1. If there was no ECB infestation in a certain year, would a farmer gain or lose financially by planting Bt corn? Explain why. He might lose a little bit, but since there is no way to know if there will be an ECB infestation at planting time, he might still be better off to use Bt corn. There is almost always a residual number of corn borer and other insects left in the soil, even after treating a field, so the chances are too high that he might need to spray insecticides to keep the damage down, a much more expensive proposition.
Many farmers believe the extra cost to be worth the chance of a low infestation year. 2. What might happen if Bt corn affects non-target organisms such as beneficial insects or harmless insects? BT corn is much safer than spraying insecticide on the crop. Sprays kill all insects they contact, but BT only kills larvae that eat it. If the larvae are eating the corn it is a pest, so BT cannot kill harmless or beneficial insects. We are already seeing some problems with g-modified corn. Mind you that all the corn that we have from commercial growth has been modified by human selection for productivity and by conventional hybridization, even before the techniques of genetic engineering are applied,)We now know that the assurances provided by the corporations that sell the seeds that there would not be crossover of the spliced genetic material into adjacent plant varieties, we have found both herbicide resistant genes and pesticide genetic material in plants that didn’t have them previously, and were within the pollen shower (wind -dispersed pollen) of the commercial crops.
This increases chances of damage to populations of beneficial and harmless insects. You don’t have to have the genetic materials in the corn to kill diseases and pests in order to have the unwanted problems of damage to these insect populations; many pesticide sprays are non-selective enough that beneficial insects are killed along with corn ear worms, etc. 3. What might happen if ECB became resistant to Bt? ECB may have the potential to develop resistance to Bt. Insects are known for their ability to develop resistance to certain insecticides rapidly.
Resistance occurs particularly when insecticides are used repeatedly and at high concentrations. More than 500 species of insects and mites have developed resistance to insecticides and miticides. A recent Midwestern example in corn includes adult western corn rootworm resistance to Penncap-M in Nebraska. In addition, laboratory colonies of more than 15 different insect pests have developed resistance to Bt proteins, including Indian meal moth, tobacco budworm, beet armyworm, pink bollworm and Colorado potato beetle.
Moreover, the diamondback moth, a worldwide pest of cole crops, has developed high levels of resistance to Bt insecticide in field populations in Hawaii and Florida. Growers and seed companies will face the primary impacts of ECB resistance to Bt corn. Initially, while seed companies and entomologists develop strategies for countering ECB resistance, producers in problem areas might lose the option to use Bt corn. Organic growers who rely on Bt insecticides also could lose a valuable management option in these areas.
Resistance effects could be minor, though, if hybrids that express alternative proteins are effective and if they are introduced rapidly into problem areas. ECB, however, could develop cross resistance to two or more of the proteins. If entire groups of proteins are neutralized by resistance development, growers could permanently lose Bt corn and Bt insecticides as valuable management tools. This would be unfortunate for organic growers and other producers who rely on Bt insecticides.
In addition, the failure of a voluntary, proactive resistance management plan could create more regulatory pressure for future transgenic crop technologies. This could limit the use of a transgenic Bt approach for other high-value crops, such as sweet corn. 4. Discuss possible benefits and drawbacks of a transgenic organism such as Bt corn? BENEFITS: – After sowing the Bt corn crops, farmers don’t have to worry about infestation of the European corn borer, because the plants are now capable of protecting themselves against the pests.
This cuts down the heavy reliance on chemical insecticides, which leads to lower costs, labor, and environmental damage, since Bt toxin breaks down quickly in the environment because it’s naturally occurring. – Harvest yields are much higher than those achieved with conventional corn cultivation, and this helps to satisfy the rising demands worldwide. – The mode of action of Bt toxin is highly specific and extremely effective against the corn borer, so they have no detrimental effects on non-target insects upon ingestion, and are safe for humans and animals.
CONCERNS: – Low levels of Bt protein could potentially provide ideal conditions for nature to select for resistant individuals in the insect population. As a result, certain insects may evolve resistance to the Bt protein in transgenic plant in the same way they evolve genetic resistance to chemical insecticides, rendering the Bt technology less effective. – There are still ways for non-pest species to be harmed. eg. Monarch butterfly larvae raised in the lab are harmed if they’re fed pollen from Bt corn plants. but more recent studies actually suggest that Monarch larvae living in the natural environment don’t consume enough pollen to cause significant damage) – As Bt protein does not naturally occur in the food chain, it may have unrecognized potential to cause allergies, although analysis conducted on the Bt protein did not actually unearth any allergenic potential. But that’s still a risk that we have to address by routinely screening GM crops for allergenicity. – Transgenes in Bt corn plant could potentially be transferred (i. . via gene flow), via pollen or some other route, to any closely related weeds, so these wild relatives may in turn get protected from insect infestations too and end up competing with other crops for natural resources. 5. A farmer planted a field of Bt 123 corn and wants to estimate the yield in terms of bushels per acre. He counts 22 ears in 1/1000 of an acre. He determines that each ear has about 700 kernels on average. He also knows that a bushel contains about 90 000 kernels on average.
What is the farmer’s estimate of yield in bushels/acre? Let me see if I can break this down into smaller pieces ( 22 ears ) ( 1000 / acre ) ( 700 kernels / ear ) ( 1 bushel / 90,000 kernels ) = 170 bushels / acre 6. Describe the effects of the ECB infestations you used. Were all corn varieties equally effective at controlling the ECB? When tested of HIGH infestation, each corn variety showed slightly smaller growth amounts in each yield while the LOW infestation, each corn variety showed larger growth amounts from each yield.