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Am I eating genetically engineered squash or zucchini?
History and prevalence of GE squash and zucchini.

It is possible, but very unlikely. Seeds for several GE varieties of both yellow crooked-neck squash and green zucchini are marketed by Asgrow Vegetable Seeds, but very few farmers have adopted them. Although the varieties are engineered to be resistant to two or three important squash viruses, they are still susceptible to others- making many farmers feel that they are not worth the higher-priced seeds.

Squash and zuchini are the same species-- GE traits were first engineered into yellow squash, and then transferred to zucchini by conventional breeding.
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The first variety of genetically engineered yellow squash was approved for marketing at the end of 1994, earning it the distinction of being the second GE crop cleared by US regulators (Calgene's "FlavrSavr" tomato was first). Developed by the Asgrow Seeds division of Upjohn Pharmaceuticals, the new variety was resistant to two viruses which plague many squashes and melons-- Watermelon Mosaic Virus 2 (WMV2) and Zucchini Yellow Mosaic Virus (ZYMV). Farmers planted the GE yellow squash in the 1995 growing season and it first reached markets in the spring of 1995. Unlike the FlavrSavr tomato (which had been available in a few markets since the previous fall), the precedent-setting GE squash was not labeled when it reached consumers.

At the same time, the Asgrow Seed Company was caught up in the ag-biotech merger frenzy of the mid-90's. First, Upjohn sold Asgrow to the Mexican multi-national Empresas La Moderna (ELM), which was rapidly expanding its investment in ag-biotech (ELM also purchased controlling interests in Petoseeds and DNA Plant Technologies around the same time). By the end of the squash's first commercial growing season, ELM had fused Asgrow Seeds with Petoseeds to become the Seminis Seed Co. in late 1995.

[To make things even more confusing: ELM sold Asgrow's soybean division to Monsanto in 1997-and both retain the Asgrow name. Monsanto's Asgrow Seed Co. sells soybeans and field crop seed, while ELM's Asgrow Vegetable Seed Co. is limited to vegetables (including the GE squashes).]

Despite the corporate maneuvering, Asgrow Vegetable Seeds continued to work with GE squashes. By 1996, Asgrow had transferred the GE virus-resistance from yellow squash to zucchini by conventional breeding (yellow squash and zucchini are the same species and readily interbreed).

The WMV2-ZYMV resistant yellow squashes and zucchini were not widely adopted by farmers. When squashes are infected with WMV2 and ZYMV, they are also usually infected with a third common virus at the same time: Cucumber Mosaic Virus (CMV). Resistance to only two of the three viruses was not that useful to growers, who still had to contend with CMV. By 1997 however, Asgrow had genetically engineered its squash variety to be resistant to all three viruses, and this variety was first planted by growers in 1998.

The adoption of Asgrow's GE varieties has still been very limited due to the multiple-virus problem: when squashes are infected by viral disease, they are often infected by several different viruses at the same time. A viral disease is often slowed by spraying a field with insecticides to kill aphids (which spread the viruses from plant to plant), or spraying herbicides to reduce the places the aphids can live. If a GE variety is resistant to some viruses but not others, the farmer still has to use the normal control measures, and sees little cost savings to offset the higher-priced GE seeds.

Asgrow sells six varieties of GE yellow squash and zucchini: Prelude II and Patriot II (yellow squash, 2-virus resistance), Destiny III and Liberator III (yellow squash, 3-virus resist.), Independence II and Declaration II (zucchini, 2-virus resist.).
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