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weevils, imported fire ants, European com borers, chestnut blight, nutria, etc. now 

 are accepted as part of our fauna and managed accordingly. The eradication pro- 

 gram for imported fire ant was a failure, causing more damage than good. The 

 eradication program against the Mediterranean fruit fly in California is a hotly de- 

 bated issue; and success is highly improbable. On the other hand eradication of 

 Mediterranean fruit fly in Florida was successful. A multimillion dollar eradication 

 program being pursued for citrus blackfly in Florida and Texas in the 1970's was 

 abandoned because the introduction of two microscopic, parasitic wasps from its site 

 of origin provided complete biological control in both Florida and Texas. 



Some exotic species that have become major agricultural pests have been man- 

 aged by biological control. Typically, a biological control program is conducted only 

 after it has been determined that the pest warrants control and that biological con- 

 trol is an appropriate choice of many possible approaches. Biological control is ac- 

 complished Dy first identifying the geographic source of the exotic pest, its host 

 plant(s) or animal(s), and conducting scientific searches to find and select appro- 

 priate agents from its natural enemies. These species, more exotic species, are then 

 imported according to proper protocol and safety testing to quarantine facilities 

 where specialists do more work on host relationships, host specificity, purity from 

 contamination by other species, and suitability for release. Ujpon completing these 

 quarantine protocols, application is made for release permits. Ir permits are granted, 

 tne beneficial organism(s) is released into sites highly suited for establishment and 

 spread. With appropriate care and study and with a little luck, the biological control 

 agent establishes and perpetuates itself to provide suppression of the pest exotic 

 species. Between 24 and 55% of these attempts have been successful and permanent 

 control of the exotic pests has been accomplished in over 100 cases in the U.S. and 

 over 350 cases worldwide. Of the species now invading Audubon sanctuaries, leafy 

 spurge, purple loosestrife, Brazilian peppertree, and melaleuca are being addressed 

 by biological control projects. The leafy spurge program appears to be a success with 

 the program being limited now by effective distribution or the successful biological. 

 Control agents to new sites. The purple loosestrife project is in a testing phase; ex- 

 otic biological control agents have been evaluated in the laboratory and three spe- 

 cies have been released into the environment for colonization. 



Transition from Eradication to Management 



There appears to be a point at which an exotic species is no longer threatening 

 to become establish, but is established. At such a point in this introduction, col- 

 onization, adaptation, and dispersal continuum eradication programs becorne too ex- 

 pensive and too environmentally disruptive to be practically executed. This critical 

 transition deserves special policy and budgetary attention. Once established popu- 

 lation suppression and management programs become the only alternative. 



The form of management should be ecologically based Integrated Pest Manage- 

 ment (IPM) defined as a pest and disease population management system that 

 makes maximum use of biological control agents and utilizes all suitable techniques 

 of pest suppression in a manner that is compatible with the use of these biological 

 agents and other techniques to maintain pest populations at levels below those caus- 

 ing economic injury. In the case of invading exotic organisms the IPM program 

 should involve consideration of importation of the exotic pest's natural enemies and/ 

 or antagonists for its control. A sound biological control approach for control of 

 exotics offers a successful solution for control of exotic pests, worldwide. 



Biological Control 



Biological control does not eradicate pests. It establishes a new population equi- 

 librium level, which if fully successful, maintains the pest population below levels 

 that cause concern or damage. This approach seeks to introduce in the pest's new 

 environment one or more of its long evolved natural enemies or antagonists from 

 the pest's original environment so that the pest again faces biological limits to its 

 ability to increase and spread. The fact that introduced biological control agents de- 

 pend solely upon their nost(s), the exotic pest, for survival means that the abun- 

 dance of the pest will limit the abundance of the biological control agent. Con- 

 versely, the biological control agent will limit the pest in accordance to its ability 

 to locate and propagate on the pest. This circular, negative feedback system is self- 

 limiting and self-perpetuating. 



What Is Needed 



Most programs targeted at exotic pests have involved exclusion, interdiction, re- 

 search, action, and education programs of several agencies and institutions. In the 

 past and even now, these various components have not been coordinated for the pur- 

 poses of managing exotic pest invasions in a timely and scientificallv sound manner. 

 Conflicting demands of export market constraints, international and interstate quar- 



