Environmental Entomology (1993) 22, 948-957

James P. Dunn and Peter L. Lorio Jr. (1993)
Modified water regimes affect photosynthesis, xylem water potential, cambial growth, and resistance of juvenile Pinus taeda L. to Dendroctonus frontalis (Coleoptera: Scolytidae)
Environmental Entomology 22 (5), 948-957
Abstract: We modified soil water supply to two groups of juvenile loblolly pines, Pinus taeda L., by sheltering or irrigating root systems in early summer or in late summer and measured oleoresin flow (primary defense), net photosynthesis, xylem water potential, and cambial growth throughout the growing season. When consistent significant differences in oleoresin flow and water potentials were detected between treatments, we induced attack by the southern pine beetle, Dendroctonus frontalis Zimmermann. Compared with irrigated trees, sheltered trees had lower xylem water potentials, reduced cambial growth, reduced photosynthesis, and reduced resin flow. In terms of response to beetle attack, sheltered trees had fewer attacks and less total gallery constructed, but those beetles that did attack sheltered trees were more successful (50-100% more eggs per attacking pair). However, the success of attacking beetles was generally very low, even in sheltered trees (only three to eight eggs per attacking pair). This performance, along with water deficits that strongly affected tree physiology, growth, and development, indicates that juvenile loblolly pine can make internal adjustments that limit the success of southern pine beetle attack.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Dendroctonus frontalis	Pine (Pinus)