Evolutionary biology has no practical application!
Actually, evolutionary biology has rather a lot of practical
applications. A recent article by Douglas Futuyma in Science 
listed several of these (mostly paraphrased or quoted from the
 Futuyma, D. 1995. The uses of evolutionary biology. Science
267(6 Jan. 1995):41-42.
- Biodiversity and conservation: Analysis of risk of extinction due
to "inbreeding, reduced gene flow, specialization, and constraints on
genetic and ecological responses to global change." 
- Phenotypic expression in novel environments: use of tools already
in used in studies of natural systems, like "molecular markers of gene
flow, gene geneaologies as evidence of gene exchange, analyses of
phenotypic plasticity, and the 'costs' of adaptation".
- Novel processes and products: This includes production of
antibiotics, flavors, pigments, biopolymers, and enzymes.
- Bioremediation: production of tolerance to waste products,
production of bacterial strains to decompose hazardous materials. 
- Wildlife management: identification of stocks by genetic analysis.
- Agriculture: identification of disease resistance factors in related
wild plants, pesticide resistance, management of pest adaptation to
pesticide, pest resistant cultivation. [4, 5]
- Health sciences: causes of senescence, treatment of fever, tracing
origins of pathogens, evolution of virulence in viruses and other
pathogens, measurement of genetic diversity in pathogens and in hosts,
mechanisms of drug resistance, evolutionary epidemiology.
 Kingsolver, J., P. Kareiva, and R.B. Huey, eds. 1993. Biotic
Interactions and Global Change. Sinauer: Sunderland, MA.
 Antonovics, J. 1975. Proceedings of the International Conference
on Heavy Metals in the Environment (Toronto 1975), pp.169-186.
 Gould, F. 1991. American Scientist 79:496.
- Georghiou, G.P. and T. Saito, eds. 1983. Pest Resistance to
Pesticides. Plenum: New York.