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Unlocking the Citrus Spray Secrets: When and Why to Spray Your Citrus Trees

Updated: Dec 19, 2023

What Is Citrus Spraying?

The Golden State is a giant in the production of citrus, but our best days may be behind us if we can’t defend against the threat of sucking insects.

Trouble in the Golden State

The late afternoon sun sets behind you as you lumber towards your front door after a long work week. Yet, something about your front yard feels off.

Hmm, maybe you’re just tired.

Tomorrow’s Saturday, and you plan to have your morning coffee in your garden. The lawn chair next to the lemon tree will do.

Lemon Tree

You step outside with your cup of Joe and think, “Joe, always trust your gut!”

There’s a distorted new growth on your beautiful tree, and the leaves are sticky. Sooty even! Can trees even get mold? You thought that was just for your forgotten lunch in the breakroom.

What do you do?

Well, the internet told you to call up an ISA Certified Arborist at Sims Tree Health Specialists, Inc., to diagnose your sick tree. So, you did.

“Diagnosis, Doctor?”

It’s not pretty, but there’s hope. Your lemon tree has sucking insects: Scale, Aphids, Whitefly, and the Asian Citrus Psyllid. (Stay with me; It’s a theoretical tree. It has everything). Citrus Spraying is recommended to combat these ailments.

What Is Citrus Spraying?

According to our ISA Certified Arborists, citrus spraying is a treatment recommended by your county Agricultural Department and U.C. Riverside to reduce the spread of greenings disease, or huanglongbing (HLB).

Citrus Spraying is the most effective in combating sucking insects when the treatments are done on a scheduled basis throughout the year.

Depending on the severity of the infestation, citrus spraying typically can be performed every three to six months. Like medicine, it’s best to keep up with services to fight off the insects.

Your fruit won’t just be for decoration! Before eating, wash the fruit with some dish soap and water.

What’s Included in Citrus Spraying?

Our ISA Certified Arborists typically recommend an insecticide spray to combat Scale, Aphids, and Whitefly. If the infestation is particularly heavy, they may recommend a pesticide (don’t worry, it won’t absorb into the fruit). Fertilizer is encouraged as well!

Defined by our ISA Board Certified Master Arborist, Susan Sims, a Scale infestation tends to “make the plant unthrifty.” The tree is robbed of its resources to grow and produce fruit.

There is another sucking pest, the Asian Citrus Psyllid, that will also require insecticide spray to combat its disease.

What Is the Asian Citrus Psyllid?

The Asian Citrus Psyllid is a sucking insect that feeds on the juices of the tree leaves and is a carrier of huanglongbing or HLB. When it gets hungry, like all living things, it feasts on citrus trees, spreading the bacteria as it goes. Found on various citrus varieties, the Asian Citrus Psyllid is spreading the Citrus Greening Disease and threatening California’s Citrus Legacy.

Asian Citrus Psyllid

Citrus Greening Disease may be present on your citrus trees if you’ve found: shoot and leaf yellowing, fruit asymmetry and the slowing of fruit growth, and trees dying prematurely.

Citrus Spraying vs. Biological Control

If a tree is stressed, it releases pheromones that attract pests and weaken the root system.

Like how a doctor may suggest a diet change and exercise after a health scare, biological control helps make the plant overall healthy, giving it its own general immunity.

However, biological control does not control pests.

By preventing undue stress, biological control techniques like effective watering and the addition of beneficial biologicals (hey, ladybugs!) will help give your tree the strength it needs.

But sometimes a healthy diet isn’t enough.

Citrus Spraying is the most effective manner to control pests.

Just like you can’t take only one painkiller and think you’ve gotten over the flu, a tree will need multiple citrus spray treatments to “get over” a case of sucking insects.

Organic treatments are available, but their effectiveness is less intense than conventional citrus spraying with insecticides and pesticides. According to the California Statewide Integrated Pest Management Program, organic insecticides require more frequent application on a tree as the product must contact an insect’s body to be effective. Organic treatments may last only a few days, whereas conventional treatments may last several months!

TLDR – What’s The Point?

Citrus Spraying is the most effective means of eradicating sucking insects attacking your citrus trees. Citrus spraying = less treatments + happier trees + more money in your pocket.

Orange Tree

About Sims Tree Health Specialists, Inc.

Sims Tree Health Specialists, Inc. dedicates itself to preserving, educating, and improving the health of trees and ensuring their safety. Sims THS has provided California’s Urban Forests with premium healthcare since 1972. To learn more, visit our website:

Sims THS offers services with our ISA Certified Arborists in the following:

Diagnosis and Disease Management, Pest Suppression, Organic Solutions, Fruit Suppression, Drought Protection, and Arborist Assessment Reports and Preservation Plans.

In addition to providing quality tree health services, the Sims family is known for their educational pursuits. In 1996, they started the Sims Tree Learning Center (TLC), a 6-acre botanical garden and research facility sponsored by Sims Tree Health Specialists, Inc. The facility houses multiple types of gardens, including a cactus and succulent garden and one of the largest collections of Palms in the Inland Empire. Learn with us!


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