1 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. 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. 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. European Corn Borer (ECB) • ECB (Ostrinia nubilalis) 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. ECB Damage European corn borer caterpillars damage: 1. The ears of corn. 2. The stalks, chewing tunnels causing the plants to fall over. Development of Insect-Resistant Plants • Genetic material is introduced from different species and often different kingdoms of organisms. • Bacillus thuringiensis (Bt), a soilborne 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 warmblooded animals, such as birds. 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. Problems With Pesticides 1. 2. 3. 4. 5. 6. 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. 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. 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. Bt & Monarch Caterpillars Scientific research backs data: 1. Monarch caterpillars are not very sensitive to pollen from most types of Bt corn - the exposure is too low to be significant. 2. Other data shows no ill effects for black swallowtail butterfly. 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. 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%. 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 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.