Controlling Insects Insecticides Identify common insect pests and

Controlling Insects!

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.

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

6 Common Orders! n n n 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

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

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

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. n n 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

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

How Insecticides Kill Systemic poisons enter the plant sap and move throughout the entire plant. n n n 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

How Insecticides Kill Fumigants contact poisons applied in gaseous form. n n 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

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

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

Chemical Makeup of Insecticides Three groups! Inorganic Compounds Organic Compounds Synthetic Organic Compounds

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

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

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

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

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)

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 warmblooded animals Example—Sevin