Insider's List
of Gardening Tips and Events

April, 2002

Tips

www.sweettomatotestgarden.com

IT'S APHID SEASON - OH BOY ! ! !
and the little monsters are back on my roses in full force


So , , , where do they come from ? and how can I get rid of them FOR GOOD ? ? ?

The remarkable life cycle of aphids helps to explain how they can quickly appear in large numbers. In the temperate climates of spring, female aphids called "stem mothers," emerge from "overwintering" eggs. These plump, distinctive-looking aphids do not need to mate to reproduce. How about that? These characteristics contribute to the tendency of aphid populations to "explode." When the weather is warm, many species of aphids can develop from newborn nymph to reproducing adult in 7 to 8 days. Because each adult aphid can produce up to 80 offspring in a matter of a week, aphid populations can increase pretty PDQ (pretty darn quick).

"Stem mothers" give birth to live daughters, and these offspring give birth to more live daughters - all without the need of mating. The swiftly growing female aphid colonies cluster around the stem mother and continue to multiply long after her death. This 'family' is what you see on your buds and tender new growth. At the end of the season, aphids begin to produce both sons and daughters. When these males and females mature, they mate and the females lay eggs on bud scales or bark to "overwinter" and begin the cycle again. So, now you know where they come from, I HAVE BEEN RAISING THEM ! !

Signs of an aphid infestation include honeydew or sooty mold on leaves, yellow spots on upper leaf surfaces, cast skins on leaves, curling of leaves, and distortion of new growth and ants on your plants. Argentine ants love honeydew, and to ensure a continuing supply, they protect aphids from their natural enemies. When this happens, aphid management must include ant management.

WHAT'S A PERSON TO DO TO GET RID OF THEM
OR AT LEAST CONTROL THE POPULATION ?

Wipe off or prune away colonies of aphids from leaves and buds.
Use a forceful stream of plain water to wash off aphids and honeydew.
Use insecticidal soaps to kill aphids on contact and spare the beneficials such as lacewings. These products do not leave toxic residues.
Use spray (horticultural) oils to control aphids without leaving toxic residues for their natural enemies.
Attract beneficials to your garden by planting a wide variety of flowering plants. The adult forms of many beneficial insects, including parasitic mini-wasps and lacewings, feed on pollen and nectar.
Learn to recognize beneficial insects. Among the most important natural enemies of aphids are the mini-wasps ("parasitoids") that lay their eggs inside the bodies of aphids. These tiny wasps cannot sting people. A parasitized aphid (called a "mummy") looks puffed-up, and its skin hardens and changes color, often to tan, light brown, or black.
Consider buying beneficial insects. Lacewings are more likely to stay in your garden than commercially available ladybugs. Researchers found that lacewings performed better in hot temperatures, while aphid midges and lady beetles were better in cooler temperatures.
Buy beneficials before aphid numbers are high. If you have an aphid emergency, first use soap or oil sprays to reduce the population. Then, if necessary, release natural enemies. On the other hand, don't purchase beneficial insects before you have aphids. You will be releasing them into your garden to starve.

The least-toxic pesticides used against aphids include insecticidal soap, horticultural oil, and botanical insecticides such as neem or natural pyrethrums.

Horticultural Oil, Dormant Oil suffocates certain pests, such as aphids, mites, mealybugs and scale. The difference between 'summer', 'verdant', or 'growing season' oils and 'dormant oils' is the viscosity. Dormant oil is thicker, summer oil is thinner, which may just be the rate at which it is mixed with water by the gardener. Both are considered an organic pesticide by many gardeners.

My favorite is spraying them off with the water hose and sometimes a simple mixture of Ivory Dishwashing Detergent and water, sprayed directly on the aphids. The soap in the solution strips soft bodied insects of their essential fluids, causing them to dry out quickly and die. Because of this drying action, refrain from using this spray directly on your plants. It can sometimes harm them more than the pests would have.

An alternative recipe for the spray is a solution of water, and a squirt of dish soap mixed with hot garlic and/or peppers pureed in a blender. Spray the aphids each time you see them.


Ants are attracted by and eat the secretion left by aphids. When you see ants on the plant, you have aphids.

Apply a product called Tanglefoot in a band around the trunk just above the ground. (Tip: Put it on Duct Tape, not the tree trunk). Also, I kill ants by pouring big pans of boiling water into their home at the first light of dawn, because they're home then. If you do this when they're not home they will just build another home somewhere else in your yard. I use a product called Amdro if the ant home is close to a plant where the roots might get damaged by boiling water.

Visit your local garden center and plant some of the flowers and herbs named in the box on the right where you have aphids. You will brighten up your garden and invite those wonderful beneficial insects to do your dirty work.

So, , , How can I get rid of them for good? I can't. But a few aphids won't ruin my garden. So I will plant more flowers and herbs, that attract the beneficial insects and I'll wipe-off or wash-off the aphids from my plants. I will use dormant oil in the winter to prevent the overwintering eggs from hatching, then wait and see what visits my garden in the springtime.

Plant Beneficials Attracted
Anise
(Pimpinella anisum)
Ladybugs, parasitic mini-wasps, tachinid flies
Basket-of-Gold
(Aurinia saxatilis)
Ladybugs, hoverflies
Bee Balm
(Monarda spp.)
Bees, parasitic mini-wasps, beneficial flies
Coreopsis
(Coreopsis tinctoria)
Spined soldier bugs, hoverflies, tachinid flies
Cosmos
(Cosmos bipinnatus)
Parasitic mini-wasps, hoverflies, tachinid flies, bees
Dill
(Anethum graveolens)
Lacewings, hoverflies, ladybugs, parasitic mini-wasps, tachinid flies
Fennel
(Foeniculum vulgare)
Lacewings, hoverflies, ladybugs, parasitic mini-wasps, tachinid flies
Feverfew
(Tanacetum parthenium)
Hoverflies
Golden Marguerite
(Anthemis tinctoria)
Lacewings, ladybugs, hoverflies, parasitic mini-wasps, tachinid flies
Lovage
(Levisticum officinale)
Beneficial wasps, ground beetles
Painted Daisy
(Chrysanthemum coccineum)
Tachinid flies, parasitic mini-wasps
Sweet alyssum
(Lobularia maritima)
Hoverflies
Tansy
(Tanacetum vulgare)
Ladybugs, predatory wasps, many other beneficials
Yarrow
(Achillea spp.)
Lacewings, hoverflies, ladybugs, parasitic mini-wasps
Zinnia
(Zinnia elegans)
Ladybugs, parasitic mini-wasps, bees