<p style="text-align: justify;"><b>Outcrossing</b></p>

<p style="text-align: justify;">Since pollen production and viability were unchanged by the genetic modification resulting in TC1507, pollen dispersal by wind and outcropping frequency should be no different than for other maize varieties. Gene exchange between TC1507 maize and other cultivated maize varieties will be similar to that which occurs naturally between cultivated maize varieties at the present time. In Canada and the United States, where there are no plant species closely-related to maize in the wild, the risk of gene flow to other species appears remote. Feral species related to corn, as found within Canada or the United States, cannot be pollinated due to differences in chromosome number, phenology (periodicity or timing of events within an organism&rsquo;s life cycle as related to climate, <i>e.g.</i>, flowering time) and habitat.<br />
Maize (<i>Zea mays</i> ssp. mays) freely hybridizes with annual teosinte (<i>Zea mays</i> ssp. mexicana) when in close proximity. These wild maize relatives are native to Central America and are not present in Canada and the United States, except for special plantings. Tripsacum, another genus related to Zea, contains sixteen species, of which twelve are native to Mexico and Guatemala. Three species of Tripsacum have been reported in the continental United States: <i>T. dactyloides, T. floridanum</i> and <i>T. lanceolatum</i>. Of these, <i>T. dactyloides</i>, Eastern Gama Grass, is the only species of widespread occurrence and of any agricultural importance. It is commonly grown as a forage grass and has been the subject of some agronomic improvement (<i>i.e.</i>, selection and classical breeding). <i>T. floridanum</i> is known from southern Florida and <i>T. lanceolatum</i> is present in the Mule Mountains of Arizona and possibly southern New Mexico. Even though some Tripsacum species occur in areas where maize is cultivated, gene introgression from maize under natural conditions is highly unlikely, if not impossible. Hybrids of Tripsacum species with <i>Zea mays</i> are difficult to obtain outside of the controlled conditions of laboratory and greenhouse. Seed obtained from such crosses are often sterile or progeny have greatly reduced fertility.</p>

<p style="text-align: justify;"><b>Weediness Potential</b></p>

<p style="text-align: justify;">No competitive advantage was conferred to TC1507 that would render maize weedy or invasive of natural habitats, since none of the reproductive or growth characteristics were modified. Cultivated maize is unlikely to establish in non-cropped habitats and there have been no reports of maize surviving as a weed. <i>Zea mays</i> is not invasive and is a weak competitor with very limited seed dispersal.</p>

<p style="text-align: justify;"><b>Secondary and Non-Target Adverse Effects</b></p>

<p style="text-align: justify;">The history of use and literature suggest that <i>Bt</i> proteins are not toxic to humans, other vertebrates, and beneficial insects.</p>

<p style="text-align: justify;">Maize inbreds and hybrids expressing the Cry1F protein were compared to their non-transformed counterpart for relative abundance of beneficial arthropods, including: lady beetles (<i>Cycloneda munda</i> &amp; <i>Coleomegilla maculata</i>), predacious Carabids, brown lacewings (Hemerobiidae), green lacewings (<i>Chrysoperla plorabunda</i>), minute pirate bugs (<i>Orius insidiosus</i>), assassin bugs (Reduviidae), damsel bugs (Nabidae), Ichneumonid and Braconids (parasitic wasps), damselflies and dragonflies, and spiders. Visual counts showed no significant differences between the number of arthropods collected in TC1507 maize and the non-transgenic isolines with two exceptions. There was a significantly greater number of lady beetles in the 1507 line (1.2 per test plant vs. 0.6 per control plant), and significantly more Orius were found in the 1507 line then the non-transgenic line on two of the three sample dates. In summary, these field studies demonstrated that Cry1F had neither a direct nor an indirect effect on the beneficial arthropod populations.</p>

<p style="text-align: justify;">Specific feeding trials were also carried out with a number of non-target species, including honeybee larvae and adults, green lacewing, parasitic hymenopterans, ladybird beetles, daphnia (aquatic invertebrates), earthworm, and collembola (soil dwelling invertebrates). In all cases there were no observable adverse effects.<br />
An additional study was conducted on the effect of Cry1F on neonate monarch butterfly larvae when fed a 10,000 ng/mL diet dose. First instar larval weight and mortality were recorded after seven days of feeding. Although there was some growth inhibition, there was no mortality to monarchs fed the 10,000 ng/mL diet, the highest rate tested. Since pollen doses equivalent to 10,000 ng/mL diet are not likely to occur on milkweed leaves in nature, it can be concluded that Cry1F protein will not pose a risk to monarchs.</p>

<p style="text-align: justify;"><b>Impact on Biodiversity</b></p>

<p style="text-align: justify;">TC1507 has no novel phenotypic characteristics that would extend its use beyond the current geographic range of maize production. Since the risk of outcrossing with wild relatives in Canada and the United States is remote, it was determined that risk of transferring genetic traits from TC1507 maize to species in unmanaged environments was insignificant.</p>

<p style="text-align: justify;"><b>Other Considerations</b></p>

<p style="text-align: justify;">In order to prolong the effectiveness of plant-expressed <i>Bt</i> toxins, and the microbial spray formulations of these same toxins, regulatory authorities in Canada and United States have required developers to implement specific Insect Resistant Management (IRM) Programs. These programs are mandatory for all transgenic <i>Bt</i>-expressing plants, including TC1507 maize, and require that growers plant a certain percentage of their acreage to non-transgenic varieties in order to reduce the potential for selecting <i>Bt</i>-resistant insect populations. Details on the specific design and requirements of individual IRM programs are published by the relevant regulatory authority.</p>
