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where bark beetles are relatively unimportant as pests. The bark beetles are more conspicuous in the higher latitudes, particularly in the coniferous forests of Mexico and Central America and the southern beech forests of Chile and Argentina.

Many species of Scolytidae are serious pests of trees, both hardwoods and conifers. The damage in tropical areas is caused by the staining of sapwood by fungal growths (more so by the ambrosia beetles than by bark beetles), in addition to physical destruction of the wood by the tunneling activities of both biological types. Injured or unthrifty trees and cut timber are most susceptible to attack, but some species infest living trees, mining the cambium and often girdling and killing major branches or the entire tree. Damage is often first noticed, particularly in conifers, when copious amounts of sap appear at the site of entry. Healthy trees are often able to ward off infestation by flooding out the colonizing beetles. The tops of affected trees often turn brown and wilt.

The burrows of Scolytidae are restricted largely to the phloem and are two-dimensional. They form varied geometrical patterns on the inside of the bark and on the surface of the sapwood, from simple straight or meandering lines to bira-mous, stellate, multiramous, or branching designs. Each pattern is usually characteristic of a species or genus and thus of value in identification. Platypodids burrow deep within the sapwood.

A widespread, very injurious ambrosia beetle is Platypus parallelus, which riddles logs left after cutting and prior to removal to the mill (Wood pers. comm.). In addition to attacking forest trees, scolytids are common pests of woody crops such as cacao (Xyleborus; fig. 9.11 g) and coffee (Hypothenemus hampei, broca do café, barrenador del café; fig. 9. llh) (Quezada and Urbina 1987).

The study of these beetles in Latin America is in an embryonic state (Atkinson and Equihua 1986, Haack et al. 1989, Martinez and Atkinson 1986). There are no comprehensive publications, although portions of the fauna have been described in monographs (Scolytidae in Wood 1982, Platypodidae in Schedl 1972). The fragmentary literature refers to somewhat more than 1,500 known scolytid and about 250 platypodid species. This may be no more than 50 percent of the actual total faunas of each family.

References

Atkinson, T. H., and E. Equihua. 1986. Biology of the Scolytidae and Platypodidae (Coleoptera) in a tropical deciduous forest at Chamela, Jalisco, Mexico. Fla. Entomol. 69-303-310.

Haack, R. A., R. F. Billings, and A. M. Richter. 1989. Life history parameters of bark beetles (Coleoptera: Scolytidae) attacking West Indian Pine in the Dominican Republic. Fla. Entomol. 72: 591-603. Martínez, A. E., and T. H. Atkinson. 1986. Annotated checklist of bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) associated with a tropical deciduous forest at Chamela, Jalisco, Mexico. Fla. Entomol. 69: 619-635. Quezada, J. R., and N. E. Urbina. 1987. La broca del fruto del cafeto, Hypothenemus hampei, y su control. In J. Pinochet, Plagas y enfermedades de carácter epidémico en cultivos frutales de la región Centroamericana. CATIE, Panama. Pp. 48-59. Schedl, K. E. 1972. Monographic der Familie Platypodidae Coleoptera. Junk, The Hague. Wood, S. L. 1982. The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. Great Basin Nat. Mem. 6: 1-1359.

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