Controlling Insects!

1. Controlling Insects!

2. Insecticides • Identify common insect pests and select an effective control method for each. • Describe the six ways in which insects are killed by insecticides. • List the names and characteristics of the three major groups of insecticides. • Compare the six ways in which insecticides are applied. • Explain the relationship between the life cycle of insects and timing of application.

3. What is an insect? • Insectsmall animal with three defined body regions and three pairs of legs! • HEAD, THORAX, and ABDOMEN!

4. 6 Common Orders! • Orthoptera- includes the grasshopper and locust • Hemiptera - includes the true bugs such as leaf hoppers and plant bugs • Lepidoptera – moths and butterflies • Homoptera- aphids • Thysanoptera- thrips • Coleoptera- which is the largest group of the insect orders, including beetles

5. Insect grouping! • How are insects grouped? • They are grouped by the way they feed on plants. So they are grouped by their mouth parts.

6. Mouth Parts • There are six different mouth parts • Sponging • Rasping- sucking • Siphoning • Chewing-lapping • Chewing • Piercing- sucking

7. How Insecticides Kill • Chemicals must kill insects while doing little or no damage to the plant. • Stomach poisonsWork against insects that eat parts of the plant. • Sprayed or dusted on the plant • As insect eats the plant, it is poisoned through the stomach. • Insects that chew food (caterpillars, grasshoppers, beetles) are controlled by stomach poisons. • Example--Rotenone

8. How Insecticides Kill • Contact Poisonskill insects when they are hit by or come in contact with the poison. • Any type of insect can be controlled this way. • Kill by upsetting the insect’s nervous system or breathing system. • Example--malathion

9. How Insecticides Kill • Systemic poisonsenter the plant sap and move throughout the entire plant. • When insect eats parts of plants or suck plant juice, chemical is swallowed. • Effective with insects with chewing or sucking mouthparts. • Effective with insects that hide under leaves or underground. • Food crops—allow time for chemical to break down. • Example--Orthene

10. How Insecticides Kill • Fumigantscontact poisons applied in gaseous form. • Gases or fumes kill the insect after entering system through breathing pores. • Insect must absorb the poison for this insecticide to be effective. • Used to control soil-borne insects that damage roots. • ExampleTAME

11. How Insecticides Kill • Repellantsdo not kill insects, but drive them away before they attack the plant. • Examplealuminum foil (repels flying insects)

12. How Insecticides Kill • Attractants and Phermoneswork in the opposite way from repellants. • They lure insects to their death. • Page 171

13. Chemical Makeup of Insecticides • Three groups! • Inorganic Compounds • Organic Compounds • Synthetic Organic Compounds

14. Inorganic Compounds • Mineral origina mineral is used as the basis for the poison • Usually work in the form of a stomach poison. • Example—Sulfur

15. Organic Compounds • Derived from plants • Work in form of stomach or contact poisons • Example—rotenone and pyrethrum

16. Synthetic Organic Compounds • Recent origin (last 30-35 years) • Produced in the laboratory • Many are also toxic to humans. • Three Groups • Chlorinated Hydrocarbons • Organophosphates • Carbamates

17. Synthetic Organic Compounds • Chlorinated HydrocarbonsLong RESIDUAL Control (continue to kill long after application) • ExampleDDT (not used in US)

18. Synthetic Organic Compounds • OrganophosphatesContains chemicals most toxic to warm-blooded animals • Absorbed rapidly through the skin • Parathionone drop in the eye can kill a human being. • ExampleMalathion (relatively safe)

19. Synthetic Organic Compounds • Carbamatessafest insecticides on the market • Break down rapidly (2-7 days) and leave no residue to contaminate the environment • Do not build up in the bodies of warm-blooded animals • Example—Sevin