APHID CONTROL STRATEGIES
In the early spring winged female aphids are landing on your roses and fruit trees. These are pregnant and give birth to 50 or more babies each day. Each baby is a pregnant female! These do not have wings. These are not the same as the black aphids that you find later in the season, which tend to be on the undersides of the leaves, are harder-bodied and more difficult to kill.
Watch the aphid population for a few days, and leave your porch light on at night. Leatherwing beetles and ladybird beetles may show up and start eating them (they'll also be attracted to your porch light, so you can tell if they're in your yard). If the population seems to be stable or decreasing your problem may simply go away.
Blast them off daily with water.
This knocks the pregnant adults off and kills them. More vigorous spraying may be needed to knock off the babies, which are more securely attached to the plant.
Spray with any of the following pesticides:
Quick kill of those that are present; will need to be repeated daily. Our hard water reduces the effectiveness of soap sprays. You can make your own spray out of soap that you buy at the store, but it can't be a detergent and we don't have a rate of application to recommend. There is a risk of burning foliage if you make it too strong, so it's better to buy a product which has been tested and labeled for this purpose.
Natural pesticide derived from a Chrysanthemum. Quick kill of those that are present; will need to be repeated daily. Material breaks down immediately. Low toxicity. Toxic to beneficials, but only for a short period.
Chemically created relatives of pyrethrum (several different ones are available). Quick kill of those that are present, lasting for a day or so. Material breaks down in a couple of days. Low toxicity. Toxic to beneficials for a couple of days.
Natural pesticide derived from the Neem tree. Somewhat effective at smothering those that are present. Repels new winged aphids that are landing. Material breaks down fairly quickly. Low toxicity. Moderately toxic to beneficials for a short period. Provide some fungus prevention as well. Very effective on whiteflies.
Very effective at smothering those that are present and any that land within the next few hours after applying. Material breaks down fairly quickly. Low toxicity. Toxic to beneficials for a few hours. This is what we use in the nursery yard.
© 2012 Don Shor, Redwood Barn Nursery, Inc., 1607 Fifth Street, Davis, Ca 95616
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