I have read many times that pesticides cannot be used on the plant component of an aquaponics system because you'll end up with the pesticides concentrating in your fish. I have always accepted this but just started to question it.
If I plan to use a botanical insecticide (BioNeem) as a foliar spray in a raft system then what is the mechanism by which I will contaminate the fish? It will not be a result of overspray since the raft covers the entire water surface. Is the insecticide transported through the plant, down to the roots and then into the water and then the fish?
BioNeem is a naturally derived product - the label states "non-toxic to birds, fish and bees". Does the blanket statement about pesticide use need to be qualified?
Thanks in advance for the clarification!
I think that blanket term don't use pesticides is in the realm of the chemical poison ones. Not organic oil derived from fruit and seeds of a neem tree. Not sure what all is in BioNeem tho?
Just an FYI... Neem oil was shown to give reversible infertility in lab rats. It's also warned of use with pregnant women or children. May also be hard on the liver. So wash good if you use it.
ANY kind of oils = Baaad for fish
ANY kind of soaps = Baaad for fish.
So use common sense when spraying. Protect your tank and media beds from overspray. Use more sparingly than you might in an organic garden blablabla...
It is mainly that you have to be very careful what you use around your fish and bacteria. There are pest controls that are safe for fish. There are others that are organic but not safe for fish. Lots of research is in order.
Keep in mind that many things commonly used may contain ingredients that can be problematic for fish, like soaps or oils. Soaps and oils might not actually be toxic, however, they can kill fish quite effectively since they can coat the gills and stop respiration, so again caution and care are warranted.
Now just because the raft covers the water, does that guarantee that over spray can't get down past the raft? Like water splashing or dripping onto the top of a raft (rain) and rinsing residues down into the water? That is the primary concern over spray or spraying the plants to the point that they are dripping the stuff.
As to Neem, as far as using neem products in the garden, well I know neem is in plenty of products we already use on our bodies so I feel fairly comfortable using neem oil away from my aquaponics system. My understanding though is ti can affect bees too so please don't spray it while the bees are actively working in the area. It might not kill them directly, but it does affect growth and change in insects (stops them from transitioning from one growth phase to the next so there might be some cause for concern about how it might affect hormones in other creatures as well.) But Neem oil is still oil so you want to make very sure you are not allowing it or the residues to drip into your system as with anything containing soap or oil.
Some people have gone to the lengths of removing badly infested plants from the system and carrying them away from the system for treatment and spraying and then letting the treatment dry before returning the plant to the system. Such lengths are probably only reasonable for long term and high value plants that are still small enough to move that way.
Now many people have had some at least minimal success with some home mix stuff, again use caution with the soaps and oils.
The Bacillus Thurgensis products so far seem to be safe for fish, However, use them according to the instructions since they are not a systemic and only work against leaf eating caterpillars that eat some of it from the leaves. (I have seen instances where it wasn't so good to be pouring the liquid into the grow beds which had a negative effect on the bio-filter temporarily.)
There is one other product that I have heard of some in HI using successfully, I think against things like aphids and such but I've only tried it on a couple towers and I had those away from the main system when I did the spraying. Just one use was not effective and the aphids came back and I'm generally too lazy to keep up a steady regimen of spraying so when I see something start suffering from pest problems, I'm more likely to just remove it rather than spend more money/time/effort trying to coddle it.
Keep in mind, I'm doing my growing out in the open, NOT in a greenhouse. I expect people doing greenhouse growing are going to have to put extra effort into certain pest control measures since nature doesn't have as easy access to their space to help them out.
Thanks for the responses - this community is great!
What I'm getting is that the main thing is to prevent stuff getting directly into the water and that transport through the plant is not the issue. I understand that this will probably be a simplistic generalization but I'm already more informed (generally speaking)
(of course if you are using any chemical pesticides that are so systemic that they can be transported through the plant, then eek. There are some pesticides that are systemic like that-as in you might drench the soil and the plant takes it up through the roots to ward off pests and I would strongly caution against using those kinds of things.)
But for the ones most people talk about in organics, the danger is direct contamination of the water and/or media.
Do be warned that there are some rather strong and possibly dangerous "organic" pesticides out there and I would be very careful about using some of them around aquaponics. Just because something is "organic or natural" doesn't mean danger free.
To be safe, I also recommend that any mixing of stuff for use as pesticide spray should take place well away from the aquaponics. Just because you only us a drop of the oil or soap in the spray bottle, that wouldn't make accidentally tipping the jug of soap or oil over into the grow bed safe (don't laugh too hard, I've heard of it happening.)
Here's two links to the MSDS concerning BioNeem.... both ultimately written by Woodstream Corp...
Both clearly state...."may be hazardous to aquatic invertabrates"
So that might not directly apply to fish.... but I'd be worried about the worms in grow beds....
Thanks - I did read the MSDS and noted that warning, but I'm thinking of using it in a raft system so no worries about worms (terrestrial not aquatic in any case)