Thrips On Citrus Tree: Control Of Citrus Thrips


By: Bonnie L. Grant, Certified Urban Agriculturist

Tangy, juicy citrus fruits are an important part of many recipes and beverages. Home growers know the trees that bear these delicious fruits are often prey to diseases and many pest problems. Citrus thrips are one of the most common and are considered a threat to commercial production.

There may be other types of thrips on citrus trees, but this variety has the potential to cause the most economic damage. For this reason, control of citrus thrips is vital in areas where wide scale production of citrus fruit is common.

What are Citrus Thrips?

What are citrus thrips? They are tiny orange-yellow insects whose feeding activities scar and damage the surface of the fruit. It is important to know what citrus thrips look like, as there are other thrip pests on citrus trees, which do little damage to the fruit and require no treatment.

Citrus thrip coloring resembles the fruits upon which they dine. The body is oval and pointed with six hairy legs and fine hairs over the whole insect. They are only .6 to .88 millimeters in size and have four instars. The second instar does the most damage, as they feed on the tiny new fruits.

These insects produce up to eight generations in one year, so monitor your trees carefully and watch for citrus thrips symptoms.

Citrus Thrips Symptoms

The insects feed on the fruit buds and puncture the cells in the rind. This causes scarring and scabs. The appearance of the damage includes silvery or whitish trails, which grow larger as the fruit grows. The early scars turn into rings of damaged tissue on mature fruit.

While this does not harm flavor or texture of the pulp and juice, the marred exterior makes it appear unpalatable. This is more important in commercial production, where buyers expect perfect looking fruit.

Thrips on citrus trees can spread to commercial orchards, so management of dooryard trees is important to preserve industry production. Damage can occur to fruit from petal fall until the citrus is 1 1/2 inches (3.8 cm.) wide. The insect’s feeding also damages young leaves, which may defoliate over time.

How to Treat Citrus Thrip Pests

Control of citrus thrips must begin early in the season. For this reason, you need to be prepared and know how to treat citrus thrip pests.

Do not use broad-spectrum pesticides in your landscape, as these can kill the natural enemies of citrus thrips. Studies have also shown that populations of citrus thrips actually increase the season after spraying with such products. Try using non-chemical methods or specific formulas for thrips to avoid such population explosions.

Organically grown trees treated with Spinosad early in spring show few signs of the pests. There are also chemicals used to combat thrips, but they tend to develop resistance quickly. With eight generations each year to deal with, that adds up to a losing battle. However, some formulas of chemical control of thrips will work against pests. Pyrethroids and organophosphates have relatively non-toxic control.

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Thrips damage and symptoms – how to tell if your plant is infected by thrips

Thrips can cause different types of damage to your plants. This depends both on the plant species and the type of thrips.

Key thrips damage symptoms

Sunken streaks and patches – leaves and stems
Colored spots or patches – usually silver-white
Stunted growth – buds (flower and leaf)

Often combined with – plant virus, fungal diseases

  • How to get rid of thrips naturally
  • Learn all about thrips
  • Thrips lifecycle

Read on to discover what type of problems that result from thrips on plants. Included are images of thrips damage on fruit trees, flowers, and trees/shrubs. Damage can appear on leaves, stems, buds, fruits and flowers. You’ll get a good idea of what thrips damage looks like!


What Do Thrips Look Like?

Thrips are tiny and slender, typically only measuring about 2 mm long – super tiny! Most have two pairs of wings with fine hairs that you won’t be able to see without a microscope.

Thrips typically vary in color from pale yellow to light or dark brown, but they can be orange, black, or green as well.

Adult male thrips tend to be smaller and paler than their female counterparts. Their color can change, depending on the current temperature they get darker when the temperatures are cooler.

Female thrips lay their translucent eggs in soft plant tissue. The eggs hatch and the larval form of thrips are similar to the adults in shape, but they’re even smaller – it’s hard to believe they can be smaller than 2 mm, but they are. Larval thrips also are paler in color and don’t have wings yet.

As they grow and hit the pupal stages, they’re similar in size to the adults, but they now have wing buds forming.

As you can tell, these insects are SMALL, but they can make a fascinating study if you have young kids. You can use a hand lens or a microscope to take a closer look at the details.

Here are some interesting – and worrisome – facts:

  • Females don’t need males to reproduce – no fertilization is necessary. That means they can breed that much easier!
  • The females make a slit into the leaf tissue to lay their eggs, damaging the plant.
  • One female lays up to 50 eggs at one time, and the eggs only take one week to hatch.
  • After hatching, it only takes the thrips three weeks to reproduce and mature fully. Imagine how fast their populations can grow!


