- UC Marin Master Gardener Events & Classes
Garden Help from UC Marin Master Gardeners
- Farmers Markets
- Help Desk
- Proper pruning of wisteria produces a plethora of blossoms
- Compost for every corner of your spring garden
- Paying attention to mushrooms
- Inviting butterflies into the garden
- Growing in your garden now - blueberries
- What's the best way to plant a fruit tree?
- How to protect plants from frost
- What's that plant?
- Bright spots of color help lift the drabness of the winter garden
- Books for Marin gardeners
- Benefits of School Gardens
- Trees: not just nice to look at
- Dealing with mosquitos
- Epilobium – California fuchsia
- Why bees matter, and how you can help
- Picking the Right Plant for the Right Place in Your Garden
- What's That Plant?
- Keeping Cut Flowers Fresh
- Late Summer Color
- Growing Summer Squash
- Short on space? Containers to the rescue...
- Herbs: tough, attractive, practical
- These plants are true companions
- Companion planting in the vegetable garden
- Get Grounded – Healthy Soil Does Matter
- Mushrooms on the March
- Our Gentle Winters are Good for Vegetables
- Rodents like it Warm
- Know What Makes an Invasive Species Invasive
- California Natives - Plant Like a Native
- Consider a Simple Water-Catchment System and Rain Garden/Bioswale Before Winter Rains Arrive
- Have You Scheduled a FREE Bay-Friendly Garden Walk?
- A Green Autumn
- Rx for Pests: Ants
- Fine Tune Your Garden
- Colorful Drought-Tolerant Plants Thrive in Marin
- Water Restrictions and Recognizing Signs of Water Stress
- UC Researcher Is Helping Plants Survive the Drought
- Summer Is Perfect For Peppers
- Do the Leaves on Your Trees Look Scorched?
- Fine Tune Your Garden
- How to Recognize Drought and Water Stress
- Spring is the Time for Potatoes, Asparagus and Citrus
- Don't Let Stink Bugs... Bug Your Vegetables
- Harvesting Berries
- Water Heroes
- Natural Cold Storage
- Fruit Trees; Why We Treat Them in Dormancy
- Fondness for Old Friends
- What Happens to Garden Bad Guys in Winter?
- Plants that aren't blown away by the wind
- A hill o' beans
- Fruit tree thinning
- Fragrant plants: Add some chocolate or Kool-Aid to your garden
- Top 10 resolutions for Marin gardeners
- Trees with interesting bark shine in winter
- Who says your garden has to be green?
- Plant bulbs now for spring beauty
- Gardener's checklist for fall
- Cover crops boost soil in vegetable beds
- Rx: Living with deer
- Growing berries in Marin
- How to build healthy soil
- Gardener's checklist for summer
- Water-saving tips for the home garden
- Gardener's checklist for spring
- Stop the popping - Controlling hairy bittercress
- How to control aphids
- Brightening up the winter garden
- Selecting a fruit tree
- What to plant and harvest in the winter vegetable garden
- Rain, rain, don't go away
- Gardener's checklist for winter
- Getting rid of rats
- Fall: a time for planning and planting
- Asparagus: spears for years
- Lawn: use it or lose it
- Rx for powdery mildew
- Community Outreach Projects of UC Marin Master Gardeners
- Great Gardening Information
- Selecting Plants
- Marin Master Gardener Independent Journal Articles
- How to Become a Master Gardener
How to control aphids
Moderate numbers of leaf-feeding aphids usually do not cause significant damage in gardens. Large populations, however, can cause leaves to curl, yellow or distort. New shoots can be stunted. As aphids feed, they excrete a sticky substance, called honeydew, which often turns black with the growth of a sooty mold fungus.
An ounce of prevention
Aphids love tender new plant growth fostered by nitrogen fertilizer. Don’t give your plants more fertilizer than they need and apply it in small amounts throughout the season, rather than all at once. If you build healthy soil with compost and other organic materials, you can reduce fertilizer applications.
Check your plants regularly for aphids—at least twice weekly when plants are flush with new growth. Many species of aphids cause the greatest damage when temperatures are between 65 and 80 degrees. Be sure to inspect the undersides of leaves carefully because aphids are often green, blending in with the leaf color. Once aphid numbers soar and cause leaves to curl, it is harder to control them because they are hidden within the leaves, sheltered from natural enemies and sprays.
Ants can be a tip-off
If you see a number of ants climbing up a tree trunk or shrub, check for aphids on the branches and leaves above. Ants like to feed on the honeydew that aphids produce and will protect aphids from predators and parasites. Managing ants is one way to control aphids.
If you see ants crawling up a tree or woody plant, wrap the trunk with a band of fabric tree wrap or duct tape and then apply a sticky material like Tanglefoot to the wrap. Alternatively, place ant stakes or baits on the ground to control the ants.
Here are some suggestions for controlling aphids, starting with the least toxic. Be sure to treat the underside of leaves. Repeat treatments at frequent intervals may be necessary.
- If only a few leaves are affected, you can run a gloved finger along the surfaces, squishing as you go.
- Blast the plants with water from a hose or sprayer.
- Spray with an insecticidal soap.
- Spray with a botanical insecticide containing neem oil. Follow label instructions.
You can leave the job to Mother Nature. Aphids are a favorite meal for many beneficial insects, such as lady beetles, soldier beetles and lacewings. Create a good habitat for these beneficials in your garden, and they will help you manage the aphid population.
Contributors: Faith Brown, Nanette Londeree