Spinosad – an organic control for aphids and how to prevent apple maggots.

Fruit trees

It’s a banner year for aphids and its time I sprayed my plum trees again.  Our little place here is entirely organic and we go out of our way to keep it like that.  So when I spray I will be using a product that contains Spinosad.

Spinosad is a microbe discovered in the soil at an abandoned rum factory.  It’s a broad spectrum product, meaning it will kill a wide variety of insects.  The makers claim it will not harm beneficial insects because beneficial insects don’t eat the leaves.  I always take these claims with a grain of salt but I can say that after spraying for aphids I still find lady bugs living in the trees.  It is certified as an organic product.

A newly born aphid (yes, it is called an aphid – we get a private chuckle at all the folks who come into the greenhouse and call them afis.)  becomes a reproducing adult within a week and can produce five new aphids daily for up to 30 days.  Because the life cycle is one week, it is that cycle we are attempting to break.  When using spinosad I begin spraying immediately after the blossoms have dropped from the tree.  I don’t wait to find aphid because I already know these trees are so prone to them.  These are the only trees I spray.  By waiting until after blossom fall you avoid impacting the honeybees.  Without the blossoms the bees won’t be visiting the tree.   This is important not just because I keep bees, but because of all the benefits the bees provide for the rest of the garden and really, to the environment in general.

Back to spraying.  When using spinosad you want to spray on the same day, three weeks in a row so the reproduction cycle of the aphid is broken.  It works well.  For those of you making the switch from chemical sprays to organics, a new mindset is required.  With the old chemical sprays we all saw “the kill” pretty much immediately after spraying.  This won’t be the case with organics so don’t become frustrated.  Organics work best if used before an infestation is on a full scale breakout.  Therefore you want to stay ahead of the curve on plants you know from experience are going to have a problem.  Rain keeps aphid from moving about as they normally would, so aphid are not normally as big a problem in a wet spring, but a dry spring like this year means they can do as they please and they have been a doin!

Apple Trees – A lot of people wonder how to control apple maggots.  Because the health of the tree is not threatened I refuse to spray my apple trees.  An occasional apple with a worm is perfectly acceptable.  Apple trees are quite productive and it’s not realistic to expect to avoid having some worms in your apples.

So what’s the best solution to controlling apple maggots?  Trap them.  I always understood it was a moth that was responsible for the worms in my apples and so I put up traps to catch them.  Well, I never caught a moth and still had worms in my apples.  Low and behold there is a fly that causes the problem.  Apple maggots overwinter as pupae in the soil.  When the flies emerge in late spring or early summer they are immature and must first feed on the honeydew produced by aphid or scale before they are ready to mate.   One more reason to control those aphids!  The flies then lay eggs under the skin of the apple and leave a pheromone so other flies won’t lay there, thus causing the next fly to move on and infest another apple.

I’m sure that in some parts of the country a moth is responsible for the worms folks find in their apples, but if you have tried the moth traps and still find worms, I suggest you get the Red Sphere fly traps.  They look like a large, red candied apple and are reusable.  You simply coat them with a sticky product called tangle foot and hang them in areas away from your fruit trees.  I couldn’t believe the number of flies they caught when I first began to use them.  (These are not house flies by the way.)  They really do work, are safe and very simple to use.

So if you have fruit trees, these are a couple ways to control the pests they get without using chemicals.  Other organic means to pest control are neem seed oil, pyrethrum,  which comes from the chrysanthemum plant and horticultural oil.  Good luck with your gardening and my your fruit all grow deep voices.


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