Why are the Leaves on My Plum Tree Sticky? (All you need to know!)

Plum trees are grown for their delicious fruits. Some people might face issues while growing these trees.

If you see a sticky substance on the leaves of a plum tree, your tree is probably infested by Aphids. They release a sticky substance called Honeydew.

You’ll also notice that your leaves are curled up and become brown. The infestation usually appears in the growing season and affects only a part of the tree.

Why should you be worried?

Plumtree aphids are tiny pests that are pale yellow to light green in color.

They harm young plumtrees to a great extent!

Cause Sooty mold

They secrete a lot of honeydew. This honeydew attracts ants.

This paves way for fungal development which is popularly known as Sooty mold.

Aphids cause a lot of damage to young plants as they deter foliage development.

They cause loss of fruits and the vigor of the tree. They suck on to the sap of the tree.

It is very hard to get rid of them once they are established in the leaf curls. You should get rid of these aphids as early as possible.

Can aphids kill a plum tree?

Serious infestations will deplete plant resources and may stunt plant growth.

The plant is as good as dead. It will not bear any fruit nor its foliage will grow.

Catch ’em early!

Keep checking your plumtree in the growing season for aphids. If you catch them early, their eradication becomes easier.

They initially suck plant sap from the young shoot. Then they migrate to leaves. Once they hide in the curled leaves, they are pretty safe.

Hang Stick-a-fly yellow cards on young shoots of your tree in the bud break time. If you see any aphids, you have to act immediately.

Let’s see how you can do so.

How do I get rid of leaf curl on my plum tree?

Leaf curl aphids are the culprit. They infect the tree in the growing season and curl leaves so they can shelter in them.

They only affect a branch or part of the tree and the disease takes a month or two to become conspicuous

You may need to act before they get established in the curled leaves.

In order to get rid of the leaf curls, you need to get rid of the aphids.

What is a natural way to get rid of aphids?

If the infection is in the early stages, you can get rid of them by quick hard blasts of water at the affected branches.

Natural ways of control should be preferred as spraying insecticides will not only kill aphids but also kill predator insects. This would make the issue even worse than before.

Let’s look at some natural methods of Plum tree Aphid eradication.

Biological control of Plum Tree Aphids

Biological control is the most ideal way to control aphids. It works well and doesn’t harm your soil/plant in any way.

Lady beetles, Greenlace wings, and Syrphid fly larvae like to munch on plumtree aphids. Spiders eat aphids with a passion.

Introduce these predators in the growing season and you’ll be able to control the spread of plumtree aphids.

Ideally, you should try your best to control via biological methods. Have good patience and it will work.

Organic spray

If you couldn’t control through biological methods, you can always use organic sprays.

You can use a superior type of horticulture oil in the dormant season. Spray the plant in November and monitor the plant regularly.

Read the manufacturer’s instructions before you spray the oil.

If it’s growing season, use Neem oil, non-toxic insecticidal soap, Imidacloprid or Pyrethrins.

Once the bud break starts, treat the affected plant repeatedly to prevent an outbreak of the infestation.

For best results during the growing season, use different sprays alternatively. This assures there is no resistance buildup in the aphids.

DIY Insecticidal Soap

Insecticidal soap is rather expensive, you can lower costs if you follow this simple hack.

Insecticidal soap can be made at home, I tried it and it works well.


Mix 2 tablespoons of Palmolive Green dish soap in a gallon of water. If the infestation is severe, you can increase it to 3 tablespoons per gallon of water.

There has been no damage to leaves after I sprayed this on the plant.

Spray in the evenings for best results. You may need to spray the neighboring plants too.

Note: Spray the plant with water the next day, to rinse unwanted soap off the leaves.

You can spray this solution using a hose-end sprayer, my mother does the same and her plum trees are safe from aphids.

Soapy water should be reapplied every 2-3 days for two weeks.

Using Alcohol to control aphids

Isopropyl alcohol also called Rubbing alcohol can be used to treat aphids. Make sure the one you pick doesn’t have additives.

Alcohol usually comes as 70% in stores. Some are labeled 95%.

You can make an insecticidal spray by mixing equal amounts of water and 70% alcohol. If you have 95% alcohol then use 1 part alcohol to 1.5 parts of water.

Caution: At first, apply alcohol only to parts of the plant. Wait for a couple of days and see if there are any adverse reactions. If all is fine, then you can apply it to all the affected plant parts.

Alternative organic methods

There are other natural methods to control aphids.

  • If you have a severe aphid infestation, dust the plant with flour. It constipates the pests.
  • Cayenne pepper spray: Mix 1-quart water, 1 tsp liquid dish soap, and a pinch of cayenne pepper. This works well if you spray it directly(without diluting it).
  • Diatomaceous earth: Apply it to the affected plant parts. Do not apply this when the plant is blooming, as it may kill the pollinators.

How do I prevent aphids on my plum tree?

I always advocate the prevention of such pests. You will have a healthier garden if you foresee such problems and act quickly.

  • Spray horticulture oil in the dormant season to get rid of aphid eggs.
  • Companion planting: Companion planting helps keep aphids away from your fruit trees. Aphids are repelled by Catnip.
  • Control ants and you control aphids! Wrap the tree trunk with paper or duct tape, creating a barrier between the ants and the aphids. Check this tape often to make sure it’s not clogged with debris.

Other means

You can avoid any and all infestations in your garden by keeping the ecosystem healthy.

Focus on building biodiversity in your garden. Plant yellow and white flowers around your fruit-bearing trees.

These plants attract a variety of predatory insects and you can control pest infestations naturally!

Unhealthy trees attract aphids, so try to make your tree healthy. Add good soil around the tree.

Look around your plum tree. Do you see any plants that might be hosting these pesky aphids?

If you are able to find such a plant then get rid of it. This goes a long way in preventing future aphid infestations on your plum tree.


  • Catch them early. Hang sticky cards on your plum tree branches.
  • Try to control the infestation biologically with predators like Lady beetles, Spiders, and Syrphid fly larvae. Wait for a week or two, you are not gonna see instant results.
  • If the above is not your cup of tea, then spray the plant with herbicidal oils or Neem oil.
  • If an insecticidal soap is handy, spray it.
  • The best way to prevent infestation is not to let ants reach the branches. This can be done by wrapping the tree trunk with duct tape.
  • You may also want to spray horticulture oil in the dormant season. This gets rid of any eggs in the leaves.

I wish you aphid-free plum trees 🙂