31. Mechanical weed control would be most effective on:
A. Submerged weeds
B. Emerged weeds
C. Plankton
D. Algae
32. The minimum water depth of 2 feet will prevent rapid establishment of aquatic vegetation.
A. True
B. False
33. Starting a fertilizer program early in the summer will assist in controlling weeds.
A. True
B. False
34. Controlling weeds by preventing light penetration is the principal behind applying:
A. Lime
B. Inert Dyes
C. Fertilizer
D. B&C
35. Which of the following statements is not true concerning the white amur?
A. They prefer submerged weeds
B. They must be triploid in Ohio
C. They live up to 15 years
D. They prefer algae
36. Which of the following is not true concerning the white amur?
A. White amurs have a natural tendency to move with moving water
B. They should be at least 8 inches in length when stocked where fish
already exist in a pond
C. They are the ultimate aquatic weed control tool
D. Copper sulfate can kill white amurs
37. Inert dyes:
A. Helps to control both filamentous algae and submerged weeds
B. Are usually blue in color
C. Are not effective in water less than 2 feet deep
D. All of the above
31. Correct Answer: B, OPM
Explanation: Mechanical weed control can be effective against emergent weeds such as cattails and some submerged weeds and should be started early and repeated to eliminate the food supply in the underground tuber causing it to die.
32. Correct Answer: B, OPM
Explanation: Eliminating shallow areas will help control weed growth. A minimum water depth of 3 feet will prevent rapid establishment of aquatic vegetation.
33. Correct Answer: A, OPM
Explanation: Maintenance of a level of fertility high enough to foster plankton population will cloud the water and prevent light penetration necessary for submerged weed growth.
34. Correct Answer: D, OPM
Explanation: Fertilizers to encourage a plankton bloom and inert dyes both can reduce light penetration which helps to control both filamentous algaes and submerged weeds.
35. Correct Answer: D, OPM
Explanation: Filamentous algae is the least desirable food of amurs. Other aquatic plants will likely be eaten first.
36. Correct Answer: C, OPM
Explanation: The white amur should be considered as another "tool" for aquatic weed control and not the ultimate solution. Amurs represent a biological control option that may reduce the need to use aquatic herbicides.
37. Correct Answer: D, OPM
Explanation: Inert dyes reduce light penetration and thereby controls filamentous algaes and submerged weeds. They are usually blue in color and are not effective in water less than 2 feet deep.