Chapter 2: Effects Of Pesticide Applications On The Aquatic Environment

Question 1

Herbicides are used to control what two types of plants?

Answer 1

Algae and vascular plants

Question 2

Insecticides are used to control what type of pest?

Answer 2

Insects

Question 3

Piscicides are used to control what type of pest?

Answer 3

Fish

Question 4

True or false: pesticides applied according to the label pose a large threat to the environment

Answer 4

False: when pesticides are applied according to the label instructions and follow safety precautions stated, they pose little threat

Question 5

What adverse effects can a misapplication of a pesticide cause non target organisms?

Answer 5

Acute toxicity, modifying habitats, and altering oxygen levels or food quality/quantity

Question 6

True or false: one species may be more susceptible to a particular chemical then another

Answer 6

True: for example trout are more susceptible to copper sulfate than other species

Question 7

True or false: the reaction of a species to chemical could depend on the sex, size, age of the exposed individual

Answer 7

True

Question 8

True or false: chemical or physical differences in the water may affect an animals response or pesticidal action

Answer 8

True: for example, copper sulfate decreases in pesticidal activity with increased water hardness

Question 9

Insecticides and piscicides are generally nontoxic to plants unless a ____ is added that is phytotoxic

Answer 9

Adjuvant

Question 10

____ applied to or near what have the potential of moving off target with water movement

Answer 10

Herbicides

Question 11

Use herbicides carefully if ____ plants grow nearby.

Answer 11

Desirable

Question 12

Precautionary statements to warn of potential fish toxicity are shown where?

Answer 12

On both insecticide and herbicides labels

Question 13

What three things play a role in the ultimate reaction of fish to a toxin?

Answer 13

Species, nature of water, and kind of chemical

Question 14

True or false: piscicides are almost always lethal to fish

Answer 14

True: they have little selectivity

Question 15

True or false: active ingredients of most herbicides and piscicides (except a role in and xylene) are not harmful to invertebrates

Answer 15

True, when used at recommended dosages

Question 16

What when applied to water can reduce the population of non target aquatic invertebrates (crabs, shrimp, insects)?

Answer 16

Insecticides

Question 17

Use caution when applying ____ because they can be highly toxic to bees and other beneficial insects.

Answer 17

Insecticides

Question 18

Precautions may be necessary to protect certain bird species from ____ applications.

Answer 18

Insecticide

Question 19

True or false: some herbicides and piscicides used in aquatic resource management may be a potential hazard to people for a period of time

Answer 19

True. Treated water may be unsafe for swimming, livestock watering, or irrigation. Fish may be unfit for consumption.

Question 20

Pesticides are often blamed for a phenomenon called swimmer itch. Is it actually caused by pesticides?

Answer 20

No. It’s caused by a parasite associated with snails and water birds.

Question 21

True or false: pesticides may cause subtle changes and indirectly modify an aquatic ecosystem.

Answer 21

True. Both physically and biologically.

Question 22

Any reduction in quantity and quality of ___ affects the chemical and physical environment and thus the animal community structure.

Answer 22

Aquatic plants

Question 23

____ contribute to and affect the chemical and physical nature of aquatic ecosystem.

Answer 23

Plants

Question 24

Removal of aquatic plants or algae lower the basic productivity (_____ and ____) of an aquatic ecosystem.

Answer 24

Food and oxygen.

Question 25

You can avoid causing ____ in the water by treating only part of a weed infested area at a time. This gives fish an opportunity to move to untreated water where matter is not decomposing.

Answer 25

Low oxygen

Question 26

Plants and algae produce ____ while fish and invertebrates consume ___.

Answer 26

Oxygen

Question 27

Temporary reductions in ____ population replenish with time by migration into previously treated areas or gradual repopulation by survivors.

Answer 27

Invertebrates

Question 28

Due to concerns for ____ depletion resulting from decaying matter, herbicide labels may recommend partial treatment in steps.

Answer 28

Oxygen

Question 29

True or false: herbicide concentrations in fish are higher than its surrounding environment.

Answer 29

False. The concentration of herbicides in fish will NOT be higher than its environment. Fish rapidly excrete herbicides. The levels in fish will decline as soon as they leave the treated environment.