Mass produced pollinator houses can be harmful
Note: It is always good to read research and observations that others have compiled, and this is an interesting article from Pennsylvania. The flow chart for deciding whether to buy a particular type of mason bee house is very good. We would also add: no plastic straws as they are not breathable and likely will cause mold issues. While drilled holes have been recommended in the past, we do not recommend that option. Our reasoning is that (like bamboo) they cannot be easily cleaned, so build up of mites or the fungus chalkbrood is much more likely to cause death within 1-3 years. Having removable tubes in the holes is better than not having them, but it is still hard to sanitize that type of site.
Many of us in the Willamette Valley observed an apparent die-off of blue orchard mason bees this spring when the weather got into the mid to upper 90s much earlier than usual. Although, there were reports in some areas in the Valley where it appears the heat did not affect the bees. We will learn more about the effects of the extreme heat when we harvest our cocoons in mid-October through early November.
Yes, we are all still learning about how to best help the bees!
If you have not yet taken in your Blue Orchard Mason Bee blocks/tubes, do it as soon as possible. We are trying to protect those bee cocoons from the parasitic wasps that are starting to come out now.
Remember to put the blocks/tubes in a paper bag, fold over the top, and staple it shut. Store the paper bag in your garage or shed until cocoon harvesting time, in mid-October to mid-November.
We are in the process of setting up cocoon harvesting classes. You can register in mid September at the Linn County Master Gardeners website. It is fun to see what you have in your block. It is also interesting to see what others have in their blocks/tubes. Each year we see something new along with the common issues.
HOW WILL I KNOW THE DIFFERENCE BETWEEN MY BLOCKS?
(This applies to blocks sold by Linn County Master Gardeners.)
For those who have purchased leaf cutter bee blocks, it might be helpful for you to know how identify the leaf cutter block vs the blue orchard mason bee block. Both blocks can go in the same house (just at different times of the year.)
At this point we are in the early process of learning more about how to help the leaf cutter bees. In the fall we would enjoy hearing feedback about your experiences with the leaf cutter bees (if you are putting out a block for them). For now we do not have plans to harvest the leaf cutter bee cocoons. If you want to try a leaf cutter bee block, we do have some at the Linn Extension Office, Tangent ($30.00 – cash or check to LCMGA). We do NOT have cocoons for leaf cutter bees.
This photo should help you identify your blocks.
The blue orchard mason bee blocks have 5/16” holes. The wood used was fir or a laminated Baltic birch plywood (for Spring Blue Orchard Mason Bees).
The leaf cutter bee blocks have 1/4” holes. The wood used was fir or a laminated Baltic birch plywood. The leaf cutter bee block is shorter (not as deep), so they are not pushed all the way to the back of the house opening. Be sure to tape on the extra piece of wood that was provided onto the back to create the needed dark hole (for Summer Leaf Cutter Bees).
Plans for the Rustic Bee House
Several people have asked for plans for making a bee house. Click here for the plans for making the Rustic Bee House.
We use pine or laminated Baltic birch boards. They come in six and eight inches wide and eight foot long lengths. You will need both six and eight inch wide boards. Look for ones with the fewest knots and the straightest boards.
The boards are held together by screws. The screws we use are 1-5/8 inch self-tapping T-20 star drive screws. You will cut four eight inch boards and six six inch boards. The eight inch boards are used for the sides and six inch boards are for the top, bottom and back. This would make four to five houses.
These posts are from Master Gardeners, as well as speakers we have had at various events concerning pollinators.