How to get rid of aphids on birch trees
Aphids on Birch Trees | Home Guides
By Tarah Damask
Birch trees (Betula spp.) are deciduous plants that grace the home landscape with showy bark and a variety of sizes. Gardening with birch trees appropriate to your region such as the river birch (Betula nigra), which thrives in U.S. Department of Agriculture hardiness zones 4a to 9a, is typically a problem-free experience. However, though these plants typically offer resistance to pests and diseases, aphids occasionally make an appearance. Simply snap into action and manage the infestation quickly to keep your trees strong and healthy.
Preventive Care
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Maintain consistent care habits to promote healthy trees capable of avoiding and recovering from pest problems. Grow birch trees in areas of the landscape that offer full sun to partial shade for best development. Birch trees prefer moist, well-drained, acidic soil but tolerate periods of wetness. However, birches perform poorly in drought. Irrigate frequently to maintain moist soil but avoid creating waterlogged conditions.
Planting birches in areas of partial shade protects them from decline that may occur from exposure to hot temperatures and full sunlight. Prune low branches as needed to allow movement beneath the tree.
Aphids
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Birch trees are susceptible to a variety of aphids, "sucking bugs" that feed on plant tissue fluid. Measuring 1/16 to 1/8 inch in length, aphids display a variety of body colors, including but not limited to green, black, purple and red. These teardrop-shaped insects secrete a sticky, sugary substance called honeydew while they feed on birches. The honeydew falls onto surfaces below, such as leaves. Honeydew often results in the growth of a black-hued fungal disease known as sooty mold.
Effects
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Minor aphid infestations of birch trees result in little to no apparent damage. However, major infestations lead to malformed, swollen or yellowed leaves and stunted shoots. Leaves and shoots may die but an entire birch tree is not likely to die from an aphid problem.
Though the sooty mold growing on birch trees does not directly harm them, it does block out sunlight necessary for proper development and function. In addition, the sooty mold is unsightly. Both honeydew and sooty mold may call for clean-up if the tree is overhanging a home, sidewalk or driveway.
Solutions
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Though aphids and subsequent sooty mold cause alarm, "usually aphids don't warrant treatment," according to the University of Illinois Extension. However, in the case of moderate to severe infestations, control measures are necessary. Begin by releasing natural enemies onto the birch tree. Natural enemies, also known as beneficial insects, kill pests but do not harm garden trees. Purchase enemies such as hover flies, green lacewings or parasitic wasps from garden supply stores. If management with natural enemies proves insufficient, apply a low-toxicity botanical pesticide such as horticultural oil. Saturate the tree for effective control.
References
- University of Illinois Extension: River Birch
- University of California Statewide Integrated Pest Management Program: Birch — Betula Spp.
Family Betulaceae - Colorado State University Colorado State Forest Service: Aphids on Shade Trees and Ornamentals
- University of California Statewide Integrated Pest Management Program: Aphids
- Ohio State University Extension: Aphids on Trees and Shrubs
- University of Illinois Extension: River Birch Aphid
Writer Bio
Tarah Damask's writing career began in 2003 and includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum and articles for various websites. Damask holds a Master of Arts in English and creative writing from the University of North Texas.
Ask Mr. Burger – What Is Wrong With My River Birch?
River birch is a tough and adaptable native tree that is also a popular landscape plant. There a three common indicators however that can indicate something wrong is going on with your tree.
1) If you notice some of the leaves on your river birch have become thickened, distorted, or discolored in the last few weeks don’t be alarmed. While caused by a type of Aphid, these symptoms are not a sign of serious damage and can even be an indication of good things to come to your yard.
2) If you’ve noticed leaves that look like they’ve been chewed on or caterpillar-like insects on your river birch; these are most likely larvae of the Dusky Birch Sawfly. These 1 inch long, yellow-green bodied, black headed larvae, feed in groups along the leaf margins, eating their way to the center vein. Adult sawflies lay eggs on birch leaves in early spring. The larvae that emerge to feed upon the birch leaves until fall, when they spin cocoons and drop to the ground to spend the winter.
3) If your birch tree exhibits yellowing leaves with sparse foliage at the top of the tree, branch or twig die-back and increased side growth on lower branches; you may have a Bronze Birch Borer which is the larvae of an iridescent olive brown beetle.
You may also find D shaped holes and ridges on the tree truck and the branches. For about 6 weeks in the summer, the adult beetles lay their eggs in the bark crevices, usually near a wound. The larvae that hatch and bore into the wood of the tree just beneath the bark. The feeding and tunneling of the larvae stop the flow of water by cutting the conducting vessels in the tree thereby causing twig die-back. Weak, young or newly transplanted trees are most affected and may die.
