NORTH- HOLLAND The Environmental and Economic Costs of Herbicide Resistance and Host-Plant Resistance to Plant Pathogens and Insects MAURIZIO G. PAOLETTI and DAVID PIMENTEL ABSTRACT Sustainable agriculture and biodiversity maintenance would be central to a desirable development of genetic engineering. Biotic diversity on the planet is the base for all food chains, including human ones: in particular, diversity is incredibly high in tropical areas in which 30-100 million living species have been forecast. Options for genetic engineering, in order to be desirable, have to meet two needs: improve sustainability and promote biodiversity, and reduce environmental stress. Most of the current field trials that have been approved are focused on traits such as herbicide resistance, which in most cases could promote more intensive use of herbicides hazardous to the environment. Extensive research on risk assessment is either limited or nonexistent on nontarget organisms in agroecosystems in which genetically modified organisms are expected to be released. The following options are discussed in detail: (1) the B.T. endotoxine problem and the ecology of B.T. strains; (2) crops modified for herbicide resistance; (3) plants resistant to pests and diseases; (4) transfer of resistance genes from wild varieties, which are resistant, to commercial ones. Traditional breeding of promising cases (potato, apple, grape) as source ideas for sustainable agriculture and genetic engineering trends are discussed, together with some desirable and undesirable aspects of the development of genetic engineering. Introduction Proponents of genetic engineering suggest that: "With the global gene pool as raw material, and swiftly improving techniques for isolating and recombining genes, genetic engineers will soon leave behind the slow and constricted arena of selective breeding and mutagenesis" [75, p. 53]. And some enthusiasts in developing countries feel that: "the proper path for third world countries to take in developing their agriculture is to by-pass the wasteful, high-input stage and go directly from their traditional agriculture to new MAURIZIO GUIDO PAOLETTI is a soil zoologist and ecologist and has been associated with the Depart- meat of Biology at Padua University since 1983. He is currently coordinator of a European Community project to evaluate sustainability in subtropical China and is also involved in projects in the Amazon and the Andean region to monitor and promote biodiversity as a tool for sustainability. He has been visiting professor at Ohio State University, Cornell University, and Fry University of Brussels. DAVID PIMENTEL is Professor of Insect Ecology and Agricultural Sciences at Cornell University, Ithaca, NY. His research encompasses areas such as genetic engineering, biological control, energy use, sustainable agriculture, and natural resource management. Address reprint requests to Maurizio G. Paoletti, Dipartmento di Biologia, Universita degli Studi di Padova, Via Trieste 75, 35121 Padova, Italy. Technological Forecasting and Social Change 50, 9-23 (1995) © 1995 Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 0040-1625/95/$9.50 SSDI 0040-1625(94)00090-J