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Sunday, May 18, 2014

My Pomegranate Has Those Little Red Bugs

Q. I have a pomegranate tree planted by birds about 20 years ago. I never had bug problems on this tree before 2011. In 2012 it produced about 150 pounds of pomegranates. In 2013 the tree did not produce any fruit at all. This year the tree is loaded again but it is infested with those little red bugs that I think will turn into those ugly creatures you have been talking about. We don't want to use poisons. Have there been any new developments for control?
A. This particular bug, the leaf footed plant bug, is a growing problem for Las Vegas gardeners. The only way you will have a good crop of pomegranates, and most likely pistachios, is to spray.
Leaffooted plant bug on pomegranate
            The two choices you have are to spray with a conventional insecticide, which you call a poison, or spray with some sort of “organic” spray which I guess you might call non-poisonous.
            Conventional insecticides leave a longer residual on the plant so you do not have to spray as often. Most organic sprays must be repeated more often because they don't have much of a residual or none at all.
            One of the most effective “organic” sprays is soap. You can make your own soap sprays but for most people I would highly recommend buying insecticidal soap already made. The soap used to make insecticidal soaps is less damaging to plants than grabbing scented Ivory liquid and using that.
Safers insecticidal soap
            Insecticidal soaps, to be effective, must be sprayed directly on the insect. They have no residual. When these bugs die from the soap, new ones will come in and invade their territory so you have to re-spray frequently.
            The most effective time to spray soaps is toward dusk when bugs have settled in for the night. Soap sprays are not selective. They will kill any insect that comes in direct contact with your spray, good or bad.
            Organic sprays containing pyrethrum, an insecticide derived from either Dalmatian or Persian chrysanthemums, will probably work well. However, pyrethrum is a poison. Use it carefully and wear protective clothing.
Pyrethrum farmer in Kenya
            Synthetic or manufactured sprays that chemically resemble pyrethrum, which you would categorize as a poison, are probably going to be effective as well. Scientists “tweaked” the chemistry of pyrethrum to give it more “knockdown power” and last a little longer. These are called synthetic pyrethroids.
            Chemical names in the ingredients will say things like “Permethrin” or “pyrethroid”. These chemicals emulate natural pyrethrins but are manufactured and as such are not “organic”. If you decide to go conventional, then look for these names in the ingredients. Make sure the label permits you to apply it to fruit trees.

4 comments:

  1. What actual harm do these insects do? I have a pomegranate tree that is over thirty years old and is prolific in its fruit production. These insects have appeared on the tree in almost all of the 20 years I have lived here and I have yet to see any damage directly attributable to them. I will be very interested in your response.

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    1. In small numbers, they don't cause a lot of problems. In large numbers their feeding can cause fruit and nut drop on pistachios or cause them to form "blanks", no nut inside the kernel. In extreme cases a total loss of fruit and nuts for that year.

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  3. I have the same problem with these bugs on my three pomagranite trees. It is said they could affect some nut trees also, does that include Walnut trees?

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