This year, one of my goals in the carrot seed project is to breed our own flies to avoid ordering in pupae. There are a few reasons for this:
- The current source of blue bottle fly pupae we have is from a US source. There are no local or Canadian suppliers that we can find
- Between shipping and the pupae cost, it is a significant added expense that I would like to avoid
- From a “seed sovereignty” point of view, I want to know that we can have a local means of generating a pollinator fly population so we are not dependent on an out-of-country source
Now – if this is the first time you are reading about the carrot seed project you may be a bit confused, so in short:
We are growing carrot to seed in a mesh tent so as to avoid cross pollination with Queen Anne’s lace, wild weedy relative that crosses with carrots, make the seeds unfit for sale. Since carrots are pollinated by insects we need to introduce insects into the tent to pollinate them. Flies are good pollinators!
Ok, back to business…
It was a bit of a risk to rely completely on breeding my own flies, but I had piloted a system last year which seemed to have good success. You can read about the creation of my fly generator here and the pilot attempt here.
For the past few week I have had the fly generator in action as the carrots begin to flower. I simply put the fly generator out with either salmon or chicken pieces on hot days to attract flies. I had good luck collecting flies at various locations around UBC Farm, with the best collecting happening around the compost pile and an irrigation pit.
Once I trap the flies in the generator I take it to the isolation tent with the carrots and release them. I seem to catch about 5 -15 flies each time. It didn’t seem like a lot to me, but after a few loads they do add up.
I was visiting the tent today and could see a lot of fly activity inside. There were flies on many of the umbels which had open flowers, which is what I am looking for. Pollination activity in the tent was as active or more than the control plot outside the tent.
Further, the meat which I used to attract the flues is now teeming with maggots so I have buried that in the enclosure so they can complete their lifecycle and become flies while the carrots are still in flower.
It has been relatively little work to capture the flies. I just need to be sure to put out the fly generator then check it periodically throughout the day. So I do other activities at the same time.
As it stands now fly activity looks pretty good so I won’t capture anymore unless I see a dip in the population. I will check on the enclosure at least twice a week and if the population does decline I can always capture more flies.
And here are the maggots…