Ohio Pesticide Applicator Training
Field Crops
Student Workbook

Bulletin 821

1. If atrazine is the only herbicide used on continuous corn, what weed will most likely become a problem?
1. Pigweed
2. Common ragweed
3. Fall panicum
4. All of the above

Answer

2. What is the best description of fall panicum?
1. An annual grass with a wide completely green leaf blade that is covered with hair on the upper surface
2. A perennial broadleaf weed
3. An annual grass with a prominent and white midrib. The ligule is hair-like and may have hair on the sheath and under-side of the leaf blade when the plant is small.
4. A perennial grass with flat stems
5. A perennial grass with large nodes

Answer

3. Which of the following are effective cultural weed control practices?
1. Crop rotation
2. Planting at proper time to obtain adequate plant stand
3. Assure adequate drainage for optimum crop growth
4. Prevent weed seeds from getting on fields by cleaning machinery between fields
5. All of the above

Answer

4. When designing an herbicide program, which of the following should be considered?
1. Soil type
2. Tillage practices
3. Current and following crop
4. Weeds species currently and previously observed in the field
5. Cost
6. All of the above

Answer

5. Herbicide performance is not affected by:
1. Soil conditions
2. Weather conditions
3. Application evenness
4. Application rate
5. Application procedure
6. Cost

Answer

6. The difference between postemergence herbicide programs and soil applied (preplant or preemeregence) programs is:
1. The danger of a fish kill in ponds is greater for postemergence applications
2. The weather conditions before and after the postemergence application are more important than for preemergence applications
3. Thorough coverage is more important for postemergence applications compared to preemergence applications
4. All of the above
5. B & C above

Answer

7. Bicep II Magnum is the trade name for a product used in corn that contains two active ingredients. The common name for these ingredients are s-metolachlor and atrazine.
1. True
2. False

Answer

8. Atrazine needs to be applied to a corn field at 1.2 pounds of active ingredient per acre. How many gallons of AAtrex 4L should be applied to your 10 acre field?
1. 0.3 gallons
2. 1.2 gallons
3. 3 gallons
4. 4 gallons
5. None of the above

Answer

9. Soil-applied herbicide performance is affected by:
1. Soil texture
2. Organic matter content of soil
3. Soil pH
4. Soil moisture
5. Soil tillage
6. All of the above

Answer

10. Soil applied herbicides are more likely to injure crops in sandy soils which are low in organic matter.
1. True
2. False

Answer

11. High pH soils allow triazine herbicides such as atrazine and simazine to be more active, thus providing better weed control but greater crop injury.
1. True
2. False

Answer

12. Herbicides that are very toxic to plants, such as paraquat (Gramoxone), can drift to non-target crops and result in illegal residues, even if the crop is not killed.
1. True
2. False

Answer

13. Herbicides with a short period of residual soil activity and low solubility are well-suited for early preplant application.
1. True
2. False

Answer

14. Herbicides that are applied to the soil surface after the crop is planted but before the crop seedlings appear above the ground are called:
1. Early preplant
2. Preplant incorporated
3. Preemergence
4. Postemergence
5. None of the above

Answer

15. The following factors make postemergence weed control with herbicides less effective.
1. Small weeds
2. Drought conditions
3. High temperatures and relative humidity
4. Rainfall during or soon after application
5. A and C
6. B and D

Answer

16. The following factor (s) or practice (s) increase the effectiveness of postemergence herbicides without increasing the chance of crop injury.
1. Smaller weeds
2. High temperatures
3. High relative humidity
4. Use of an adjuvant such as surfactant, crop oil, or fertilizer solution with the spray solution
5. None of the above
6. B, C, and D above

Answer

17. Translocated herbicides (those that move throughout the plant) may be effective with partial foliar coverage, while contact herbicides (those that work only where they come in contact with the plant) require more complete spray coverage.
1. True
2. False

Answer

18. The following will aid in more complete foliar coverage:
1. Increased spray volume
2. Increased pressure
3. High temperature
4. High humidity
5. Addition of an adjuvant such as surfactant or crop oil concentrate
6. A and B above
7. All of the above
8. A, B, and E above

Answer

19. To reduce drift of translocating herbicides, spray droplet size needs to be increased. This can be accomplished by using air induction (AI) nozzles.
1. True
2. False

