When Aphids Attack...

Sat, April 19, 2014 2:14 PM | Anonymous

While babysitting for a Desert Willow tree at the VPA downtown Phoenix office, we came across some visitors on the tree--aphids!  To prevent damage to the tree, it is important to act right away before the aphid population takes over.  Because the tree is still a sapling, we can’t spraying the leaves with a strong stream of water to blow them right off the plant. Another option is to create a spray solution by adding about 2 tablespoons of liquid detergent per gallon of water. Spray this directly on the aphids, which are usually under the leaves or other protected areas. If you’re not a fan of using detergent on your plants, below are some suggested organic ways for pest management to include a recipe for homemade garlic spray.

We did notice a couple days later some caterpillars showed-up to dine on the aphids. Sometimes letting nature run its course is best. 

Try out the suggestions below and let us know what works. Or tells us your solutions--we’d love to know the best way to care for our Desert Willow!   


Organic Damage Control

Keep your plants as healthy as possible, and spray dormant oil to control overwintering eggs on fruit trees. Also, control ants that guard aphid colonies in trees from predators by placing sticky bands around the trunks. Spray aphids with insecticidal soap, summer oil (on tolerant plants), and homemade garlic sprays (recipe below).

Seven Ways to Organically Control Pests


Homemade garlic spray

This all-purpose garden insect pest control spray combines the repellent effects of garlic, onion, and hot pepper with the insecticidal properties of soap: 

1. Chop, grind, or liquefy one garlic bulb and one small onion.

2.  Add 1 teaspoon of powdered cayenne pepper and mix with 1 quart of water.

3.  Steep 1 hour, strain through cheesecloth, then add 1 tablespoon of liquid dish soap to the strained liquid; mix well.

4 Spray your plants thoroughly, including leaf undersides.

5.  Store the mixture for up to 1 week in a labeled, covered container in the refrigerator.  

All About Aphids…

Shiny, sticky leaves of trees, shrubs and garden plants are telltale signs of aphids.  Sometimes they cause damage; sometimes they do not. To keep them from becoming a problem, we need to watch for them and then take action when populations begin to build.  Knowing what to look for and how to deal with them are key elements to controlling aphid populations  

Aphids are soft-bodied six-legged critters that suck plant juices and generally make a nuisance of themselves, especially when their populations explode out of control. They come in many colors. Yellow or light green forms are common in our area, but we frequently find specimens in various shades of red, black and gray. Some have wings and some do not. To protect our plants against aphid invasions, we need to understand them.

Aphids tend to congregate in groups, usually at the growing tips of branches or on the leaves. They have a sucking mouthpart and they feed on the plant’s juices. After using what they need, they discharge the waste, a sticky, sweet substance called “honeydew.” The honeydew can accumulate on the leaves and stems of plants as well as roofs, automobiles, sidewalks, driveways, lawn furniture and other items underneath the tree. It makes the leaf sticky to the touch and gives it a shiny appearance. Honeydew falling from a heavily infested tree can give someone underneath a feeling of standing or sitting in a drizzling rain.

There are various ways to control aphids. Sometimes the best solution is to do nothing.  One or two aphids on a plant is no reason to freak out with the insecticide sprayer. Aphids become a problem only when populations are high and the plant has to battle hundreds or thousands of the pests. The key is to watch the plants carefully every day. I like to give my plants help when I start seeing 10 or more on a medium sized leaf.

The first tool in your arsenal is a strong stream of water. Spraying the leaves with a jet of water can blow a lot of them right off the plants. Aphids remaining on the leaf are often injured and eventually die. Unless the leaves are close to the ground, dislodged aphids will not be able to crawl back into place and resume feeding. In your diligence to get rid of the insects, do not allow the jet of water to damage the plant. That would be self-defeating. Also, some plant leaves are susceptible to sunburn from water laying on the leaf during a sunny day. Early morning or late afternoons are the best time to spray plants.

Another way to control aphids is to use an insecticidal soap spray. If you use a commercial product be sure to follow label directions. If you want to create your own spray solution add about 2 tablespoons of liquid detergent per gallon of water. The soap solution will need to be sprayed directly onto the animal which, again, are usually located on the lower surface of leaves and in other protected places. Because some plants are sensitive to the soapy sprays, run a test on a small number of leaves and search for damage before spraying the entire plant.

Predator and parasite insects are really good at cleaning up some aphid populations. Predator insects feed upon the aphids directly. Parasites are animals that lay their eggs into or on the target aphid so that the hatching young can use the aphid for food. When using commercial insecticides to control any insect pest, always keep these beneficial allies in mind and try to do nothing that would harm them. Some insecticidal sprays will be just as hard on the beneficial insects as they will on the target pests.

Lacewing larvae and lady beetles are particularly good at controlling aphid populations because of their voracious appetites. In fact, when aphid populations are low to moderate, many times these predators will find and consume most if not all of the insects without us having to do anything. I mentioned earlier that I found aphids on Virginia live oak trees. Sure enough, next to the aphids, I frequently found lacewing eggs on their characteristic flexible stems. When they hatch, my guess is that the aphid problem will soon disappear. Parasitic wasps and flies are also excellent in helping keep populations down.

By carefully monitoring susceptible plants and taking correct action, aphid populations can often be minimized or eliminated before plant damage can occur.







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