Unit 6: Nematode Management - Practice Quiz

1 Which cultural practice helps manage nematodes by interrupting their life cycle?

2 What is a non-host crop?

3 Why are infected crop residues removed from a field?

4 Which practice reduces nematode hosts growing between crop seasons?

5 What is soil solarization?

6 Which physical agent is commonly used to disinfest nursery soil?

7 Hot-water treatment is commonly used to remove nematodes from which material?

8 Biological management of plant-parasitic nematodes mainly uses what?

9 Which organism is a well-known nematode-trapping fungus?

10 Which bacterium is commonly known as a parasite of plant-parasitic nematodes?

11 What is one major purpose of adding organic amendments to nematode-infested soil?

12 What is a chemical used specifically to control nematodes called?

13 Which type of nematicide forms a gas or vapor that moves through soil?

14 Why must the label directions of a nematicide be followed?

15 What is the main purpose of plant quarantine?

16 Which item is most likely to spread nematodes to a new area?

17 A phytosanitary certificate generally indicates that a plant shipment has been what?

18 What is a nematode-resistant plant variety?

19 What does plant immunity to a nematode mean?

20 Which plant type usually allows a nematode to reproduce readily?

21 A farmer observes severe root-knot nematode damage in a tomato field every year. Which cultural practice would most directly reduce the nematode population before planting tomato again?

22 Which situation would make the use of a nematode-resistant crop variety especially useful as part of a cultural management program?

23 A grower removes weeds from a nematode-infested field even when no crop is present. What is the main management benefit of this practice?

24 Soil solarization is most effective when the soil is moist, finely prepared, and covered with transparent plastic during a period of strong sunlight. Why does soil moisture improve the treatment?

25 A nursery frequently spreads nematodes through contaminated potting soil. Which physical method would best reduce this risk before seedlings are transplanted?

26 Why should farm tools be cleaned before being moved from an infested field to a nematode-free field?

27 A biocontrol product contains a fungus that traps or infects nematodes in soil. Which condition would most likely support its effectiveness?

28 Which practice would best support the activity of naturally occurring nematode-antagonistic microorganisms?

29 A farmer applies a microbial nematicide but obtains poor control because it is used together with a chemical that kills many soil microorganisms. What is the most likely explanation?

30 A farmer needs to apply a chemical nematicide to a localized planting bed. Which approach is generally most appropriate for reducing unnecessary chemical exposure?

31 Why is it important to follow the label-recommended waiting period after applying a nematicide to soil?

32 A nematicide gives excellent control during the first season but poor control after repeated use. Which management principle is most relevant to this observation?

33 A nursery imports planting material from a region known to contain a serious nematode pest. Which quarantine measure would provide the strongest initial protection?

34 Why are soil-free or certified-clean roots preferred when transporting vegetative planting material between regions?

35 A quarantine station detects a nematode infestation in a shipment of planting material. What is the most appropriate immediate action?

36 A resistant crop variety allows nematode juveniles to enter roots but prevents them from completing development. What type of resistance is illustrated?

37 A plant detects nematode-derived molecules and responds by strengthening nearby cell walls and producing defense compounds. This response is best described as:

38 A farmer plants the same nematode-resistant cultivar for many consecutive seasons, and control gradually declines. Which explanation is most plausible?

39 Which management strategy would best preserve the usefulness of a nematode-resistant variety over several growing seasons?

40 A susceptible plant develops localized cell death around nematode feeding sites, restricting further development of the pathogen. This reaction is most closely associated with:

41 A three-year crop rotation suppresses Meloidogyne incognita less than predicted, although each cash crop is classified as a poor host. Field surveys reveal dense populations of a weed that is an excellent host. Which interpretation best explains the failure?

42 A grower uses a susceptible trap crop to reduce a sedentary endoparasitic nematode. At which point should the trap crop normally be destroyed for maximum suppression?

43 Two organic amendments contain equal total nitrogen. Amendment X has a low carbon-to-nitrogen ratio and decomposes rapidly, whereas amendment Y has a high ratio and decomposes slowly. Under otherwise identical conditions, why might X provide stronger short-term nematode suppression?

44 Bare fallow with repeated tillage lowers a root-knot nematode population during a dry season but causes severe erosion and loss of soil organic matter. Which replacement most directly preserves the nematode-management mechanism while reducing those costs?

45 Two adjacent plots are solarized for the same period with identical transparent polyethylene. Plot A is irrigated near field capacity before covering; Plot B is dry. Plot A generally achieves greater suppression at depth because moist soil:

46 A hot-water treatment kills nematodes inside dormant planting material, but a small increase in exposure time also damages the plant. What is the most defensible basis for selecting the treatment schedule?

47 After steam treatment of greenhouse substrate, nematodes survive mainly in compacted clods near the edge of the treatment bed. Which monitoring change would best reveal this treatment failure?

48 Why can Pasteuria penetrans provide weak control immediately after introduction but stronger suppression after repeated susceptible crops, provided compatible nematode hosts are present?

49 A fungus that primarily parasitizes eggs is applied only after most root-knot nematode eggs have already hatched. Which change is most likely to improve control in the next crop?

50 A small amount of soil from a nematode-suppressive field transfers suppression to untreated soil. The effect disappears when the donor soil is sterilized before transfer. Which conclusion is best supported?

51 A volatile soil fumigant is injected into a field containing large dry clods, then the surface is left unsealed. Why is control likely to be spatially inconsistent?

52 A nonfumigant nematicide has low mobility and mainly affects juveniles near treated roots. Which placement strategy is most likely to maximize efficacy while limiting unnecessary environmental loading?

53 Following nematicide application, soil counts fall sharply for two weeks, but root galling and the final egg population are similar to those in untreated plots. Which inference is most justified?

54 A quarantine inspector samples independent units from a shipment. If each sampled unit has a probability of of containing a detectable nematode, what minimum sample size gives at least a probability of detecting the pest at least once?

55 Imported dormant plants test negative at entry, but the target nematode may occur at low density inside roots and becomes detectable only after active growth. Which quarantine measure best addresses this limitation?

56 A molecular assay detects target nematode DNA in heat-treated planting material, but no intact nematodes are recovered. What additional evidence is most important before concluding that the consignment presents an establishment risk?

57 Cultivar R supports significantly fewer nematode eggs than a susceptible control, whereas cultivar T supports similar egg numbers but suffers much less yield loss. How should R and T be classified?

58 A tomato cultivar carrying the Mi-1 resistance gene controls an avirulent root-knot population at moderate soil temperature but permits substantial reproduction during prolonged high temperatures. What is the best management interpretation?

59 Which breeding and deployment strategy is most likely to increase the durability of resistance against a genetically variable nematode population?

60 No nematodes reproduce on a candidate plant in three inoculation tests. Which experimental design is necessary before claiming immunity rather than an ineffective inoculum or escape from infection?