Answer

20. To maximize drift reduction and maintain excellent weed control of postemergence herbicides, which nozzle should be used?
1. Floodjet nozzle for both contact and translocating herbicides
2. Drift reducing extended range flat fan nozzle for both contact and translocating herbicides
3. Air induction (AI) nozzle for translocating herbicides and drift reducing extended range flat fan nozzles for contact herbicides at low pressure
4. Full cone nozzles for both contact and translocating herbicides

Answer

21. Drift concerns may require that an applicator make efficacy compromises for the herbicides or else choose a nozzle that is not optimum for controlling drift.
1. True
2. False

Answer

22. Reduced tillage always results in more herbicide being used for corn and soybean production.
1. True
2. False

Answer

23. Burndown herbicide (s) commonly used in no-tillage crop production is (are):
1. Roundup WeatherMax
2. Paraquat
3. Gramoxone Max
4. Glyphosate
5. All of the above
6. None of the above

Answer

24. Because herbicides are made to kill plants and not insects or animals, there is no need to handle them with as much care and respect as is necessary with insecticides or rodenticides.
1. True
2. False

Answer

25. It is against the law to apply:
1. An herbicide to a crop which is not on the label
2. More than the labeled rate of herbicide
3. Less than the labeled rate of herbicide
4. All of the above
5. A and B above

Answer

26. Which of the following spray nozzles are the most wear-resistant, but also the most expensive?
1. Brass
2. Thermoplastic
3. Hardened stainless steel
4. Copper
5. Aluminum

Answer

27. Nozzles should be replaced and the sprayer recalibrated when the output from the sprayer has increased how much from the original output when the nozzles were new?
1. 1%
2. 10%
3. 20%
4. 30%
5. 40%

Answer

28. For many of the new herbicides especially those applied postemergence, rinsing the system with water only is sufficient.
1. True
2. False

Answer

29. The order in which pesticides should be added to water or fertilizer when more than one formulation is used is:
1. Crop oil concentrates
2. Flowables or aqueous liquids (solutions)
3. Emulsifiable concentrates
4. Wettable powders or dispersable granules


1. Emulsifiable concentrates
2. Wettable powders or dispersable granules
3. Crop oil concentrates
4. Flowables or aqueous liquids (solutions)


1. Flowables aqueous liquids (solutions)
2. Crop oil concentrates
3. Wettable powders or dispersable granules
4. Emulsifiable concentrates


1. Wettable powders or dispersable granules
2. Flowables or aqueous liquids (solutions)
3. Emulsifiable concentrates
4. Crop oil concentrates

Answer

30. Drift or off-target movement of herbicides is the reason for most complaints to the Ohio Department of Agriculture concerning improper use of herbicides.
1. True
2. False

Answer

31. The extent of spray drift increases as:
1. The boom pressure increases
2. The size of spray droplets decrease
3. The boom height increases
4. The wind speed increases
5. All of the above

Answer

32. Which of the following herbicides is least volatile?
1. Clomazone (Command)
2. Dicamba (Banvel)
3. The ester formulation of 2,4-D
4. The amine formulation of 2,4-D

Answer

33. Herbicide carryover problems are increased when:
1. Soil temperatures are lower than normal
2. Rainfall is lower than normal
3. A herbicide persists for a long time
4. The application rate is higher than normal
5. The herbicide is applied later than normal
6. Next year's crop is very susceptible to damage by the herbicide
7. Next year's crop is under stress
8. All of the above

Answer

34. Herbicides for which carryover is not a problem are:
1. Atrazine (AAtrex) and Simazine (Princep)
2. Trifluralin (Treflan), chlorimuron-ethyl (Classic and Canopy XL) and imazaquin (Scepter)
3. Glyphosate (Roundup, etc.) and paraquat (Gramoxone Max)
4. All of the above
5. None of the above

Answer

35. A bioassay for herbicides is where one or more sensitive plants are grown in the "suspect" soil and compared to the growth in a similar soil not treated with the herbicide in question.
1. True
2. False

Answer

36. Traces of several common herbicides have been found in the water sources for some municipal water systems in Ohio.
1. True
2. False

