Control of Pests and Diseases in the garden.

[anniefish]

Hi Murray,
I found this article with recipes for treating and preventing powdery mildew. http://www.abc.net.au/gardening/stories/s1484689.htm you might find it helpful.
Anniefish

[Murray]

Thanks Annefish,
The milk I have tried, and it sort of works, but the bi-carb recipe will be getting a run that is for sure.

I will let you know how it goes. Thanks very much.

[Jonathan Dyer]

Hi Murray,

You do understand that both Copper Sulphate and Lime Sulfur are natural products and are the best two products to control powdery mildew. Alternatively you can use molasses as with the milk or bi-carb it has a high pH and reduces the effects of mildew as the bacteria likes a low pH to grow. Both milk, bi-carb or molasses may not fully control it with one application it is always better to use these products as a preventive on a regular basis say every 14days if the risk is high rather than the cure after an outbreak occurs and it is always best to use these products prior to and several days after rain as this is when the major cause of powdery mildew begins.

[Murray]

Hi Jonathan,
I would be worried about the use of copper based products in aquaponics. Copper is a marine killer. Most anti-fouling paints used on the hull of boats are copper based.
They used to be tin based, but tin based anti-fouling was so effective that inside most marinas there was no fish life at all. Every living thing was dead due to the tin based anti fouling paint on the bottoms of the moored boats.
Copper based paints are not so potent as the tin based paints were, but barnacles do not adhere themselves too well to the copper based paints and coatings.

I am very tempted to set up a small system and test the use of the copper based anti fungal treatments and observe the fish over a long period of time. But such a test would not yield enough reliable information. Without proper laboratory testing accurate results could not be known.
The fish in the test aquaponic system may live and look ok, but have high or dangerous levels of copper in their systems, and be unsuitable for human consumption.

[Jonathan Dyer]

G’day Murray,

Yes you are correct Copper Sulphate at a certain dose will kill almost every fish on the planet. However, even in aquaponics you are only spraying the plants even though there is some possibility it may make its way back into the fish tank if you are careful there will be little Copper Sulphate in the water. By mixing a weak (say ½ to ¾ solution) in a hair spray bottle or a small presser sprayer then with caution apply the solution to the plants making sure as little as possible gets on to the gravel bed you should be pretty safe. Yet, if in doubt use molasses on a regular basis to prevent mildew, molasses also has the added advantage in the grow beds to stimulate (as a food source) microbes the worms and nitrifying bacteria rely on to survive similar to what seaweed extracts do, molasses also improves frost tolerance of plants (to what degree I am unsure but it does help).

Are you growing rockmelons in your aquaponic system? If so how are they going?

I think it would take a lot of Copper in the fish to be toxic to humans if the fish are not dead I would find it hard to believe it could be toxic to us, yet, everyone is different a person that is latent deficient in copper could benefit but someone else it may very well be toxic. The only way to tell as you said is a lab test.

[Murray]

Jonathan,
The rock melons did well until all this rain started and the powdery mildew got them, hence my interest in an effective mildew control. I might try the copper based stuff in one bed and try the bi-carb of soda recipe in another bed. See how they go.

[Jonathan Dyer]

Wouldn’t they be better grown in the soil? As one would need say 50 plants to have a good supply of rockmelons a bit crowded in an aquaponic system is it not.

[GaryD]

Hi Jonathon,

A lot of plants are better grown in soil than aquaponics either because of their size (zucchini, eggplant, sweetcorn, sunflowers, etc) or their growing habit (melons, pumpkins, etc) but most of we aquaponicists like to experiment a bit.

Gary

[DuncanC]

Hi Jonathon,

A lot of plants are better grown in soil than aquaponics either because of their size (zucchini, eggplant, sweetcorn, sunflowers, etc) or their growing habit (melons, pumpkins, etc) but most of we aquaponicists like to experiment a bit.

Gary

I agree whole heartedly with you here Gary. I'm really looking forward to getting my system up and running so tha I can try out a myriad of unconventional aquaponics plants! I can barely stop myself from running out the door this very moment and starting to build my system (should be built inside a week and a half).