Is there a danger to combining multiple fruit tree sprays in one sprayer?

Question

I have a few very small apple and fig trees. I planted the apple trees last year and had a huge problem with bug completely defoliating them. I bought some 'Bonide Fruit Tree Spray' and started spraying them with that as soon as I saw leaves start coming out. They did okay at first, but then I started noticing they were being chewed up. Upon closer inspection I noticed several of those little inch worms that hang from the trees.

I'm in SC, so I contacted the local Clemson College Agricultural Extension and asked them about it. He said they were canker worms and that I should use a chemical with 'spinosad' in it. Being very small tree, I can't make a small enough batch of the spray to use up, so I'm just leaving it in my sprayer with the pressure release valve open. If it gunks up the end, I'll just buy a new one. I don't think the spray I have contains spinosad, so I picked up a bottle of concentrate. I asked him if it would be safe to combine them, since I didn't have two tanks. He seemed to think it would be okay. He said to mix it in another container and something about if it wasn't warm, then it was okay to add it in. I don't know if he meant that I should mix the concentrate with some of the poison water I already had to see if it created chemical heat or what.

I want to know if you guys have ever combined sprays like this to ill effect? I can't remember the name of the spinosad concentrate I bought, but it was labeled as affective against canker worms, caterpillars, etc... It only container a very small amount of the spinosad, though. If I do combine them, I think I should probably use the full dose of each to the recommended amount of water.

Answer 1

Spinosad is organic, which means its fine for use on edible plants, means you can still eat the apples at the end of it. Having checked the ingredient list for your Bonide Fruit Tree spray, I'm glad I won't be eating your fruit! I'm assuming there must be something in the directions for that one to tell you when to stop using it, because otherwise, its possible your fruits may contain traces of those ingredients.

I wouldn't mix the two without further clarification - its not clear what the advice 'if its not warm' means - could they mean when the air temperature is warm? Or does he mean if the mixture gets hot?

Lastly, a word about pesticide/fungicide treatments. It seems you've chosen your Bonide spray at random, because it seemed to control most pests, and you did not know what had affected your crops. It may well have been the canker worms that affected them, not something else, but its always best to identify what problem your tree/plant is having, then apply the right solution/treatment for that particular pest. It's better for the plant, it's better for the environment, and most of all, its better for anyone who's going to be eating the fruits.