exam4

(8)1. Distinguish between natural control and biological control of insects.

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(12)2. Indicate how the following cultural practices are effective in control of weeds.

Rotation of crops _____________________________________________________

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Application of mulches ________________________________________________

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Burning of fields _____________________________________________________

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()3. Why are perennial weeds considered more difficult to control than annual weeds?

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(12)4. Indicate the value of the following methods of tillage on control of weeds.

Preparation of seedbed ________________________________________________

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Intertillage of crops _________________________________________________

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Fallow tillage ________________________________________________________

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(12)5. List three practices in soil management that may be used to control diseases and indicate how these practices are effective in control of diseases.

a. Practice ___________________________________________________________

Effectiveness _________________________________________________________

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b. Practice ___________________________________________________________

Effectiveness _________________________________________________________

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c. Practice____________________________________________________________

Effectiveness__________________________________________________________

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(12)6. Evaluate the following plant-derived products for their value and effectiveness in control of insects.

Rotenone ______________________________________________________________

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Nicotine ______________________________________________________________

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Pyrethrins ____________________________________________________________

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(12)7. Indicate the effectiveness and give one example of how the following practices are effective in control of diseases of plants.

a. Maintenance of high soil fertility _________________________________

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Example _______________________________________________________________

b. Control of weeds ___________________________________________________

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Example _______________________________________________________________

c. Control of insects _________________________________________________

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Example________________________________________________________________

(12)8. Describe an example of how genetic engineering, plant breeding, or plant selection has contributed to the development of the following traits in plants.

Resistance to plant diseases __________________________________________

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Resistance to insect pests of plants __________________________________

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(4)9. List four practices that one might follow to lessen damping-off disease of seeds and seedlings.

a. ____________________________________________________________________

b. ____________________________________________________________________

c. ____________________________________________________________________

d. ____________________________________________________________________

(8)10. What are the specific target organisms of the following pest-control practices? (name the pest, e.g., tent caterpillars).

Applications of diatomaceous earth ____________________________________

Applications of lime-sulfur dusts _____________________________________

Applications of dormant oil ___________________________________________

Applications of Bacillus thuringiensis ________________________________

Applications of whitewash _____________________________________________

Use of reflective mulches _____________________________________________

Use of baits with beer _______________________________________________

Acidification of soil _________________________________________________