Sep 14, 2012 – Come For the Sugar, Stay For the View

QUESTION:

It is autumn in New England and holly bushes are being swarmed by wasps, bees and other insects. I believe this is caused by aphid secretions and the holly flowers that bloom at this time. Are there any treatments that will help deter this from happening?

ANSWER:

Yes, the sugary "honeydew" produced in potentially copious quantities by aphids is a major attraction to sweet-feeding insects, and as the weather dries and cools in the fall there may be fewer other options available, making the honeydew that much more attractive. Insects like honeybees, in particular, are trying to increase their stores of honey so they can survive the winter, while wasps and other bees may just be there to live as long as possible. Who knows but other insects may be predators that feed on the aphids or even on the bees and wasps that frequent these plants. 

If you are hoping for some product that will repel the bees and wasps from these plants I think the answer will be "no". While some insecticides may very well be repellent in nature they are not designed as bee or wasp repellents, and none others exist. Your best bet, if the bees and wasps are a problem that must be eliminated, is to eliminate the reason they are coming. Do an inspection of the plants to be certain that aphids are present and producing the honeydew and you then can apply a labeled insecticide to the plants to eliminate them. This will also be likely to kill the bees and wasps, which would be unfortunate given their beneficial behavior. You also could try spraying the plants with a strong stream of plain old water. This will wash the aphids off and at this point in the year probably prevent them from climbing back on. It also will help to wash away the honeydew accumulations. 

If aphids are the problem and this appears to be an annual event, a better approach might be to use a soil-applied systemic insecticide, such as Merit, earlier in the year. The active ingredient will move into the foliage and be there for the season, killing only the insects that feed on the foliage but not affect other insects that walk over that foliage. Be sure to read the product label to be certain holly is approved as a site. 


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