How to Treat Leaf Curl

Updated February 21, 2017

Growing plants can be a rewarding pastime until problems begin. Leaf curl is a common condition caused by improper culture, environmental anomalies, diseases or even pests. Tomato leaf curl is an example of a viral disease. Treating leaf curl depends upon the plant species, but once you ensure proper cultivation and site requirements you can turn your attention to disease and pests as possible vectors. If the cause is a virus, such as in berries or in solanaceous plants like peppers and tomatoes, there is no cure. The plants will have to be destroyed and the land left fallow for several years.

Measure the recommended amount of fungicide into the hose end sprayer and turn on the hose. There are many fungicides that work, but a copper-based formula is safe and easy to find. The exact amount of fungicide will depend on the size of your tree.

Spray peach and nectarine trees that are often affected by leaf curl fungus in late fall when 90 per cent of the leaves have fallen off. You may also spray in spring, but be sure to do it before leaves bud or it will be too late to be affective. Many ornamental trees such as oak trees will also benefit from the treatment.

Climb a ladder to reach the highest areas first, if necessary. Saturate the tops and bottoms of the leaves and work downward. Try to apply the fungicide when you will have several hours of dry weather. Use the fungicide annually to prevent leaf curl in these fruit plants.

Rake up leaves and other debris every fall to ensure that any infectious fungal spores do not overwinter in the soil and detritus.

Examine the plants for insects. The likely culprits are aphids and mites. Mites are tiny and can only be verified by placing a sheet of paper under the plant and shaking it. The tiny black specks that fall out are mites.

Treat the plant for the insects. Aphids can be blasted off the plant with a hose. Their feeding activities on the tender new leaves cause them to curl. Widespread curling may be mites.

Apply an insecticidal soap to plants that have mites. Spray it on the tops and bottoms of the leaves weekly until the plant recovers. Use this formulation in the morning or late afternoon to prevent wet leaves from burning in the sun's rays.

Use a neem oil spray on all surfaces of the plant to combat any sucking or chewing insects. Such a spray has no affect on other types of insects and will not harm bees or flying bugs. It will take two or three weeks to see the insects disappear and die and then the plant will be on the way to recovery. Neem oil is safe around children and pets and on edibles.

Things You'll Need

  • Fungicide
  • Hose
  • Hose end sprayer
  • Ladder
  • Rake
  • White sheet of paper
  • Insecticidal Soap
  • Neem oil
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About the Author

Bonnie Grant began writing professionally in 1990. She has been published on various websites, specializing in garden-related instructional articles. Grant recently earned a Bachelor of Arts in business management with a hospitality focus from South Seattle Community College.