CIS 538 rev. Part 5

Fall Management
Beyond a certain date, (usually in late August or September). bloom set will not result in additional mature seed yield. Should you leave bees in the field after this time?
  1. Remove nest materials after bloom set .
  2. Remove nest materials after October 15.
  3. Evaluate and grade bee nests.
  4. Further Information.

I. Remove nest materials soon after the last day that bloom set will result in mature seed production.

Advantages:

  1. Maximum bee-nesting activity has ended.
  2. All bee larvae will have ample time to develop to the overwintering, prepupal stage.
  3. Care can be taken to gather, grade and store filled nesting materials.
  4. Removing shelters from seed fields aids harvesting operations.
  5. Most bee cells created this late in the season are likely to be males anyway.
  6. The sooner bees go into cold storage, the more likely they are to have sufficient energy reserves available to emerge successfully in the spring (see report on mortality during incubation).
  7. Early nest removal decreases the number of second generation bees. Second generation bees normally suffer higher chalkbrood disease levels and expose non-diseased first generation bees to chalkbrood spores which they will carry into next year's nesting material.
  8. Reduces chances of filled nesting materials being stolen.

Disadvantages:

  1. The move may disturb and kill some developing larvae.
  2. A smaller "gross increase of bees" is likely (but the bees will be freer of disease and more likely to emerge, see #6 & 7 above under "advantages").
  3. At this time of year other activities may take precedence.
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II. Remove nest materials to winter storage after October 15 or after a killing frost.

Advantages:

  1. Removing shelters from seed fields aids harvesting operations.
  2. Compared with not removing nests, reduced chance of bees and nesting materials being stolen.
  3. Care can be taken to gather, grade and store filled nesting materials.

Disadvantages:

  1. The move may disturb and kill some developing larvae (but mostly males at this time).
  2. Nests have a longer exposure to the elements, predators and parasites.
  3. If temperatures have been warm, bees may use energy reserves, and are less likely to emerge successfully in the spring (see report on mortality during incubation).
  4. The higher the percentage of second generation bees allowed to renest, the higher may be the overall chalkbrood level.
  5. The risk of theft is greater for nesting material left in the field.
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III. Evaluate and grade bee nests as they are gathered for winter storage. (An x-ray analysis may help with this process).

Advantages:

1. Nesting materials can be easily evaluated and segregated for storage and phasing out the next year.

2. Evaluating bee and pest populations during the "off" season can help in making decisions about buying and selling bees and the need to phase out nesting material.

Disadvantages:

1. The time requirement for evaluating bees may be too high during the harvest season.

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Further Information:

Fall and winter management 
Sampling bee cells
Wayne Mennie's sampling advice
Cocoon testing lab results
Comparison of lab results
Mortality during incubation

Stephen, W.P. 1995. How and where were they raised? – Critical management considerations in Megachile. 26th Northwest Alfalfa Seed Growers Winter Seed School. 27-35.
If you have comments, corrections, or additions to the information provided in this document, contact Karen.
CIS 538 Contents:
INTRODUCTION
WINTER 
SPRING 
SUMMER 
FALL
OTHER 
Phase out
Shelter Size and Design
Nesting Material
Buying bees and/or loose cells
Sanitation
Avoiding theft; Purchase precautions.
ABOUT THE AUTHORS
Pollination Ecology

Revised Nov. 18, 2000.