Following are Mr. Burger’s thoughts on what to do in each case:
APHIDS – A common spring pest, aphids are small soft bodied insects sometimes referred to as plant lice. Size wise, most aphids are little larger than a grain of rice and come in many different kinds and colors. Like many pests, most aphid species are adapted to feed on a narrow range of plants and will not spread to everything in your yard.
Aphids feed on plant sap with straw like mouth parts. On ornamental plants, their feeding can cause leaves and stems to become twisted or distorted, but rarely leads to serious damage. As they feed aphids secrete honeydew, a sticky sweet substance that can attract ants and wasps. Black sooty mold, a harmless fungus, often grows on the honeydew, causing aphid infested plants to appear dirty or sooty. Black sooty mold does not damage plants and can be washed off with water or horticultural oil.
The specific type of aphid that feeds on river birch foliage is known as the spiny witch-hazel gall aphid. In the spring this aphid feeds on river birch leaves. In early summer it moves on to witch hazel foliage, but will not infest any other plant. When spiny witch-hazel gall aphids feed on river birch the leaves become crinkled and discolored, with pink corrugated ridges. If you look on the underside of affected leaves you will see the aphids tucked into the ridges.
River birch trees will shed most of the leaves these aphids feed upon, but they quickly grow new leaves and no lasting harm is done to infested trees.
This type of damage is often referred to as cosmetic, since it causes no serious injury, and does not require treatment. Even better, the aphids that cause this damage attract hundreds of ladybugs and other beneficial insects to your yard that will persist long after the aphids have gone.
Aphid populations build up very quickly and it usually takes a week or two for ladybugs to find them so be patient if at first your aphid infested plants lack ladybugs. Each ladybug will eat hundreds of aphids so it does not take many to wipe out even a sizable aphid population.
Control of Aphids – If you just can’t wait for Mother Nature; aphids can be controlled with the following insecticidal sprays: Malathion, Thuricide, Fertilome Triple Action Plus, Spinosad, Insecticidal Soap or Bayer 3 in 1.
Dusky Birch Sawfly – Although this insect looks like a caterpillar, it’s actually the larva of a wasp relative, the sawfly. While this insect can cause a lot of foliar damage, they only exist for a short period of time and the tree will drop and regrow new leaves.
Control of the sawfly “caterpillar” – the larvae are a common food favorite for local birds so they can help or the caterpillars can be controlled by simply hand picking them off or by spray washing the larvae off the tree with water or in the case of large numbers, can be controlled with the following insecticidal sprays: Malathion, Thuricide, Fertilome Triple Action Plus, Spinosad or Fertilome Systemic Drench.
Bronze Birch Borer – When birch leaves yellow in the spring/summer and branch or twig dieback first occur; it’s important to cut out and destroy all dead and dying branches. If the tree is small enough to reach the top safely; spray the tree and two more times in two week intervals with an insecticide that contains permethrin like Hy-Yield’s 38 Plus, to kill the young Birch Borer larvae before they burrow into the wood. If the tree is too large, you may want to call in a certified arborist to spray your tree. Maintain good tree vigor by watering and fertilizing regularly.
We hope you find this information helpful and can use it to keep your Birch tree looking great for many years to come.
Partial contents of this post were written by Charlotte Glen and information taken from “The Ortho Problem Solver, 7th edition” book.
How to defeat aphids?
Last year I planted my own garden in my dacha. Recently I went, looked and saw a not very pleasant picture - the leaves and tops of the shoots are twisted, the leaves themselves no longer grow, and there are many small green “fleas” inside. I understand that this is aphids. How to deal with it?
Alexey Mikhailovich.
Description of the enemy and his ally
A small, about a millimeter, insect, and there is a lot of harm from it - trees, shrubs, vegetables and even flowers suffer. But usually we remember this pest when it has already brought tangible harm. Which, by the way, many underestimate.
Aphids suck the juice from leaves, stems and buds.
In the affected plant, the leaves, buds and shoots are deformed, their growth slows down, and the fruits often do not ripen. Quite often, a weakened plant dies in winter. In addition to direct damage, the aphid spreads viral diseases, and black soot fungus develops on the sugary secretions of the insect.
Now, carefully inspect all seedlings purchased for the garden - they may well have aphids. If it is found, immediately destroy the pest, otherwise it will occupy your garden and fighting it will require a lot of time and money. If you see ants running around the plant, be sure to check for aphids. As a rule, ants are attracted to honeydew, which is secreted by aphids.
Ants are not just pointers to aphids. They are her allies. "They act like cattle breeders." That is, they breed it and take it away through the trees. It is believed that they can remove it for the winter, and take it out on plants in the spring. Therefore, the fight against ants goes hand in hand with the fight against aphids
Prevention.
