After 14 months of operating the system I came back to school after Christmas and found what looked like fine sawdust all over my pepper plants. Upon closer examination I found the bugs pictured below. I crushed two entire garlic bulbs put them in 500 mL water with a 5 mL dishwash soap. I have been spraying 2 times daily, Some die, but then keep coming. I spray gingerly with a fine mist trying to prevent too much from dripping into the grow bed. The work room beside the class room smells strongly of garlic.
These guys are called green peach aphids. They didn't look like aphids I was familiar with before, so it was a few days before I actually discovered what they were.
I purchase some Neem Oil extract that definitely kills them more rapidly, but I use it sparingly only on groups of aphids being careful not to let it drip into the grow bed.
Anyone have any experience with such an outbreak and use of Neem Oil extract?
Hi Luther. I've used Neem oil with moderate success. It was a way to control them. I used it sparingly also and I never lost any fish.
I realize you are asking about neem oil. In case you want to explore other options...here is one: You can use freshly brewed worm casting tea at a concentration of 2/3 cup castings to 1 gallon of non chlorinate water and 2 tbsp. sugar. Aerate for 12 - 24 hours (you can even put it in a jar and shake it up once an hour for 12 - 24 hours if you do not have a fish tank air pump to use - be use to take the jar lid off between hourly shaking it). Spray it on plants top, sides and bottoms of leaves. The chitinase the worm castings naturally contain will help rid of the aphids. It attacks the chitin that insects exoskeletons are made of. You can use worm casting tea in any concentration with the plants in the aquaponics system without worry of harming any component of your system.
Best of luck to you as you tackle this challenge!
This pic is of green peach tree aphids from an AP system, about 9-10 days after being sprayed with Beauveria bassiana fungal spores (commercial name Mycotrol -O) This beneficial fungus is fish safe, OMRI approved and definitely does a number on aphids. I took this picture this past spring/summer, but have been using this stuff for quite a while now.
Most of my commercial clients don't have the patience/time to deal with "home-brew" remedies (I happen to quite like a good homebrew remedy that works...but I understand where these clients are coming from)...