Answer

37. Erosion and water run-off from newly treated crop fields are major culprits in water contamination.
1. True
2. False

Answer

38. Most instances of groundwater contamination are due to leaching of pesticides from spray loading sites, leaching from disposal sites, or back-siphoning from the sprayer into wells.
1. True
2. False

Answer

39. The potential for groundwater contamination is less:
1. On sandy soils
2. With herbicides low in water solubility
3. With higher herbicide rates
4. With persistent herbicides

Answer

40. Groundwater advisory statements are found on herbicide label (s) containing which of the following active ingredients:
1. Atrazine and simazine (AAtrex and Princep, respectively and many other products)
2. Isoxaflutole (Balance and Epic)
3. Metribuzin (and several premixes)
4. A and B
5. A and C
6. All of the above

Answer

41. Triazine herbicide injury in soybeans may result from high rates of atrazine and/or simazine (Princep) used in last year's corn crop year. Furthermore, the chance of injury is increased with the use of metribuzin containing products (such as Sencor, Canopy, Domain, Axiom, or Boundary) on the current soybean crop.
1. True
2. False

Answer

42. What is the maximum rate of atrazine that can be applied preemergence if a field is considered to be highly erodible and has less than 30% crop residue on the surface?
1. 1.6 pounds active ingredient/acre
2. 1.8 pounds active ingredient/acre
3. 2.0 pounds active ingredient/acre
4. 2.5 pounds active ingredient/acre

Answer

43. What is the total amount of atrazine that can be applied per calendar year?
1. 1.6 pounds active ingredient/acre
2. 1.8 pounds active ingredient/acre
3. 2.0 pounds active ingredient/acre
4. 2.5 pounds active ingredient/acre

Answer

44. What is the maximum amount of atrazine that can be applied in a single application for soils highly erodible with greater than 30% residue cover, soils not considered highly erodible, or for a postemergence application?
1. 1.6 pounds active ingredient/acre
2. 1.8 pounds active ingredient/acre
3. 2.0 pounds active ingredient/acre
4. 2.5 pounds active ingredient/acre

Answer

45. Herbicides that are active and applied at low rates require thorough cleaning of the sprayer and accurate calibration.
1. True
2. False

Answer

46. For which type of herbicide are adjuvants such as nonionic surfactant (NIS), methylated seed oils (MSO), crop oil concentrates (COC), and a nitrogen fertilizer (28%N or AMS) necessary to achieve maximum weed control?
1. Preemergence herbicides
2. Pre-plant incorporated herbicides
3. Postemergence herbicides
4. Residual herbicides

Answer

47. Which of the following cropping practices are most likely to cause the development of herbicide resistant weeds?
1. A corn/soybean/wheat/hay rotation, using conventional tillage, and using several different herbicide sites of action
2. Continuous soybeans, using continuous no-tillage, and using only one herbicide site of action
3. A corn/soybean/wheat rotation, using continuous no-tillage, and using several different herbicide sites of action
4. Continuous corn, using conventional tillage, and using several different herbicide sites of action

Answer

48. Which herbicide site of action has the most number of resistant weed species?
1. ACCase
2. EPSP synthase
3. Photosynthetic inhibitors
4. ALS inhibitors

Answer

49. Indicate in the first column if each weed is an annual, winter (WA) or summer (SA), biennial (B), or perennial (P) by placing an "WA, SA B, or P" in each blank. In the second column indicate if each weed is a grass (G), broadleaf (B), or sedge (S) by placing a "G, B, or S" in each blank.*

	bindweed, hedge			__________	__________
	carrot, wild			__________	__________ 
	chickweed, common 		__________	__________
	dandelion			__________	__________ 
	deadnettle, purple		__________	__________
	dogbane, hemp			__________	__________
	foxtail, giant			__________	__________ 
	foxtail, yellow			__________	__________
	johnsongrass			__________	__________	          
	lambsquarters, common		__________	__________	
	marestail/horseweed		__________	__________
	milkweed, common		__________	__________
	morning glory, tall 		__________	__________
	nutsedge, yellow		__________	__________
	panicum, fall			__________	__________
	quackgrass			__________	__________
	ragweed, common			__________	__________
	ragweed, giant			__________	__________  
	shattercane			__________	__________ 
	thistle, Canada			__________	__________ 
	velvetleaf			__________	__________
	

Answer

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture

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