knock back an insect infestation without hurting fish.

[Robert Wright]

I had an out break of spider mites in the system. the larva were hard to see on the leaves and the mites just hide in the clay pebbles, so I removed most of the plants and got a six gallon pail, put a couple of gallons of really hot tap water in it and scoped up the pebbles in the top three to four inches of the twelve inch deep grow bed and put them in the hot water. that killed a lot of mites and a few earthworms which I fed to the catfish. them I returned the cooled off clay pebbles to the grow bed. I will have to do it again after replanting the remaining plants in the grow bed and removing the remainder of the plants, but I am hoping that I killed off any eggs in grow media to knock them back to a manageable level. By using hot water I am not introducing anything harmful to the fish and by only treating the top few inches I have not decimated the grow bed's ability to filter the fish waste. I'll let you know how it works out.  

[Jonathan Kadish NYC AA Chair]

My experience this winter was that the mites would stay on one plant at a time, in this case swiss chard. I cut off all the leaves at the base of the plant and took them outside. The chard sent  out new leaves and I haven't seen a mite since.

[Philippe Pauvert]

Hi Robert, there is the M5 recipe that is believed to kill most insects:

3 kg of red onions

3 kg chili peppers, the hottest the best

3 kg garlic

3 kg ginger

2 liters industrial alcohol

10 liters waters.

[Rob C.]

I've had some success with a Diatomaceous Earth spray.  But be sure to use food-grade DE because it is uncalcinated.

Mix 3 tablespoons of DE with one gallon of water, and put the mix in a sprayer.  Shake the bottle vigorously every so often while spraying to keep the DE suspended in the water.  Spray it on everything: plants, planters, planting medium, the floor/ground where your garden is located, etc.  When the water evaporates, the particles of DE remain to kill the insects.

DE kills insects by a desiccation, so the insects have no defense against it.  It is harmless to larger life forms like fish and us, but use a mask when working with dry DE.  It is very dusty and can cause silicosis of the lungs if inhaled over long periods of time.

One last thing to remember:  Any area that is exposed to rain has to be sprayed again after the rain.

Good luck!

[George]

knock them off with a hard spray of water.  repeat every other day a few times.

[Alex Veidel]

Mites don't have a larval stage; once they hatch they look like miniature versions of their adult form and are known as nymphs. They reach their adult stage after going through several molts. Adults/nymphs/eggs all hang out on the leaves, although they'll use the media to travel. Are you sure you're dealing with spider mites?