STUDY GUIDE FOR PEST CONTROL ADVISERS: NEMATODES

II. NEMATODE DISTRIBUTION PATTERNS

A. Geographic Patterns

1. Describe how and why distribution patterns of different nematodes species vary. (REVIEW)
2. Describe how nematode population levels fluctuate in an annual crop from harvest of one crop in fall to planting of another in spring and harvest of that crop in the next fall. (REVIEW)
3. Describe how nematode populations fluctuate throughout the year on an established perennial crop. (REVIEW)
4. Identify a nematode group whose distribution is mainly limited by soil texture in California. (REVIEW)
5. List three reasons why root-lesion nematodes are widely distributed in California.
6. Describe how stem and bulb and foliar nematodes are distributed to new areas of the state. (REVIEW)
7. Identify the major distribution determinant of:
• a. citrus nematodes; (REVIEW)
• b. cyst nematodes. (REVIEW)
8. Describe the impact of host preference on the distribution of the common root-knot nematode species. (REVIEW)

1. Understand that different nematodes are adapted to different soil types. Give an example of a nematode that is more problematic in sandy soils. (REVIEW)
2. List two ways that irrigation practices can influence nematode patterns. (REVIEW)
3. Describe how the following factors can influence distribution of some nematode species within the field:
• a. initial introduction site; (REVIEW)
• b. soil type patterns; (REVIEW)
• c. placement of infested plant material; (REVIEW)
• d. cropping patterns; (REVIEW)
• e. movement of agricultural equipment. (REVIEW)

1. Know the distance most plant-parasitic nematode species can move through the soil in one year. (REVIEW)
2. Describe how nematodes move from field to field. (REVIEW)
3. Describe the role of irrigation on inter-field distribution of nematodes. (REVIEW)
4. Describe the value of quarantine in limiting the distribution of nematode species. (REVIEW)

1. Identify the primary factor that determines the vertical and horizontal distribution of nematodes in the soil. (REVIEW)
2. Identify the site of greatest nematode population levels in:
• a. established orchards and vineyards; (REVIEW)
• b. annual field and vegetable row crops. (REVIEW)

1. List the nematode groups most likely associated with the following crops: (REVIEW)
• a. deciduous fruit trees; [www.ipm.ucdavis.edu - Agricultural Pest Management Guidelines]
• b. deciduous nut trees; [www.ipm.ucdavis.edu - Agricultural Pest Management Guidelines]
• c. citrus; [www.ipm.ucdavis.edu - Citrus Pest Management Guidelines]
• d. grapes; [www.ipm.ucdavis.edu - Grape Pest Management Guidelines]
• e. vegetables; [www.ipm.ucdavis.edu - Agricultural Pest Management Guidelines]
• f. tomato; [www.ipm.ucdavis.edu - Tomato Pest Management Guidelines]
• g. alfalfa; [www.ipm.ucdavis.edu - Alfalfa Pest Management Guidelines]
• h. cotton; [www.ipm.ucdavis.edu - Cotton Pest Management Guidelines]
• i. sugarbeets; [www.ipm.ucdavis.edu - Sugarbeet Pest Management Guidelines]
• j. turfgrass. [www.ipm.ucdavis.edu - Turfgrass Pest Management Guidelines]
2. List the resources available to help PCAs determine what nematodes affect a given crop. (REVIEW)

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