06 Aug Aphids Make for a Sticky Summer and Stressed Trees

That sticky stuff all over everything this summer is from aphid infestation in Austin's trees. Aphids (also called plant lice, which makes them seem even more charming) are a pretty normal part of spring and summer in Central Texas and are usually kept in check by beneficial insects like lacewings and ladybugs. This year, unfortunately, it looks like the problem will persist until cooler temperatures and rain bring our beneficial bugs back.

In the meantime, aphids are pretty much sucking the life out of our trees. Stressed trees will be sticky or may be dropping their leaves, and new growth may look stunted or curled. You may also see black sooty mold or lots of ants. Check the backs of the leaves to find the offenders: small yellow or green soft-bodied bugs. Other nasties like mealybugs or whiteflies may move in as well.

The Natural Gardener says you can help your trees by thoroughly spraying the leaves with a heavy stream of water. Just two caveats: spray early in the morning and repeat three times a week for at least two weeks to make sure your treatment is effective.

If your trees are severely infested, you can spray with insecticidal soap or neem oil – both organic and both available at any of our local nurseries. You can also make your own insecticial soap spray:

• 1 tsp liquid soap (NOT detergent! Look for brands like Ivory, Fels-Naptha, Dr. Bronners or castille soap) to 1 quart water

• Optional: garlic or hot pepper

Finally, support your trees with regular deep watering and with compost tea or liquid seaweed to help them deal with stress.

Once temperatures drop out of the high 90s or it starts raining, keep an eye out for beneficial bugs on your plants — especially the larvae, which eat a whole lot more aphids than the adults do. Once you see them, stop spraying, because insecticidal soap will kill the good guys, too.

Check these sources for more info on aphids and DIY insecticidal soap spray:

http://tennzen.blogspot.com/2009/05/aphids-and-homemade-insecticidal-soap.html

http://forums2.gardenweb.com/forums/load/organic/msg0811021528979.html