A Comparison of Non-Linear and Linear Models for Describing Gallery Length Distribution of Dendroctonus frontalis Attacking Shortleaf Pine

by | Jun 16, 2022 | 1971-1980 Publications

Abstract

Non-linear and linear models were compared to determine how well they described the within tree distribution of egg gallery constructed by the southern pine beetle attacking short leaf pine. The model which resulted in the best description, i.e., smallest root mean squared error and highest R2, was y = a + bx + cx2 + d1 IBTm + d2R + d3A, where y is the gallery length per 100 cm2, x is the height of infestation, IBT m is the innerbark thickness at mid-bole, R is the ratio of infested bole length to tree height and A is representative of infested area computed by multiplying infested bole length by diam at breast height.

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NEBEKER, TE, RR HOCKING, OP HACKNEY, and JH LASHOMB. 1978. “COMPARISON OF NONLINEAR AND LINEAR-MODELS FOR DESCRIBING GALLERY LENGTH DISTRIBUTION OF DENDROCTONUS-FRONTALIS ATTACKING SHORTLEAF PINE.” Environmental Entomology7 (5): 636–40. https://doi.org/10.1093/ee/7.5.636.

Microflora from the Alimentary Tract of Healthy Southern Pine Beetles, Dendroctonus frontalis (Scolytidae), and Their Possible Relationship to Pathogenicity

by | Jun 16, 2022 | 1971-1980 Publications

Abstract

The microflora of healthy larvae and adults of the southern pine beetle, Dendroctonus frontalis, were determined by aseptically excising portions of the fore-, mid-, and hindguts and culturing them on agar. Aerobacter aerogenes, Alcaligenes jaecalis, and Serratia marcescens were the principal species of bacteria recovered, and Aspergillus spp. and Penicillium spp. were the principal genera of fungi. Seven of the species recovered were identical with facultative or conditioned pathogens recovered from diseased beetles in other studies.

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MOORE, GE. 1972. “MICROFLORA FROM ALIMENTARY-TRACT OF HEALTHY SOUTHERN PINE BEETLES, DENDROCTONUS FRONTALIS (SCOLYTIDAE), AND THEIR POSSIBLE RELATIONSHIP TO PATHOGENICITY.” Journal of Invertebrate Pathology19 (1): 72-. https://doi.org/10.1016/0022-2011(72)90191-7.

Estimating the Developmental Time of the Southern Pine Beetle Dendroctonus frontalis as a Function of Field Temperatures

by | Jun 16, 2022 | 1971-1980 Publications

Abstract

Three methods for estimating the field developmental time of the southern pine beetle were compared. The estimates by each of the 3 methods were found to agree at high temperatures. Depending on the season of the year and temperature extremes, Method I (1st appearance of a stage to the 1st appearance of the succeeding stage) over- or under-estimated the developmental time estimated by Method IT (date 50% of the population was observed in a stage to date 50% of the population was observed in the succeeding stage) and Method III (points where highest densities were observed in succeeding stages). The egg stage was found to last 8-27 days, the larval stage 10-62 days, and the pupal stage 7-26 days, depending upon mean temperature. The range of temperatures observed in the field was between 4° and 28°C.

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MIZELL, RF, and TE NEBEKER. 1978. “ESTIMATING DEVELOPMENTAL TIME OF SOUTHERN PINE BEETLE DENDROCTONUS-FRONTALIS AS A FUNCTION OF FIELD TEMPERATURES.” Environmental Entomology7 (4): 592–95. https://doi.org/10.1093/ee/7.4.592.

Comparison of Within-Tree Distributions and Population Estimation Procedures for Declining Populations of Dendroctonus frontalis Colonizing Loblolly and Shortleaf Pine

by | Jun 16, 2022 | 1971-1980 Publications

Abstract

This study was designed to determine if the within-tree distributions of various southern pine beetle (SPB) life stages were similar for declining populations infesting loblolly and shortleaf pine in North Carolina. A secondary objective was to compare the accuracy of within-tree population estimation procedures based on reduced sampling efforts. This study was based on 20 infested loblolly pine sampled from 1975-76 and 10 shortleaf pine sampled from 1976-77. Trees were intensively sampled using 10 sample heights/tree. Nonintensive sampling was simulated using a portion (3 heights/tree) of the intensive samples. Both graphical and statistical comparison of data showed that quite similar within-tree distributions occurred for all SPB life stages infesting both host species. Comparison of intensive and nonintensive within-tree population estimates showed that accurate results were obtained from the latter at a considerable reduction in time and effort.

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MCCLELLAND, WT, FP HAIN, and WD MAWBY. 1979. “COMPARISON OF WITHIN-TREE DISTRIBUTIONS AND POPULATION ESTIMATION PROCEDURES FOR DECLINING POPULATIONS OF DENDROCTONUS-FRONTALIS COLONIZING LOBLOLLY AND SHORTLEAF PINE (COLEOPTERA, SCOLYTIDAE).” Environmental Entomology8 (6): 1037–40. https://doi.org/10.1093/ee/8.6.1037.

Survival of Declining Dendroctonus frontalis Populations During a Severe and Nonsevere Winter

by | Jun 16, 2022 | 1971-1980 Publications

Abstract

Declining infestations of Dendroctonus frontalis were studied in terms of within-tree, within-spot, and within-area survival between a severe and mild winter. While brood survival differed dramatically between the 2 winters, the net effect on population trends was the same. Infestations in the study areas neither survived nor proliferated during the following spring and summer. During the severe winter of 1976-77 nearly 100% brood mortality occurred following a period of subfreezing temperatures and this was directly responsible for spot collapse. During the mild winter of 1975-76 survival was dependent on brood stage and location within the tree. Brood survival, which was comparable to that from the previous late summer and autumn, was not the cause of spot mortality. Periodic emergence during intermittent warm periods and a tendency to disperse combined with high dispersal losses were thought to be responsible.

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MCCLELLAND, WT, and FP HAIN. 1979. “SURVIVAL OF DECLINING DENDROCTONUS-FRONTALIS POPULATIONS DURING A SEVERE AND NONSEVERE WINTER (COLEOPTERA, SCOLYTIDAE).” Environmental Entomology8 (2): 231–35. https://doi.org/10.1093/ee/8.2.231.