Evolution of antibiotic and pesticide resistance in bacterial and pest populations

Oriental Fruit Fly Pesticide Resistance

Overuse of pesticides to control pest populations in fruit and vegetable commodities has led to the development of pesticide resistance among Bactrocera dorsalis, more commonly known as the oriental fruit fly. Pesticide resistance occurs when resistant individuals reproduce and the resistance to their offspring. If the pesticide is repeatedly used against a given population, the resistance will strengthen and a greater population will survive. It has been estimated that more than 500 species of insects, mites, and spiders have developed some level of pesticide resistance, a phenomenon that was predicted by Rachel Carson in her book Silent Spring (Gut, 2007). Despite developing resistance to pesticides meant to control oriental fruit fly populations, eradication has been achieved through the use of quarantine and fumigation programs.

Various insecticides have been used to combat oriental fruit flies including fenthion, fenitrothion, formothion, malathion, naled, trichlorfon, methomyl, fenvalerate, and cyfuthrin. It has been determined that resistance to organophosphates and methomyl has occurred and biomechanical mechanisms have been recorded in Diptera, Hemiptera, Homoptera, Coleoptera, Lepidoptera, and Hymenoptera (Hsu et al., 2004). Pesticide resistance occurs when resistant individuals reproduce and the resistance to their offspring. It has been determined that "physiological mechanisms of insecticide resistance in insects include decreased rates of cuticular penetration, increased detoxification of the toxicants, decreased target site sensitivity, and increased sequestration (Hsu et al., 2004).

Infestation of the oriental fruit fly has been recorded in more than 150 fruits and vegetables with avocado, mango, and papaya being the most commonly attacked. Injury to the fruit occurs through oviposition punctures and subsequent larval development (Weems et al., 2010). Infestations have been devastating to the agriculture industry; in Hawaii, the oriental fruit fly has infested more than 125 hosts; and infestations of 50%-80% have been recorded in pear, peach, apricot, fig, and other fruits in West Pakistan. The oriental fruit fly is considered the principle mango pest in the Philippines and was a serious pest of citrus and subtropical fruits in Japan until its eradication in 1985 following an intense 18-year eradication program. Eradication was achieved in Japan in 1985 through the implementation and use of insecticide-impregnated fiber-blocks or cotton containing methyl eugenol, a powerful male attractant, and sterile insect technique (Weems et al., 2010). Additionally, Steiner traps are baited with lure and toxicant and used to monitor oriental fruit fly presence (Weems et al., 2010).

The introduction of the oriental fruit fly, as well as other fruit flies, into the United States has created large economic losses from the destruction and spoilage of the host fruit by the larvae, the costs associated with the implementation of control measures, and "loss of market share due to restrictions on shipments of host commodities" ("Exotic Fruit Fly Risks," 2006). With the market value of exotic fruit fly host commodities totaling more than $7.2 billion in 2002, the damage incurred by an uncontrolled fruit fly infestation could prove to be astronomical ("Exotic Fruit Fly Risks," 2006).