Southern pine beetl

R=OH). With less polar chloride substituents, however, the RhuA dia-stereoselectivity is reduced and a considerable fraction of the FucA configurated product (40%) is also formed. Interestingly, alkaline cyclization in the latter occurs with an inverse preference to furnish 177, which contains the enantiomeric bicyclic [3.2.1] structure shared by the FruA product 175 as well as by (S)-( — )-frontalin 178, the aggregation pheromone of the southern pine beetle Dendroctonus frontalis. 

Is of serious concern. The role of chemical communication, in relation to proposed control tactics, of predators and bark beetles will be discussed. Emphasis will be on Thanaslmus dublus (F.) (Coleoptera Clerldae) and Medetera blstrlata Parent (Dlptera Dollchopodldae) which are primary predators of the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera Scolytidae). 

It is the intent of this paper to explore the various control tactics that are being suggested in the management of bark beetles in the forest system with specific attention given to the potential impact on the predator population. Similar arguments could be extended to other bark beetle mortality agents such as the parasite community. Primary examples and control tactics discussed will be drawn from our experience with the southern pine beetle, I). frontalis, a major pest in the southeastern U.S., along with other bark beetles in North America. 

Cut and Leave. This method was first recommended by the Texas Forest Service for controlling small southern pine beetle spots (10-15 infested trees) that could not be salvaged (5). As the treatment implies, trees are felled with the tops directed into the infested area rather than random felling. Mortality to the bark beetles is enhanced by the increased subcortical temperature resulting from direct exposure of the bark to the sun s rays and the inability of the immature stages to move to more protected areas, i.e. the under-surface of the felled trees. 

Pheromone Disruption and Inhibitors. Pheromones play an important role in the landing and attack behavior of bark beetles (9, 11, 12). Attractants orient flying beetles to a common host tree in high numbers over a relatively short time period. Two techniques have been recently developed to take advantage of the southern pine beetle response to pheromones. 

The first technique using pheromones to manipulate the southern pine beetle population relies on inhibition. Field bioassays have shown that aggregation of the southern pine beetle on attractant-baited traps can be significantly reduced by the... 

The second technique utilized frontalure which was placed as a bait on dead- or non-host trees in an attempt to suppress southern pine beetle spot growth (15). Since the technique employs chemical cues that the natural enemies utilize, i.e. kairomones in host location, it probably has little detrimental affect on the adult predators. However, the use of inhibitors and their impact on natural enemies is not known. The data base is lacking and we can only express concern. 

Brand J. M. and Barras S. J. (1977) The major volatile constituents of a basidiomycete associated with the southern pine beetle. Lloydia 40, 398 -00. 

Grosman D. M. (1996) Southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera Scolytidae) quantitative analysis of chiral semiochemicals. PhD thesis. Viginia Polytechnical Institute. 

Rudinsky J. A., Morgan M. E., Libbey L. M. and Putnam T. B. (1974) Antiaggregative-rivalry pheromone of the mountain pine beetle, and a new arrestant of the southern pine beetle. Environ. Entomol. 3, 90-98. 

What are some examples of these attractants (Figure 1) For mate finding, the insect-produced pheromones are the primary examples. However, environmental factors may also play an important role in the effectiveness of attractants. In the southern pine beetle, Dendroctonus frontalis. alpha-pinene released from an attacked tree is necessary along with the endogenously produced frontalin in order to attract males for mating (14). 

Stephen FM, Paine TD (1985) Seasonal patterns of host tree resistance to fungal associates of the southern pine beetle. Z Ang Ent 99 113-122... 

Frontalin (98, Figure 4.49) is the active component of the aggregation pheromone of the southern pine beetle (Dendroctonus frontalis), the western pine beetle (Dendroctonus brevicomis) and the Douglas-fir beetle (Dendroctonuspseudotsugae). Mori s 1975 synthesis of the enantiomers of frontalin via enantiomer separation (optical resolution) of an intermediate87 enabled their bioassay, and only (lS,5/ )-98 was bioactive as the pheromone component of D. brevicomis.32 A recent study on female D. frontalis revealed its (15, 5/C)-98 to be of about 91% ee.88... 

The bark from pines infested with the southern pine beetle attracts two species of parasitoids.171 If the compounds involved can be identified, they might be put on the pine trees at the first sign of a beetle. It might be necessary to augment the supply of parasitoids by releasing some reared in the laboratory. 

S.5R)-hrontalin -e Southern pine beetle (Dendroctonus frontalis) A Grubbs Olefin methatesis". Baker s yeasi1. 1I54J" 1168 h... 

This hypothesis is unvalidated at present, because these case studies employed different methods, are not replicated across genera, variability in natural enemies numbers is complex, and we caimot adequately separate cause and effect. Also, ratios of predators to prey are highly plastic within systems,and predation and competition are not independent owing to dilution effects. We also lack information on its applicability to other systems. Predaceous checkered beetles cause greater proportionate mortality to mountain pine beetle, Dendroctonus ponderosae Hopkins during endemic than eruptive conditions, which is consistent with our model, but not validating without information on the pre-attack chemistry of killed trees. Likewise, predation of southern pine beetle, Dendroctonus frontalis... 

LORIO, JR.P.L., HODGES, J.D., Tree water status affects induced southern pine beetle attack and brood production, USDA FS South. For. Exper. Stn. Res. Pap. SOUS, 1977. 

COOK, S.P., HAfN, F.P., Defensive mechanisms of loblolly and shortleaf pine against attack by southern pine beetle, Dendroctonus frontalis Zimmerman, and its fungal associate, Ceratocystis minor (Hedgecock) Hunt, J. Chem. Ecol, 1986, 12, 1397-1406. 

COYNE, J.F., LOTT, L.H., Toxicity of substances in pine oleoresin to southern pine beetles, J. Georg. Entomol. Soc., 1961,11, 301-305. 

STEPHEN, F.M., TAHA, H.A., Area-wide estimation of southern pine beetle populations. Environ. EntomoL, 1979,8, 850-855. 

SCHOWALTER, T.D., COULSON, R.N., CROSSLEY, D.A., Role of southern pine beetle Dendroctonus frontalis Zimmermann (Coleoptera, Scolytidae) and fire... 

MAWBY, W.D., MAIN, F.P., DOGGETT, C.A., Endemic and epidemic populations of southern pine beetle Implications of the two-phase model for forest managers. For. Sci., 1989,35, 1075-1087. 

TURCHIN, P., LORIO, P.L.JR., TAYLOR, A.D., BILLINGS, R.F., Why do populations of southern pine beetles (Coleoptera Scolytidae) fluctuate . Environ. Entomol, 1991,20, 401-409. 

THATCHER, R.C., SEARCY, J.L., COSTER, J.E., HERTEL, G.D., The Southern Pine Beetle. USDA FS Science and Education Administration Tech. Bull. 1631. USDA, Washington, DC, 1981, 267 pp.. 

KLEPZIG, K.D., FLORES-OTERO, J., HOFSTETTER, R.W., AYRES, M.P., Effects of available water on growth and competition of southern pine beetle associated fungi, Mycol. Res., 2004,108, 183-188. 

HODGES, J.D., ELAM, W.W., WATSON, W.F., NEBEKER, T.E., Oleoresin characteristics and susceptibility of four southern pines to southern pine beetle (Coleoptera Scolytidae) attacks. Can. Entomol, 1979, 111, 889-896. 

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