Does your heart sink when you see a favorite plant covered with tiny insects exuding a sticky gop, perhaps accompanied by a black dust? You can see that the insects are sucking juices from the plant and you know that these unwelcome visitors means disaster and maybe worse. Take heart; you probably have an aphid infection; certainly not good news, but usually fairly easy to eliminate. Aphids are unpleasant and can hurt your garden plants but knowing more about them will help you deal with them more effectively. Here are eight interesting facts about aphids.
1. There are over 4000 different kinds (species) of aphids about 150 of which cause problems for crops and garden plants in the United States.
2. They come in many colors including green, brown, black, pink.
3. Some kinds only eat a specific kind of plant others like many different kinds of plants.
4. Aphids suck the liquid from the phloem tissue of the plants. This liquid, also called sap, contains the nutrients that nourish the plant. It does not contain enough nitrogen for the aphids so they consume excessive amounts and secrete a sticky, sugary substance known as “honeydew” that is the food for a sooty mold that often grows on it.
5. Ants also like the honeydew, which is rich in carbohydrates, and some kinds of ants live with aphids in a mutually beneficial relations; the ants give the aphids protection and the aphids provide honeydew for the ants; some ants even stroke the aphids with their antennae to stimulate the production of the honeydew!
6. Aphids can damage the plant by depriving the tissues of vital nutrients as they take the sap and by spreading viruses. In addition, some the saliva of some aphids is toxic to the plants they feed upon and cause the leaves to be deformed or puckered.
7. Aphids reproduce asexually in the spring when females produce eggs without males. A single female can produce many billions of descendants by the end of summer. In the fall, aphids reproduce sexually producing eggs that over-winter and hatch in the spring to begin the cycle over again.
8. The natural enemies of aphids are ladybugs, parasitic wasps, lacewings, hoverfly larvae, aphid midge larvae, crab spiders and some fungi. If you have ladybugs around, great, but buying them will probably not work as the kind you buy will fly off before they make any impact on the aphid population.
So, how DO you get rid of aphids? In most cases washing them off with a strong stream of water from a hose will solve your problem. Check your plants daily as you may have to repeat the water spray treatment several times. If that doesn’t work there are other options.
If a large leaf, stem, bud etc. is effected, remove the infected part.
Spray a solution of 1 tablespoon dish or laundry detergent in a quart of water being sure to cover the underside of the leaves.
Commercial summer oils and insecticidal soaps can be used according to directions and again, make sure that you spray the undersides of the leaves. Summer oils can burn depending on the plant and the temperature at which you apply the soil so read the directions carefully.
There are many commercial insecticides that will do the job; check your local garden shop for those that are acceptable in your state.
Of course the best preventative is good gardening practices. Keep the plant healthy with proper light, nutrients, and water. Be careful not to over fertilize as new grow tends to be weak and very attractive to aphids.
Karen Meyers
Great tips! Have you tried that Safer Brand Tomato and Vegetable Insect Killer yet? The site says it’s OMRI Listed and compliant for use in organic gardening, which is a good thing since I’m trying to grow organic tomatoes.
Brandon,
I avoid using any kind of insecticide if possible and a stream of water usually does the trick with aphids.
Karen
Agreed. Aphids can’t generally return to a plant once knocked off. And the simpler the soap the better. I’d probably only use Seventh Generation or something similar when going this route.
Of course, soap water works by breaking down the water-resistent covering of most insects and causing them to drown. So what kills an aphid will kill any other insect or spider if sprayed – beneficial or not.
Marc,
Good point about soap killing other insect, beneficial or not. I always try water and hand picking insects before any other method but unfortunately there are some insects that can only be eliminated by the harsher methods. I also consider how great the damage will be if the insect remains and I have learned to tolerate some insect damage in order to avoid spraying. For example, thrips get my roses but they don’t threaten the life of the bush and they ultimately disappear, so I tolerate them. If I were showing roses I would feel differently but for me tolerating them works.
Karen
How on earth can you say ladybugs don’t work?! It only takes a few to take down a huge population of aphids, it’s amazing to see them at work and spraying insecticides won’t kill all the aphids but it will prevent the beneficial insects from doing the job nature gave them.
Lady bugs are great insect predators but there are many different kinds of lady bugs and the ones you buy tend to fly away to find their own new home.