If you have spent much time in the garden, you are familiar with aphids. These tiny little pests are quite common and quite annoying. In fact, they are so annoying; lots of people call them plant lice. Aphids do more damage to agricultural and horticultural plants than any other species of insect. In fact, one species of aphid almost entirely destroyed the French wine industry in the 1870’s. They also contributed to the spread of the “Late Blight” fungus that caused the Irish potato famine.
Aphids do more damage to agricultural and horticultural crops than any other insect. Photo by Bruce Leander
Aphids have modified mouth parts that allow them to drill directly into the phloem and extract all of the rich carbohydrates and sugars that it needs from your plants. Aphid damage on plants can lead to decreased growth rates, curled leaves, brown spots, low yields and even death. To make matters worse, aphids are known to spread many different plant viruses. For example, the green peach aphid is known to spread 110 different viruses.
This rose bud is covered with aphids in all stages of their development. The white things in the pictures are the skins they shed as they go from one phase to another. Photo by Sally White
Aphid also excrete a substance called “honeydew” that is also harmful to plants. Aphids feed on plants the same way a mosquito feeds on you. Once they “tap a vein” there is so much food available, and it us under so much pressure, that the unused sap passes through their bodies and onto the plant’s foliage. This forms a sticky, sweet covering on stems and leaves that is a perfect host for mold and fungus.
Close up of aphids in various stages of development. Photo by Bruce Leander.
While there are lots of insecticides that you can spray to control aphids, organic control is usually just as effective. Believe it or not, the most effective tool you can use against the aphid is water. Aphids are soft bodied pests. A good hard blast of water can actually cause the aphid to burst open. Even if it doesn’t burst the aphid, it will knock them to the ground. The ground is a very bad place for an aphid. There are lots of things down there that will eat it. Also, since most cannot fly or crawl very fast, they will often die from exposure before they make it back to your plant.
Effective control with water in not a “one and done” job. If you want to keep aphids in check you are going to need to spray every three or four days. Also, since aphids hide under leaves at night and during the hot part of the day, you need to spray upwards from the bottom of the plant. This is very difficult to accomplish with a water hose. Luckily there are tools out there that can make this job easier and more effective.
As you can see, my roses are infested with aphids again this year. Photo by Sally White.
The best tool I have found is made right here in Texas. It is called the MiteyFine sprayer. The MiteyFine sprayer is essentially a metal tube with a special nozzle that is designed to apply the right amount of pressure (and use the least amount of water) needed to kill aphids. MiteyFine comes in 46” and 58” lengths. The light weight shaft makes it easy to handle and the design ensures that the water finds the aphids that hide in those really hard to get to places.
The MiteyFine sprayer is the most effective tool I have found for organic control of aphids. Photo by Bruce Leander.
I have met several people that are skeptical that water alone can control aphids. In fact, just yesterday I was telling a friend that runs a landscape business about the MiteyFine sprayer. He asked “How do you mix the orange oil in with the water?” No matter how much I swore that water alone was enough, he just didn’t believe me. If you are like my friend, and you feel like you have to spray something on bugs, then you are in luck. Orange oil, neem oil and lantana oil are organic insecticides that can all be sprayed on active infestations with great result. These natural oils kill by clogging the pores that the insects use to breath. However, just like water, you need to spray every few days and you need to spray under the leaves. Be aware that there are some predatory bugs that eat aphids that will also be killed by any oil application.
Lady bugs and their babies are voracious aphid predators. Photo by Bruce Leander.
Lady bugs are another organic aphid control measure that I hear a lot about. While it is true that lady bugs eat a lot of aphids, you would need a whole lot more of them than you can afford to control a good infestation. I have lots of lady bugs in my gardens. However, I still have lots of aphids all over my plants. I am not saying you should not buy and release lady bugs in your garden. Just be aware that they are not the panacea they are made out to be.
Ladybug larvae are often called “aphid lions” because they eat so many of the pests. Photo by Bruce Leander.
Even though aphids are a nuisance, there is no reason to let them ruin all of those beautiful plants that you have worked so hard to grow. With a little observation and a little perseverance, you can control your aphid problems with some very effective organic tools.
Ladybugs lay their eggs close to an aphid infestation. The larvae begin to feed on the slow moving aphids immediately. Photo by Bruce Leander.