How to Kill Thrips

Last Updated: January 6, 2020 References

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Thrips are a common garden pest that feed on and infect a variety of different plants. To identify this nuisance in your garden, check the leaves, buds, flowers, and fruits of your plants for white splotches and black feces. If you’re dealing with a thrips infestation, try taking aggressive measures to kill off these pests, like installing sticky traps or using a special insecticide. To keep these unwanted visitors away, try to perform regular maintenance on your flowers and crops to keep your garden in great condition!

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Did you know? It’s not necessarily bad if you find thrips in your garden or greenhouse. There are a variety of thrips species, including a parasitic group that feeds on other thrips. Don’t worry about an infestation unless you see physical damage to your flowers and crops. [2] X Research source


Identification

Since some species of thrips actually help rather than hurt citrus trees and other garden plants, proper identification is important. Thrips are only about 1/20 of an inch long and difficult to detect. Citrus thrips range from whitish to orange in color and have short, thick abdomens. Their fringed wings are longer than their bodies but have no hairs on the tips as do some other species. Larave are white to light orange. Look for them on the leaves and fruit. Older larvae have fat abdomens. Prepupae develop small antennae that are bent backwards and they have small wing pads. The adult citrus thrip lacks the darker bands, which mark other thrip species. You may be able to see and identify citrus thrips with good light and a strong magnifying glass.


Everything a Gardener Should Know About Thrips

The exact lifecycle and how they damage plants, depends on the specific species that you are dealing with. Generally, though, they hibernate in soil through the winter. Garden soil, which is loose and easy to burrow into, is a particular favorite. In the spring, the females emerge and lay their eggs directly into the stems or leaves of plants.

Once the larvae hatch from their eggs, they are incredibly hungry. This is when they begin to feed on plant sap, sucking the nutrients directly from the plant’s leaves or stem. The thrips then go through two more growth stages before they return to the soil. Once back in the soil, they become pupae. The pupae emerge later, often after a winter spent in the soil, as winged adults.

Thrips damage plants simply by how they feed on them, scraping at the delicate surfaces of the leaves and draining them of nutrients. However, some species also help to spread diseases such as tomato spotted wilt. It has been discovered that they can actually transmit more than 20 different plant diseases and viruses.

How to Identify

Despite the vast amount of damage they’re capable of, thrips are actually quite small. Adults are only about 1/25 of an inch long. Their color will depend on the specific species you’re dealing with, but they range from light tan to darker brown or even black. They also have narrow wings.

The larvae, which are what cause damage to plants, are even smaller and more difficult to spot. They have yet to develop their wings and are often yellow or green in color.

It’s often easier to identify them by the damage they cause. Plants may have wilted or discolored leaves. This discoloration is often seen as streaks or patches. In addition, some thrips cause rolls or folds in the leaves.

Prevention

Aside from the solutions listed above, you can also work to make your garden a less appealing place for thrips in general. To begin with, they are often attracted to bright colors, particularly yellow, white, and blue. Using a sticky trap in these colors can confuse them and may help you trap them. This can often mean trapping females before they have a chance to lay their eggs.

Aside from ladybugs, there are also a number of other beneficial insects, such as pirate bugs, that eat thrips. Making your garden an appealing place for these insects can help to control problems with thrips. It can also help to ensure that the ladybugs you’ve introduced stick around. For example, ladybugs thrive when plants such as tansy, geraniums, cilantro, and cosmos are present.

When introducing new plants to the garden, it’s important to carefully inspect them for any signs of thrip damage. Plants that you worry may be infested should either be quarantined or disposed so that you do not introduce the pests into the rest of the garden.

Tips for Applying Insecticides

Insecticides such as neem oil, insecticidal soap, and Spinosad are generally considered safe for plants. However, it’s always important to test how your plants will react to a product before applying it more broadly. This is particularly true for insecticidal soap, which can sometimes be too harsh for plants. You can test any solution by spraying a few leaves or a small part of the plant and observing the plant for a day or two. If the plant reacts poorly, stop using the insecticide. The good thing about gentle solutions such as insecticidal soap and neem oil is that it does not harm beneficial insects such as ladybugs.

Even organic products can sometimes be harmful to the environment. In order to mitigate the risk of harming the ecosystem, try to eliminate runoff. Only use sprays on dry days when there will be no rain for at least 24 hours. In addition, try to only spray on still days when there isn’t too much of a breeze.

In order to keep honey bees safe, don’t use any harsh chemicals when flowering plants are in bloom, which is when bees will be visiting most frequently. Creating a garden that’s safe for bees means creating a garden that’s healthy and thriving.

Bottom Line

Again, I recommend buying live ladybugs for your thrip problem. Don’t make the mistake of buying any average insecticide at your local gardening store only to find it is not effective weeks later. Many of them will simply not produce the same results. You cannot go wrong with any of the insecticides above.

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About the author: Carley Miller is a horticultural expert at TheGreenPinky. She previously owned a landscaping business for 25 years and worked at a local garden center for 10 years.


Watch the video: Monitoring for Thrips in Avocado Orchards


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