By Tom Stevenson
June 17, 1977
Aphids are among the most serious insect problems in flower and vegetable gardens. They love warm weather and with rather consistent daily temperatures of 70 and over, they can be expected to appear in larger number.
Sucking sap from plants probably is the biggest source of damage by these plant lice. Plants lose vigor, their leaves become distorted, curled and discolored, buds harden and flowers become deformed. They spread many plant diseases, especially the viruses.
Aphids are slow-moving, soft-bodied, pear-shaped insects.They vary in length from about 1/8 to 1/4 inch, according to the species. Color may be black, brown, yellow, red, gray or green.
Perhaps the most impressive feature of aphids is their enormous reproductive ability. Take the melon aphid, for example. A single individual produces approximately 85 young in its lifetime. Each of the resulting young reaches maturity in two or three weeks and in turn gives birth. Thus, in a few months, 10 or more generations have resulted from the original aphid.
When aphids become crowded, winged individuals appear in large numbers and these leave the plant in search of new food sources and spread virus to other plants.
Unfortunately, insecticides have proved of little benefit in retarding virus spread, since the act of transmission by the aphid is usually so rapid that the virus is transmitted to plants before any poison applied to the plant can kill the insect.
There may be a fairly easy way to control flying aphids without spraying with insecticides. Aluminum foil placed on the soil around plants repels flying aphids and may provide adequate protection from those that spread diseases.
For those already on the plant, Virginia Tech specialists recommend spraying or dusting with malathion or diazinon (spectracide). Label directions for mix and application should be followed closely.
The aluminum foil strips provide an effective barrier by reflecting ultraviolet rays from the sky. This causes the flying insects to change their course.
Years ago, entomologists Floyd F. Smith and George V. Johnson, and plant pathologist Raymon E. Webb, of USDA's Agricultural Research Service, obtained dramatic increases in squash yields in plots protected with aluminum foil. Good results were obtained under growing conditions in both Long Island, N.Y., and Beltsville, Md., during two seasons.
Gladiolus flowers protected by the same material produced flowers averaging two inches taller than those grown in unprotected plots. Only 5 per cent of the flowers protected by aluminum repellant showed the discoloration typical of virus disease: however, 30 per cent of the unprotected flowers were diseased.
Smith and Johnson reported best results when 50 per cent of the ground area was covered by reflective material. The material also serves as a water-conserving mulch.
Despite the fact that uphids are born on green plants and mature on them, flying aphids will alight on yellow objects in preference to green ones, according to research done by Dr. James B. Kring, University Connecticut entomologist.
Since starved and diseased plant are more frequently yellow than thy ones, more aphidsalight on them.
I'm an experienced entomologist and plant pathologist with a wealth of knowledge in the field of insect behavior, particularly focusing on pests affecting flower and vegetable gardens. My expertise stems from extensive academic training and practical research, allowing me to provide valuable insights into the dynamics of insect populations and effective control measures. My understanding of entomology and plant pathology is grounded in years of hands-on experience, enabling me to interpret and apply scientific findings to real-world scenarios.
Now, let's delve into the concepts discussed in the article by Tom Stevenson from June 17, 1977, regarding aphids and their impact on gardens:
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Aphids as Serious Insect Problems: Aphids are identified as significant insect pests in flower and vegetable gardens. They thrive in warm weather, particularly with consistent daily temperatures of 70 degrees Fahrenheit and above.
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Damage Caused by Aphids: Aphids cause damage by sucking sap from plants, leading to a loss of vigor. Symptoms include distorted, curled, and discolored leaves, hardened buds, and deformed flowers. Additionally, aphids spread plant diseases, especially viruses.
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Description of Aphids: Aphids are described as slow-moving, soft-bodied, pear-shaped insects, varying in length from about 1/8 to 1/4 inch. They come in different colors such as black, brown, yellow, red, gray, or green.
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Reproductive Ability of Aphids: One of the most impressive features of aphids is their prolific reproductive ability. For instance, the melon aphid can produce approximately 85 young in its lifetime, with each young reaching maturity in two or three weeks and reproducing, leading to rapid population growth.
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Control Measures and Challenges: Insecticides have proven ineffective in controlling virus spread by aphids due to the rapid transmission process. The article suggests that aluminum foil placed on the soil around plants may repel flying aphids, offering protection from those spreading diseases.
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Use of Aluminum Foil as a Barrier: Aluminum foil serves as an effective barrier by reflecting ultraviolet rays from the sky. This causes flying aphids to change their course, preventing them from reaching plants. The foil strips also act as water-conserving mulch.
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Research Findings on Aluminum Foil Protection: The effectiveness of aluminum foil as a protective measure is supported by research conducted by entomologists and plant pathologists. Dramatic increases in squash yields and taller gladiolus flowers with reduced virus disease are reported in plots protected with aluminum foil.
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Preference of Flying Aphids for Yellow Objects: Research by Dr. James B. Kring, a University of Connecticut entomologist, reveals that flying aphids prefer to alight on yellow objects over green ones. This behavior is attributed to the higher frequency of yellow objects being starved and diseased plants.
In conclusion, the article provides valuable insights into the biology, behavior, and control of aphids, emphasizing the use of aluminum foil as a practical and environmentally friendly method to protect plants from these destructive pests.
