resinosa Ait.) produced heavy cone crops in 1970 and 1984. Established at 6.5 × 6.5 m, the stand was 18-years old in 1970 and still open-grown; crowns were closed before 1984. Cone production at the two dates was compared for 28 trees. While total production was similar for 1970 and 1984, distribution within the sample differed. Although 18% of the trees maintained their rank in 1984, some large changes in production ranking took place from one crop to the next. Despite a tendency at both dates for crop size to increase with current dbh, exceptions were evident and the largest trees did not necessarily bear the most cones. Crop size in 1970 was the variable most closely associate with 1984 crop size and was significantly correlated with it independently 1984 dbh. High cone production did not seem to depress tree growth, based on a comparison of 1970-72 basal area increment of more versus less prolific cone bearers. Before a stand has borne its first good cone crop, expectations for highest yields would have to be based on tree size. For subsequent crops, previous production by individuals would be the best guide. The two top cone bearers far surpassed all others in both crop years and would be the first individuals selected for seed trees in a seed production area.


1931 ◽  
Vol 63 (6) ◽  
pp. 126-127
Author(s):  
E. B. Watson

This bark-beetle is locally distributed over the forested areas of Quebec and Ontario, extending westward into Manitoba; in the United States, it has been recorded from Wisconsin and Michigan.The insect has been found breeding in fallen white pine and jack pine, and, within recent years, has also been recorded from red pine.


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