Experienced growers of stone fruits and citrus will be well acquainted with the pests that tend to affect their crops and effective strategies for protecting the harvest. However, for novice orchardists and conventional growers who are looking for new techniques and bee-friendly measures, this quick-reference list of citrus pests and environmentally-integrated management strategies should help you get off to a fabulous start.
Getting to Know the Insects in our Ecosystem
As professionals who work with nature, we are acutely aware that we form part of larger systems — systems such as climate that ensure the correct rainfall, temperatures, and wind patterns for the crops we grow, all the way down to the microscopic bacteria that work to keep the soil aerated. Citrus pests — much to our dismay — happen to form part of the animal kingdom along with beneficial critters like bees, ladybirds, and hummingbirds.
As you would know from experience, it’s impossible to affect one part of the animal kingdom without affecting another. However, in the best-case scenario, we can often find ways to keep out the insects and bugs we don’t want while protecting — and even encouraging — the presence of beneficial insects and birds.
Integrated Pest Management
The best and most balanced method of dealing with citrus pests is summed up in the Integrated Pest Management (IPM) philosophy. This approach to controlling fruit pests begins by optimizing the natural balance of pests and the predators that eat them, adding chemical controls only as needed, only when most effective, and using the safest chemical possible to do the job.
Creating a Healthy Orchard
Before even considering chemicals, it’s important to make sure that your trees are vigorous and healthy, that the areas around the trees are free from weeds and debris, and that fruit trees are pruned regularly to promote good airflow and sunlight.
Beneficial Bugs to Look For
Once you’ve done your part in creating an orchard that’s robust and well aerated, begin to look for the beneficial bugs that serve as your first line of defense against citrus pests:
- Leatherwing beetles
- Ladybird beetles
- Ground beetles
- Praying mantis
- Pirate bugs
- Parasitic wasps
Any chemicals that you do decide to use should be as safe as possible for these hard-working critters, as damaging your predator population could lead to an exponential increase in fruit pests.
Common Citrus Pests and Management Solutions
Now, let’s take a look at 13 of the most common fruit pests, the crops they affect, and how to handle them if they appear on your plants.
Citrus Pests in the Dormant Season
- San Jose Scale
This is a small, yellow insect that climbs on fruit and kills the shoots of several kinds of deciduous fruit and nut trees. Natural controls include limiting tree size, encouraging parasitic wasps and lady beetles by avoiding summer sprays, and applying oil sprays in the dormant season as outlined here.
- Leaf Curling Aphids
This category covers several kinds of aphids that attack apple, plum, and cherry trees — among others — and cause the fruit and leaves to become stunted. For these citrus pests, you are looking at soap-and-water solutions and agricultural sprays rather than cultural controls, as aphids develop much faster than their predators. At a minimum, grow vegetable seedlings under covers and apply reflective mulch to scare them away.
- Pear Psylla
This small, cicada-like pest attacks pears and causes pear decline, leaf burn, leaf curl, and honeydew with sooty mold. Their natural controls are predators and parasites, so it’s essential to avoid spraying in the summertime. If you see evidence of this pest on your plants, spray with oils as indicated here.
- Blister or Rust Mites
These tiny mites can only be seen through a hand lens and cause significant damage to pears and nectarines. To control this pest, encourage the development of predaceous mites by avoiding chemical sprays over summer and apply these sprays only if and when needed.
- Peachtree Borer (PTB)
Peachtree borers (PTBs) are seen as mature, chocolate-brown larvae that kill new shoots and feed on the surface of fruit. These very small fruit pests affect prune, plum, almond, apricot, peach, and nectarine trees. The best form of management for PTBs is to follow the spraying schedule described here.
Citrus Pests from Petal Fall to Harvest
- Codling Moth
The codling moth is one of the most well-known pests in apple and pear orchards and invades the growing fruit at the worm stage of its life cycle. While this pest is difficult to control using natural measures, cultural measures like sanitation, bagging fruit, and using temperature gauges and pheromone traps can help. Beyond these strategies, agricultural sprays provide the main method of managing or eradicating this pest.