You need to start it in early spring, before the buds wake up - treat shrubs and trees at temperatures above plus 4 ° C on still bare trunks with a solution of karbofos (75 g per 10 l of water) or other permitted insecticides.
Among the preventive measures are those that can be applied almost throughout the season. You can plant umbrella plants - carrots, dill, parsley, fennel and others. In this way, you will lure the main aphid eaters - hoverflies - to the site.
You can also arrange flower pots with wood shavings - earwigs, which also like to eat aphids, can live there. Make bird feeders and birdhouses - they eat aphids in large quantities.
Plant lavender along with roses in a flower bed, it repels green aphids, and thyme, sown next to legumes, protects them from black aphids.
Properly feed the plants - aphids prefer weak or overfed specimens. But besides this, a strong and healthy plant should be planted in a good place where there is enough light and water and good air circulation - all these points are also reliable protection against a small parasite.
Environmentally friendly ways to get rid of aphids
If you use chemicals, along with the aphids, you will destroy its enemies. Therefore, if time permits, use biological agents. They are more troublesome, do not have guaranteed efficiency, but environmental friendliness warms the soul.
During the growing season of plants, it is preferable to use decoctions and infusions of herbs - they are not dangerous for beneficial insects.
Base solution - soapy. Grind 100g of laundry soap (not liquid) and dissolve in 10 liters of water. By itself, this solution helps: the respiratory openings of the aphid are sealed and it dies.
You can strengthen this solution with the help of various additives.
An infusion of garlic or onion is prepared as follows: a head of garlic (onion) is crushed and the mixture is poured with one liter of water. Then add to the soap solution. One head per 10 liters of solution.
To make an infusion of hot peppers, pour 100 grams of fresh fruit with water and boil for at least an hour in a sealed container.
Then leave the resulting "soup" to infuse for two days, then grind the pepper, and strain the solution. Further, this concentrate, immediately before processing, must be diluted with water in a ratio of one to ten..
A few more popular recipes for fighting aphids.
1. Pharmaceutical chamomile (1 kg of raw inflorescences) is soaked in hot water at a temperature of 60 - 70°C for 12 hours. Then we filter and add 50 g of soap. Spray solution is ready.
2. To prepare the next solution - stepchildren of tomatoes (4 kg per 10 liters of water) are boiled for half an hour.
3. Onion peel remedy is obtained by infusing 200 grams for 5 days in 10 liters of water.
4. 300-400 grams of celandine collected during flowering (you need to take the whole plant) or 100 grams of dry infusion in 1 liter of water for a day or boil for half an hour.
5. If 100 grams of dried citrus peels are poured with a liter of water and left for 2-3 days in a warm place, we will also get an agent to combat aphids.
6. If you have tobacco or shag, take 40 g of dry raw materials and insist in 1 liter of water for two days. Then strain and add another 1 liter of water.
7. Grind 400 g of fresh leaves or 300 g of dandelion roots and infuse for 1-2 hours in 10 liters of warm water (but not above 40 degrees), strain and spray.
9. Add any liquid vegetable oil to the soap solution 100 ml per 10 liters of solution.
We used a soapy solution with oil and that was enough. But eco solutions may have to be used more often than chemical ones.
Chemical aphid control
Aphids are easily destroyed by insecticides. In early spring, you can safely use Agravertin, Fitoverm, Actara. kinmix. Spray the plants with a solution of 2.5 g per 10 liters of water. This must be done before the buds open. Now, as well as in summer, affected fruit plants or if aphids have settled in close proximity to them can be treated with drugs - karbofos, rovikurt, mitak.
True, this can be done no later than 30 days before the start of the harvest.
Greenhouse grown tomatoes, cucumbers, peppers can be sprayed with Fitoverm, Actellik, Intavir and Agravertin. Cabbage is allowed to be treated with Actelliquifury.
Please note that if it rains after spraying, the procedure will have to be repeated. Different aphids can also settle on different plants, but the breeding cycle for different species is almost the same, somewhere within 10 - 12 days, although generations per season can grow from 4 to 16.
Based on this, plants must be treated with chemicals at least twice. And infusions and decoctions of herbs are used after 7-10 days 3-4 times per season, but more often.
On white and red currants, you can see red swellings on the leaves. These are damage caused by gall aphids. Before harvesting, you can only pluck the affected leaves and burn them.
The treatment had to be done in early spring with karate preparations, spark, fury, when the buds first appeared.
Red gall aphids can also infect an apple tree. The leaves begin to curl, swell, turn yellow and fall off. Red spots may also form on the fruit. They fight this type of aphid on an apple tree in the same ways as with the usual one.
Daria BOBYR
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How to deal with aphids on fruit trees - folk remedies and effective drugs
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