Cherry trees are prized for their spring blossoms and summer fruit. However, keeping your cherry tree healthy and productive can be a challenge when black aphids infest the leaves and shoots. Left unchecked, these tiny pests can stunt growth and ruin the tree’s appearance.
Understanding black aphids and using integrated pest management (IPM) techniques are key to protecting your cherry tree. This comprehensive guide covers organic and chemical control methods, prevention, and sustainable ways to eliminate black aphids from your backyard cherry.
Identifying Black Aphids
Black aphids, also called black cherry aphids, are small, soft-bodied insects that pierce plant tissue and feed on sap. At only 1/16 to 1/8 inches long, they can be difficult to spot.
Look for:
- Colony clusters on the undersides of leaves or along new shoots
- Curled, yellowing, or distorted leaves
- Sticky honeydew residue that leads to black sooty mold growth
Though tiny, black aphids reproduce rapidly. A lack of natural predators allows their populations to explode, seriously damaging cherry trees. Learning to recognize the signs of infestation is crucial for timely treatment.
Common Places Black Aphids Are Found
Black aphids typically gather:
- Along young stems and shoots
- In leaf veins on the underside of foliage
- In branch forks and pruning wounds
Carefully inspect these areas of your cherry tree regularly. Early intervention can halt exponential aphid population growth.
Damage Caused by Black Aphids
If uncontrolled, black aphids can:
- Stunt new shoot and leaf growth
- Deform and curl leaves
- Weaken branches and reduce fruit yields
- Create sticky honeydew that leads to black sooty mold
Establishing control measures at the first signs of infestation is important to avoid lasting harm to your cherry tree’s health and production capability.
Organic Control Methods
Implementing organic aphid management tactics encourages natural pest control and avoids chemical residues on edible cherry tree fruit. Try these biological, physical, and plant-based control options:
Encourage Natural Aphid Predators
Lady beetles, green lacewings, hover fly larvae, and other beneficial insects prey on black aphids. You can purchase them from garden retailers, but also try:
- Planting insectary plants like dill, fennel, and cosmos to attract native beneficial insects
- Avoiding broad-spectrum insecticides that kill good bugs as well as pests
- Providing water sources which predators need for survival
Seeing these “good bugs” in your yard means your biological aphid control is working!
Apply Horticultural Oils and Insecticidal Soaps
Natural, non-toxic oils and soap solutions can effectively control black aphids through contact killing and by blocking their breathing holes. Practice the following IPM techniques:
- Test soap and oil products on small tree areas first to check for leaf burn
- Spray oils on cool days under 90°F to avoid harming tree tissues
- Apply soaps and oils to the undersides of leaves to target hidden aphids
- Repeat applications may be needed as eggs hatch and new generations emerge
Always follow label precautions and application rates when using pest control products.
Types of horticultural oils and insecticidal soaps
| Oil/Soap | How it Works | Application Tips |
|---|---|---|
| Horticultural oils like neem, canola, or cottonseed | Suffocate aphids and disrupt reproduction | Best applied prior to aphid infestation or at first signs |
| Insecticidal soaps with potassium salts of fatty acids | Penetrate the aphid body covering and cause cell leakage | Works best on direct contact with aphids |
Use Strong Water Streams
Simply spraying aphids off plant foliage with water isn’t effective long term. But a strong jet of water can quickly:
- Dislodge aphid colonies from leaves
- Remove protective “honeydew” coating from leaves
- Allow insecticidal soaps, oils, and other treatments to contact pests
Use this method together with other organic controls for immediate knock down of heavy aphid populations.
Try Physical Barriers
Floating row covers, reflective plastic mulch, or aluminum foil strips can form physical barriers to prevent aphids from reaching plants. Research finds aluminum barriers repel 85% of incoming aphids!
However, barriers also keep out pollinators. Remove covers when the tree blooms, and prune back branches touching aluminum strips so bees aren’t deterred.
Apply Organic Fungicides If Needed
The sugary honeydew residue left by black aphids can lead to the growth of black sooty mold fungus on cherry tree leaves and bark. Applying organic fungicides containing sulfur or copper octanoate can suppress this fungus without using harsh chemicals.
Always read and follow label directions if applying organic fungicide products.
Chemical Pesticide Options
In cases of severe black aphid infestations, insecticide sprays and systemic treatments may offer quicker control than organic methods alone. Use chemical options only as a last resort for best tree health and environmental safety.
Insecticidal Sprays
Insecticides specifically made to target sucking pests like aphids, whiteflies, and leafhoppers may provide temporary relief. Active ingredients to look for include:
- Pyrethrins
- Azadirachtin
- Potassium salts of fatty acids
- Canola oil
For any insecticide products, carefully read and follow all label instructions for personal protection equipment, application procedures, and rates. Never apply more than is directed.
Systemic Insecticides
Systemic insecticides are taken up by the cherry tree and make its tissues poisonous to feeding aphids. Options include:
- Imidacloprid – Applied by soil drench or tree trunk injection. Lasts 1-2 seasons.
- Dinotefuran – Sprayed directly on leaves and shoots. Provides 3-4 weeks control.
Continued use of these chemicals isn’t sustainable long-term. Rotate systemics with organic control measures when possible.
Insect Growth Regulators (IGRs)
Insect growth regulator chemicals disrupt the aphid life cycle rather than directly killing them. IGRs like azadirachtin and pyriproxyfen prevent nymph aphids from growing into mature, reproductive adults. Residual activity in trees lasts about one month.
Rotate IGRs with different treatment types so aphids don’t build resistance. Their unique mode of action makes them ideal additions to IPM programs.
Prevention
While aphid management is ongoing, deterring infestations in the first place through prevention helps relieve reliance on control treatments later:
- Clean up fallen leaves, prunings, and debris to eliminate overwintering sites near trees
- Use tree collars wrapped in aluminum foil to block upward aphid migration from soil
- Paint tree trunks white to reflect sunlight and disturb aphids
- Promptly remove suckers and water sprouts which attract aphids
- Band sticky traps around tree trunks to catch migrating aphids
- Water and fertilize appropriately to keep trees robust so they can better withstand pest pressure
Catching infestations early before they escalate is key. Scout all susceptible trees at least once a week when aphids are active. Home orchard monitoring guides are available from university agricultural extensions.
Conclusion
Left uncontrolled, black aphids can seriously impact the health and productivity of backyard cherry trees. Through integrated pest management (IPM), utilizing multiple tactics like biological control, organic sprays, and prevention, black aphids can be effectively managed without an over-reliance on chemical pesticides.
A seasonal, multi-method approach provides the best protection to keep your cherry tree thriving for years of beauty and bountiful harvests to come. The effort spent safeguarding your cherry’s growing conditions from these tiny pests will reward you with lush growth and plump, sweet cherries in summer.