Forest gardening and the Drosophila fly

Hi all!

I am so lucky! I have received an offer to take care of an acre of really good land, for the next 15-20 years or so. Then it will probably be developed.

Between jumping up and down from joy, I am also thinking about what to do with it. I'd love to grow a food forest in part of it and use the rest to make hay. But the drosophila fly has recently been a real problem in my region, destroying tons and tons of fruit in conventional orchards. Will a food forest be able to ward off this pest? Or is it not worth investing a lot of money and time into building a food forest under these conditions? What do you think?

By the way, the land is quite a bit lower than where I am, and on a south-facing slope. Probably zone 8 or so. There are no orchards right next to it, but only woodlands and hayfields.

Monica, congratulations on getting access to land.

I think you should be able to grow a food forest, you just need to be careful what you plant and how you manage it.

Drosophila prefer rotten fruit to anything else, so don't let fruit rot. If you can't harvest it find someone who can. Limiting their favourite foods will limit the population, so there will be fewer to go after the fresh fruit.

Knowing the life cycle of drosophila might be helpful. The ideal temperature for them is 25C. At this temperature they require 9-11 days from being laid as eggs to being adults flying around. at this point they an live 35-45 days. Colder temperatures will slow this down.

Plant species that they will have difficulty getting inside of while fresh. Most apples will have a waxy skin, as long as this is not punctured Drosophila will not be able to get through. Think nuts, tree nuts should not be attractive to flies.

Avoid soft fruits and berries, if they do not have a tough outer layer the flies can lay eggs on them and they will not last. If the flies are brought under control you can always plant these a few years down the road.

How well can the wind get to this piece of land? The wind does wonders to keep the mosquitoes away here, I don't think drosophila would tolerate too much wind either.

Best of luck on your future food forest.

Thank you, Leora!

I was kind of hoping to finally be able to grow figs, apricots and peaches in USDA zone 8, since I can't grow them at my altitude. But of course, you're right. It would be safer to grow fruit with a harder peel, like apples.
I don't know about the wind, yet. But I imagine that the property is pretty well protected by the woodlands.
Thank you for your other tips, also!

Monica, you are talking about drosophila suzukii, correct?

I'm told a non-synthetic way of protecting an orchard are bottles with a fluid mix that attracts the fly installed at about 200 bottles per hectare (one per 50 m2, ie. 7 x 7 m square).

Plastic bottles with holes no larger than 4 mm to avoid bees getting trapped.

The mix:50% water, 40% apple vinegar, 10% red wine, a tablespoon of sugar and a drop of odorless liquid detergent.

I copied this from an experienced american blueberry growser in Slovenia where we're currently entering the battle with drosophila.

See also: http://www.sciencedaily.com/releases/2015/06/150622071737.htm

You mention that your land is possibly in zone 8. If that is correct, note also that high temperatures above 30 C are said to make male flies temporarily sterile.

I actually did research on Drosophila while I was in college! Most of what I know, that would be useful, has already been stated, but I would like to elaborate and provide some tips;

To break the lifecycle, you could allow some livestock to clean up fallen fruit. I think goats or a donkey would be a good choice. You just have to make sure the trees are mature enough to withstand some browsing. Chickens would be great for smaller things like berries. They will eat the larger stuff but I bet they would leave some waste behind, which would probably contribute to the problem.

As stated, drosophila aren't the strongest fliers and are sensitive to wind. Wind could be artificially simulated with fans. You could even create traps by placing window screen on the front of a fan. The flies will get sucked in through the back and dehydrate in the screen.

Traps like the one described work great for fruit flies. I made a trap that was designed for mosquitos, basically sugar water with yeast to create C02, and all I caught were thousands of flies. I also inadvertently made a trap out of jalapeno scraps. I was going to save the seeds and noticed within an hour there were tons of flies on them. Added some water and a drop of soap and they were all over it.

Good luck!

Yes, I'm talking about drosophila suzukii.

Thank you so much for all your tips, you guys are great! I will definitely try them.
I don't know for sure whether the land is really in zone 8, I will have to do some further research. But that is good news, the fact that male drosophila flies get sterile in temperatures above 30 degrees Celsius.

Be very careful introducing goats or sheep into a forest or orchard - they can quickly girdle trees and kill them. I have lost many trees this way from sheep getting into my plantings without my noticing until it was too late. Just a few minutes gives them enough time to do fatal damage.

Ok, thank you for the heads-up, Tyler!