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It is unfortunate there are not more sustainable, environmentally acceptable con- 

 trols available for exotic pests. The prevailing mind set has been to eradicate exotics 

 with chemical warfare for over half a century. It is only recently that budgetary con- 

 straints have begun to impact all government programs raising Questions as to their 

 cost and effectiveness. These questions may bring about the climate necessary to 

 foster alternative controls for exotics. 



Although there were very successful biological control approaches for exotic pests 

 in the past, little has been done for the past 2 decades. Such long-term, sustainable 

 solutions require an investment today before we can expect payoffs in the future. 

 Successful weed biological control projects take 8 to 10 years from inception. With- 

 out an investment, the solutions wul never be available. 



A practice such as biological control which encourages the introduction of yet 

 more exotic organisms, even though they are beneficial, is a legitimate concern. The 

 introduction of any exotic organism should be attempted only with great diligence 

 and caution and only by specialists who have training in the conduct of biological 

 control. 



Biological control is not a solution for every pest situation, and it should be used 

 only where appropriate. Biological control has provided the most spectacular, target- 

 specific, and self-perpetuating control of some of our most injurious exotic species. 

 It is especially appropriate for use against pests in managed ecosystems for which 

 chemici controls and chemical eradication programs pose great threat or where, in 

 many cases, these approaches are not economically or operationally feasible. 



Increased concern 



Commerce and Transport. Today's tourism and commerce is contributing to a con- 

 tinual movement of biota, plants, vertebrates, insects, bacteria, fungi, viruses, and 

 others, around the globe. In 1988, there were over 32,000 interceptions of organisms 

 in luggage and market products at U.S. borders by the USDA Animal and Plant 

 Health Inspection Service. Best estimates are that these interceptions represent less 

 that 50% of the biota being introduced inadvertently or purposefully. Containerized 

 cargo on ships, trains, trucks, and planes, the rapid movement of cargo among these 

 modes of transportation, and other changes in transport methods make it easier and 

 cheaper to transport goods in a global economy. However, these changes make it 

 even easier for exotic organisms to survive transit from one region to another. These 

 changes in transport methods also make it more difficult to intercept exotic biota 

 with governmental interdiction programs, since ports of entry no longer are coastal 

 and centralized, but distributed inland and dispersed to where they are convenient 

 to commerce. Containers often are shipped to the site of use before being opened. 



The global movement of goods and biota today have increased the problem, but 

 introduction of exotic biota lias been practiced from the time of ancient European, 

 Egyptian, and Asian trade, through the spread of European culture around the 

 world since the 15th century. The European colonists often moved promising plant 

 cultivars and livestock animals to their new worlds to "imorove" their agricuitiire 

 and shipped new world biota of potential value back to the homelands for potential 

 economic gain, as evidence of the bounty of the new world. 



Many products that have been transported to our country are important to us 

 today. Products such as apples, cherries, peaches, peanuts, wheat, horses, cattle, 

 swine, and sheep, are examples of introductions that have become naturalized and 

 a part of our culture. On the other hand, many imports have been tragic. Some of 

 the tragic imports indude many human diseases, small pox, tuberculosis, etc.; many 

 agricultural pests, including Chestnut blight, leafy spurge, kudzu, Russian thistle, 

 gypsy moth, fruit flies, africanized honey bee, boll weevil; and nuisances of the 

 household and stored products, some cockroaches, et cetera. 



Competitive advantage of successful invading exotic species 



Some species are particularly suited to invading new habitats. Scientists cat- 

 egorized these species several decades ago and called them "weedy species". Most 

 migrant plants have characteristics of weedy species. They have very high reproduc- 

 tive rates. They produce many seeds, most of which do not survive unless they find 

 their way to locations of minimal competition. Weedy species often have seeds that 

 are designed to be carried long distances from their home site either by the wind, 

 water, on the hair or fiir coats of animals or even in the digestive tracts of birds 

 and other animals. Weedy species are good competitors, having extensive root sys- 

 tems that are very effective at extracting water and nutrients from the soil, they 

 can spread expansively to shade other plants and to get their sunlight, they can give 

 off toxic chemicals which repel or inhibit the growth of other plants, and they toler- 

 ate or are immune to attack of native microorganisms, insects, or vertebrate 

 herbivores that have not yet adapted to their defenses. 