Orchard Pests in Summer
This kind of mite has the appearance of a tiny spider and requires a hand lens to see. When present in large enough numbers, these citrus pests damage the leaves, blossoms, and fruit of several kinds of fruit and nut trees. The best way to prevent these pests is to avoid chemical sprays so that populations of natural enemies can build up. Agricultural sprays provide a second line of defense against mites.
This second in our list of aphid citrus pests feeds on foliage and distorts the shoots in several kinds of fruit trees. This kind of aphid has a wooly appearance and is covered in a white-colored, cotton-like wax. Fortunately, several kinds of natural predators feed on these fruit pests, including parasitic wasps, damsel bugs, syrphid fly, minute pirate bug, and green lacewing — so be sure to avoid chemical products that could damage these predator populations before the summer. Agricultural sprays for this pest can be viewed here.
- Redhumped Caterpillar
This yellow caterpillar with black stripes, a red hump, and a red head tends to go for deciduous trees like walnut, plum, and prune. With its voracious appetite, it can strip all of the foliage on a branch quite quickly, putting young trees at particular risk. If you have the time, pick these citrus pests off the leaves manually and remove clusters as you see them. A list of effective sprays can be found here.
Orchard Pests from Green Tip to Petal Fall
- Fruit Worms
The heading of “fruit worms” really describes a group of citrus pests that includes the fruittree leafroller, the obliquebanded leafroller, and the green fruitworm. While fruittree leafrollers and obliquebanded leafrollers feed primarily on citrus, almond, stone fruit, apple, and pear trees, green fruit worms prefer apples, pears, prunes, plums, cherries, and apricots. When the larvae are still small, these worms have a few natural predators, and birds tend to hunt them later on. Specific sprays can be used if needed for the green fruitworm, fruittree leafroller, and obliquebanded leafroller, respectively.
Thrips represent another group of fruit pests that damage apples, pears, and stone fruit, among others. This category includes flower thrips, pear thrips, and madrone thrips. Fortunately, there are a few natural strategies that help to reduce thrip populations — including sanitation, the removal of host plants, encouraging parasites, and avoiding placing areas of weeds or grassland near the orchard that might become wet and dry up again afterward. Information about sprays for thrips can be found here.
- Plant Bugs
This category of citrus pests includes consperse stink bugs, conchuela stink bugs, redshouldered stink bugs, lygus bugs, false chinches, and leaf-footed boxelders. These plant bugs tend to attack pear, apple, stone fruit, and other plants, leading to fruit that is dimpled and pithy. The first line of defense against plant bugs is taking natural measures, such as sanitation, weeding, removing host plants, and encouraging parasites. Spray information for each of these bugs can be found below:
- Consperse stink bug
- Consperse, conchuela and redshouldered stink bugs on apple trees
- Lygus bug
- False chinch bug
- Boxelder bugs
- Pacific Flatheaded Borer
The final bug on our list of citrus pests is the Pacific Flatheaded Borer (PFB). At the larva stage, the PFB gets into the wood and mines and girdles the limbs and trunks of deciduous fruit and nut trees. To reduce the damage from the PFB, you can whitewash the trunks of trees to help prevent sunburn, and prune the trees so that the larger branches are shaded. Sprays that you can use with this bug are described here.
Fruit Growers Supply — Niche Solutions for Fruit Growers
Whether you’re currently dealing with an infestation of citrus pests or wish to prevent a potential outbreak, Fruit Growers Supply Company has all of the tools and solutions that you need to avoid widespread damage to your crops. Our extensive range of products for agriculture covers organic production as well as conventional. Drop by or call one of our full-service stores in Orange Cove, Woodlake, Riverside, Porterville, or Santa Paula to find effective equipment for fruit pests in your orchard.