Bt Trait vs. European Corn Borer

1. Bt Trait vs. European Corn Borer

2. Objectives By the end of today’s lesson, you will be able to… • Explain why pest control is so important in corn/crop production. • Describe the European Corn Borer (ECB) and the damage it causes. • Describe how bacteria are used to create insect resistance in plants. • List the advantages of plants that have been genetically modified. • Identify some concerns of Bt crops.

3. Introduction • Selective breeding has been used for thousands of years to change and improve plants that are grown for food, shelter, and clothing. • This technology has made tremendous progress in the past; however, nothing has come close to improving plants as much as genetic engineering.

4. History of Insect Damage • Historically, one of the greatest problems associated with crop production has been the control of insects. • A common practice used to be to plant twice as much as needed because you could count on bugs devouring at least half the crop. • Even today with effective pesticides and management techniques, its estimated that 40% of the world’s food supply is lost to pests, disease, and spoilage.

5. European Corn Borer (ECB) • ECB (Ostrinianubilalis) is a pest of grain, particularly maize (corn). • Native to Europe. • First reported in North American in 1917. • Since its discovery, the insect has spread into Canada and westward across the United States to the Rocky Mountains.

6. ECB Damage European corn borer caterpillars damage: • The ears of corn. • The stalks, chewing tunnels causing the plants to fall over.

7. Development of Insect-Resistant Plants • Genetic material is introduced from different species and often different kingdoms of organisms. • Bacillus thuringiensis(Bt), a soil-borne bacteria discovered in 1911, is used in GM crops to disrupt the digestive process of insects, thus making the crop insect-resistant. • This bacteria is nontoxic to mammals and other warm-blooded animals, such as birds.

8. Insect-Resistant Plants (cont.) • Currently, millions of acres of Bt crops are produced all over the world and the amount is increasing. • Bt crops include: corn, soybeans, potatoes, tomatoes, apples, rice, and several vegetables. • Bt crops aren’t always widely accepted by the public.

9. Problems With Pesticides • Plants not absorbing enough pesticide to be effective. • Withdrawal periods may be required before harvest and processing. • Pesticides are very expensive and timing is important. • Sprays cannot reach all areas of the leaves/plants . • Trips though the field cost time and money. • Chemical pollution.

10. Bt Benefits • Labor costs, fuel expenses, and machinery operating costs are greatly reduced when plants have built-in resistance to insects. • Bt prevents feeding of insects on the plant, which cause damage and produce openings for fungus spores to grow. • Less insect damage equals fewer openings and less fungus damage.

11. Benefits (cont.) • In addition, Bt toxins actually kill the fungus which reduces damage in stored crops such as grain and silage. • Saves millions of dollars in pesticides costs and safer for the environment. • Reduced mycotoxins, which are potent poisons produced by fungi. • Most dramatic effects may be in third world countries.

12. Bt & Monarch Caterpillars Scientific research backs data: • Monarch caterpillars are not very sensitive to pollen from most types of Bt corn - the exposure is too low to be significant. • Other data shows no ill effects for black swallowtail butterfly.

13. How To Prevent Resistance In ECB • The EPA sets standards and requires “buffer zones” and the use of “refuges.” • Use Bt corn hybrids in fields where the risk of severe ECB infestations warrants the price premium for seed. • Carefully record and mark where Bt and non-Bt corn hybrids are planted, so Bt corn performance can be monitored and non-Bt corn can be scouted, and if needed, treated with a non-Bt insecticides.

14. Resistance Prevention (cont.) • Plant non-Bt corn refuge(s) to protect 20-30% of the ECB larval populations from exposure to Bt Cry proteins. • Plant non-Bt corn at a similar time and in close proximity to Bt corn. In corn-soybean production areas, where corn is the primary refuge, at least 20-30% of the corn acreage should be non-Bt corn. • Where spraying of non-Bt corn is anticipated, increase the refuge size to 40%.

15. Common Concerns Of The Bt Trait • Genetic pollution • Creation of a “super bug” • Possible negative impacts to wildlife • Allergen risk • Not all countries are accepting GMO’s • The fear of the unknown

16. Summary • Humans have genetically altered plants for thousands of years. • The invention of genetic engineering has greatly accelerated the process of plant improvements. • Scientists can select specific desirable genes, insert them into conventional plants, and produce super plants that have capabilities far exceeding any produced by convention means.