OTTEA

Question 1

Why do we use insecticides and what are the costs of its use?

Answer 1

We use insecticides because of the need to feed an increasing population and to eliminate human disease. The costs of insecticide use are SIREN.
Secondary pest outbreak;
Increased regulation;
Resistance;
Environmental contamination;
Non-target effects

Question 2

How are insecticides used in IPM?

Answer 2

Insecticides are one component of an integrated strategy used only when necessary for management, not decimation, observing economic thresholds. In addition, protect beneficial and manage susceptibility.

Question 3

What are the two characteristics of an IPM-compatible insecticide?

Answer 3

Selective for pest insects and safe for the environment. Toxic to targets, relatively non-toxic to mammals, and safe for beneficials. Non-persistent in the environment, does not enter the water table and do not persist in soil.

Question 4

Discuss one example of compatible and one of incompatible insecticide for IPM.

Answer 4

Carbofuran is an example of an incompatible insecticide for IPM. This insecticide is more toxic for mammals than insects. Also, it is toxic to beneficials. In contrast, spinosad in an example of a compatible insecticide for IPM. This insecticide is toxic to insects but it has low toxicity for mammalian and a short half-life of 9-10 days in soil and less than one day in water.

Question 5

What are the main insecticides of the first generation?

Answer 5

Botanicals (Nicotine, rotenone, and pyrethrum) and Inorganics (Arsenicals, phosphates);

Question 6

What are the main insecticides of the second generation?

Answer 6

Organics (carbamates, cyclodienes, DDT).

Question 7

What are the main insecticides of the third generation?

Answer 7

“Biorational” approach but few targets. 
Chitin synthesis: diflubenzuron (1970)
Insect development: 
-	JH: Methoprene/hydroprene (1975)
-	Ecdysone: Tebufenozide (1992)

Question 8

How does the discover process usually work?

Answer 8

Often, starts with a natural lead. Synthesize a series and screen. Number of screens per hit has increased over the years.

Question 9

Critique the “biorational” approach of insecticides.

Answer 9

Compounds have variation but on a theme. Mode of action unknown and resistance not considered.

Question 10

What is the reality about the “renaissance” period of insecticides (1990)?

Answer 10

Industry continued to produce insecticides that are nerve poisons. This insecticides are more selective but not biorational.

Question 11

Cite three resistance mechanisms.

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Answer 11

Reduced penetration; Reduced target sensitivity; and enhanced metabolism (decreased activation and increased detoxication).

Question 12

What is the difference between multiple and cross resistance?

Answer 12

Multiple resistance is the selection of populations that express more than one mechanism of resistance. Cross resistance is the selection for resistance mechanism that confers resistance to more than one insect class.

Question 13

How are insecticides used for resistance management?

Answer 13

In a way that selection of resistant individuals is minimized.

Question 14

How can you maintain susceptible phenotypes in an IRM program?

Answer 14

Avoiding spraying insecticides; using refuge population; and rotating chemical classes of insecticides.

Question 15

What are the take home messages from Dr. Ottea’s lectures?

Answer 15

• Effects of resistance are cumulative;
• Metabolic resistance limits use of new compounds;
• Susceptibility management is an important challenge to work on.