Protecting Your Citrus Tree from Pests

Pests act on citrus plants in different ways. While some pests attacks the fruits, others will drain the life out of the tree itself, causing collar rot, damaged foliage and decreases the yield of fruits. It is important to learn to identify common garden pests that attack citrus trees so that you can take early steps to cure them and ultimately to prevent them from happening again. Some of the more common pests, like snails, aphids, fungus, and spider mites attach citrus plants. Below outlines some steps you can take to prevent and protect your citrus tree from being attacked by pests.

A Clean Living Area

Like humans, plants also require a good hygienic area to live on. Most pests are attracted to a plant because there are opportunities for them to live on, such as a litter of dead leaves and debris collecting at the base of the tree. Snails welcome this and will chew on leaves and fruits, causing quite substantial damage if not tackled early. Keep the area around the base of the trunk clean, and prune branches that are hanging too low so that they do not reach the ground. Install a set of protectors at the base of the trunk to prevent snails from climbing up the tree.

Prevention is better Than Cure

Sometime pre-empting pests before they actually attack your plants will save you a whole lot of headache later. For example, aphids are some of the most destructive insects found in temperate countries and attack citrus fruit trees, garden plants and houseplants alike. Also known as plant lice, aphids can inflict decreased growth rates, mottled leaves, yellowing, stunted growth, curled leaves, browning, wilting, low yields and death in plants.

The spread of aphids can be prevented or reduced by spraying your citrus fruit trees with an insecticidal soap. This step will prevent any severe infestation of aphids which may require huge doses of insecticides to control later.

Using Pesticides

Most pesticides that are used come with specific instructions on how to apply them to the field, and some are poisonous. Use pesticides with caution, as they can be detrimental especially when you use them on fruit trees like citrus. You should not use them when the trees are flowering, and make note of which season when exactly when you should apply them.

There are other alternatives to chemical pest control, including methods of cultivation, the use of Biological controls such as pheromones and microbial pesticides, genetic engineering (which of course is a method we won\’t use if you\’re just a home gardener), interfering with insect-pest breeding, and releasing other organisms that are natural predators or parasites of the pests.

Whatever method it is that you choose to use, make sure that you know exactly what the consequences are when using pesticides in your garden. Ensure that you understand the directions on how to apply them to the plant, and always practice safety measures like wearing a mask, safety goggles and gloves when handling chemical pesticides.

Keeping an Eye on Your Citrus Fruit Tree

Also check on your tree periodically. Observe if there are any damages or abnormal symptoms on the leaves, bark or fruits. Make note of the amount of foliage that dropsm or any color changes or curling leaves.

Also be aware of any infestation of insects that may not damage your plant, but signify the presence of other insects that can. For example, the presence of ants on your tree (who may not damage the tree) is an indication that there is honeydew drawing them there, which is likely excreted by sap-sucking insects. These insects in return are the damaging agent for your tree.

Knowing Thy Enemy

If you can spot problem symptoms on your tree early on, you will need to be able to \’diagnose\’ the problem and take steps to rectify and prevent future occurrence. You will need to know how to identify these symptoms and the type of pest control product that you can use.

The table below shows common citrus pest problems, when they normally occur and when the first symptoms appear, as well as how to control them

SymptomTime periodPrimary causeOccursControl/comments
Premature rind coloringLate SummerPlant bugsMid-summerRarely serious enough to control
Rust colored or brown rindAnytimeCitrus rust miteSince bloomDoes not effect eating quality; use miticide only if necessary
On fruit: Small, brown spots on rind, with rough texture, may tearstreak / on leaf: Small, brown spots, sand-papery textureHarvest/Spring-summerMelanose fungusMarch-April / after growth flushAffects grapefruits only, remove dead twigs inside canopy
Removable, small, colored, raised spots on rindsummer to harvestscale insectsSummerSpray only if problem is extensive on the bark
Cottony masses near fruit stemsummer to harvestmealybug or cottony cushion scaleSummerRarely serious, hard to control
Black, sooty covering on fruits and leavesharvest / anytime on leavesSooty moldSince bloomWhiteflies, blackflies, mealybugs and other insects, usually gone before problem is noticed; wash off with soapy water
Leaf cupping and curlingafter new flushAphidsDuring each flushTake preventive measures
Silvery, scratchy appearance to leafsummer, fallspider mitesspring to fallCould cause excessive fall leaf drop, spray if necessary
Irregular, oily spots on foliagesummer to wintergreasy spot fungusSummerRemove fallen leaves, particularly in summer
Removable, small, colored spots on leaves or barkAnytimeScale insectsSummerSpray only if infestation is extensive
Fish-scale-like scales underleaf, translucent; small, white, flying insectsspring to fallWhitefliesspring to fallLeads to sooty mold; rarely requires control
Spirals of eggs or small black insects underleafAnytimeBlackfliesanytimeLeads to sooty mold; insecticides do not work, parasites normally in control

More reading: Trees: Citrus Insects and Diseases:

How to Manage Citrus Trees

Food and Agriculture Organization of the United Nations (2002), International Code of Conduct on the Distribution and Use of Pesticides


Soil Steam Sterilization method: