Ways to control thrips pests on indoor plants

Author: Elena N. https://floristics.info/ru/index.php?option=com_contact&view=contact&id=19 Category: Plant Pests Published: November 07, 2017Last edits: October 26, 2020

Measures to combat thrips in the garden

Fighting thrips on cucumbers

Thrips on onions

Thrips on gladioli

Thrips on roses

Remedies for thrips (preparations)

Fighting thrips with folk remedies

Types of thrips

Literature

useful links

Comments

Thrips (lat. Thysanoptera), or vesicopods (fringed-winged, club-footed) are a group of small-sized insects common on all continents. Thrips were first described in 1744 by Karl de Geer, and today more than 6,000 species of these insects have been identified, grouped into more than a hundred genera.

How to fight thrips on houseplants

Thrips on indoor plants: how to fight them in this protracted war? Agree, you don’t always win the battle with a pest. Thrips, unpleasant and dangerous insects, have many species that differ significantly from each other not only in size, but also in color. They attack the plant mainly with their numbers, because each individual reproduces every 6 days, doubling the colony. Therefore, the fight against them is difficult and lengthy. It seems that all the thrips have been destroyed, but after a couple of weeks they again draw all the juices out of the plant. The flower weakens and withers right before our eyes.

Main types

Thrips on roses - how to get rid of parasites

Due to the fact that the size of the insect is very small, it is difficult to immediately determine the type of thrips. Scientists distinguish up to 2000 varieties. 300 of them are found in the Russian Federation and neighboring countries. The list of the most common is as follows:

• heterogeneous;
• decorative;
• dracaena;
• bulbous
• tobacco;
• rose;
• California thrips.

By their name you can determine which plants they like to attack. Decorative can live both in the middle zone and in more northern regions. It can harm the Phalaenopsis orchid and other species of this plant, as well as the monstera palm and dieffenbachia. Less than 2 mm in size, brown in color.

Tobacco thrips

Not all thrips are equally dangerous to plants, but there are hundreds of them that should be destroyed immediately. The pest consumes the juices of leaves and fruits, and also transmits diseases and leaves toxic secretions on the flora. Thrips lives secretly, hiding in secluded places. Therefore, it is not always possible to detect it in a timely manner at the very beginning.

What do thrips look like?

The most numerous insect pest species is thrips. Their size ranges from 0.5 mm to 5 mm. The color can also range from transparent milky individuals to black. The body is oblong, has two wings with a fringe characteristic of these insects located along the edge of the wing.

Indoor thrips species have a size of 1-1.5 mm. The appearance of insects can vary significantly even within the same species.

thrips varieties

The laid larvae are similar in appearance to the adults, but their color is usually translucent white or light yellow. They do not have wings, unlike adult insects. The most common and well-known types:

1. Frankliniella intonsa is a multivorous thrips that damages the developing ovaries and flowers of the plant.
2. Hercinothrips femoralis is an ornamental thrips that likes to settle on large plants such as amaryllis, chrysanthemums, callas, cacti and gardenias.
3. Parthnothrips dracaenoe - dracaena thrips, spoils aralia, tradescantia, dracaena, hibiscus; Thrips fuscipennis - This thrips prefers forbs.
4. Thrips tabaci - tobacco thrips; its name makes its preferences clear.
5. Liothrips vaneeckei is an onion thrip that loves to eat gladioli bulbs.

Insects feed on the sap of the plants on which they settle. The paths that they gnaw in the tissues of leaves eventually become visible to the naked eye. In room conditions, the number of individuals doubles every 6 days.

Thrips pest - description

The length of the black, brown or gray body of thrips reaches from 0.5 to 3 mm, some species are much larger - about 14 mm. The legs of thrips are running, the mouthparts are asymmetrical, piercing-sucking, and the paws are without claws, but are equipped with teeth and a bubble-like suction device. The abdomen of thrips consists of 11 segments. There is fringe along the edges of the wings. Thrips develop through five stages: eggs, larvae, pronymphs, nymphs and adults. Thrips larvae have a grayish or white-yellow body, otherwise they differ from adults only in the absence of wings.

Thrips are polyphages, that is, omnivorous insects. They are one of the most common pests of agricultural, vegetable, fruit, ornamental and indoor crops. They pose a particular danger to plants indoors: if thrips are infested in greenhouses, it is very difficult to get rid of them; you can only contain their population numbers. It is difficult to detect these pests due to their small size and secretive lifestyle: they can parasitize one plant for a long time without spreading to neighboring ones.

Adults and larvae suck the sap from the above-ground parts of the plant and infect them with their secretions. First, discolored or yellowish spots, streaks or stripes appear at the bite sites, which gradually merge. As a result of the activity of pests, plant tissue dies, holes form in place of the spots, leaves wither and fall off, flowers lose their decorative effect and fall off prematurely. When a plant is massively occupied by thrips, silvery areas appear on its ground organs, the stems are bent, and the flowers are deformed due to the fact that the pests have damaged the flower buds. On top of that, thrips are carriers of incurable viral diseases.

• Why do the leaves of flowers turn yellow?

Thrips on indoor flowers

Thrips love “thoroughbred” plants. Flowers such as:

• rose;
• dracaena;
• ficus;
• laurel;
• monstera;
• lemon;
• palm.

Although the insect can feed on any indoor plant. When infected with these harmful insects, the leaves of the plant begin to lighten. Numerous punctures appear from the thrips' voracious trunk.

plant leaf affected by thrips

At the same time, brown spots appear on the inside of the leaf. When insects attack a plant, they destroy the leaves and begin to die. Flower buds become deformed and inflorescences take on ugly shapes.

Criminal traces! If you carefully examine an indoor flower, you will see pollen spilling out from the stamens of the flowers on the leaves. This is a clear sign that a colony of thrips has settled on the plant. Although this can happen when the flower is shaken or infected by one of the types of mites.

To recognize the cause of pollen shedding and make sure that thrips are present or absent, pick a flower. Tap it lightly with a pencil or ballpoint pen on a dark-colored sheet of paper. This method will show whether the plant is infested with pests.

You can also experimentally determine what type of “beast” has settled on your pet. Perhaps a greenhouse or ornamental thrips has settled on the flower. Symptoms of thrips and flat mite infestations are very similar. But please note that thrips are harsher than ticks.

Over time, these pests will turn your gorgeous pet into an obvious ragamuffin with terrible “scars” on the leaves and barely alive flowers that are in the last stage of exhaustion. Petals speckled with dark and light spots, half-withered and deformed flowers evoke pity, not delight, when looking at them.

There are also types of thrips that have only one generation per year; these are usually local species brought into the home by the wind, or with flowers from the garden plot. Such species are peaceful in nature and will disappear from the “battlefield” by autumn.

You should be afraid of the appearance of California thrips on house flowers, a very harmful eater of indoor specimens.

How to recognize parasite damage

The thrips themselves are not always immediately detectable. They are quite secretive and prefer to manage individual plants, gradually moving to others.

Discoloration of some leaves should raise suspicion among the grower. Also, in flowering plants, pollen intensively spills from the stamens onto the petals (the same phenomenon can be observed during hot weather and as a result of a spider mite attack).

If, upon examination, many small punctures are recorded (like from a needle on fabric), it means that they were made by thrips, which means they drank juice from the plant.

Brownish or brown spots can be seen on the lower part of the leaf blades. These are damaged areas. When oxygen enters plant cells, they often take on a silver color. You can also notice a sticky mark and brown-black dots (thrips feces) on the leaf, which contribute to the development of a disease such as sooty fungus.

A late sign of a thrips attack (if rescue measures have not been taken) is the falling of leaves and flowers, as well as bending of the trunk.

Where do thrips come from?

Forewarned is forearmed! In the summer, flower pests easily penetrate into a person’s home with gusts of wind, with soil brought from the garden plot. When buying new varieties of house plants, you also run the risk of introducing pests into your home; there is no insurance against infection spread by thrips.

With onions brought from the dacha, California thrips gets into the house. Summer, a time of intensive exchange between gardeners with rare house plants, then? there is a danger of infection. At this time, flowers are often moved to balconies and loggias protected from the wind, but with drafts, when ventilated there is still a risk of catching thrips.

California thrips

Summer, heat and dry air are favorable conditions for the spread of this evil pest. He loves high summer temperatures. As the weather gets colder, the intensity of thrips distribution drops significantly.

Use of hazard class III insecticides

Chemicals are dangerous to humans, so it is recommended to use a respirator, goggles and gloves when treating plants with them. Spraying or watering is carried out in the morning, then leave the room and ventilate it for 3-4 hours. If it is impossible to leave the room, the treated flower is placed in a plastic bag with a zipper. For 3–4 days after applying the insecticide, you should not sleep in the same room with sprayed flowers.

As a rule, all drugs used to exterminate the Colorado potato beetle help against thrips. When exterminating pests, an integrated approach is important:

• plants are sprayed with contact and systemic insecticides at least 3 times, the interval between sprayings is a week. Repeated applications are necessary because most class III insecticides do not affect eggs;
• 3-4 days after spraying, the soil in the pot is spilled with an insecticide solution: this is necessary to destroy the thrips larvae. The insecticide is used only during scheduled watering. To treat the soil, insecticides are used in the form of powder or granules. Preparations in the form of an emulsion concentrate contain organic solvents that are harmful to the root system;
• insecticides reduce plant immunity. After destroying thrips, it is recommended to treat indoor flowers with anti-stress preparations “Epin” or “Zircon”.

Store-bought anti-thrips products:

• "Fitoverm" is an insectoacaricide that is least toxic to humans. The drug does not inhibit the growth of indoor flowers. The active ingredient is aversectin. Dosage – 2 ml of product per 200 ml of water;
• "Bankol" is a Japanese insecticide, a synthetic analogue of annelid worm secretions. The product has low toxicity to humans and decomposes very quickly. The active ingredient is bensultap. Dosage – 0.5 g per 1 liter of water;
• "Apache" is a Japanese insecticide, the active ingredient is clothianidin. Dosage – 0.5 g per 1 liter of water;
• "Aktara" is a systemic insecticide with enteric contact action, the active component is thiamethoxam. Dosage – 1 g per 1.25 liters of water.

Thrips control

Whatever plants become infected with thrips, preventive measures should be taken. Strictly monitor air humidity, pests cannot tolerate moisture. In the summer, give your green pets a shower, with soap foam, preferably from baby soap. This is an almost 100% guarantee against this malicious pest.

Be sure to conduct a visual inspection of your indoor garden once a week. You will admire your flowers and at the same time inspect them for infestation, both pests and any infection.

Stock up on adhesive tapes to place them among the leaves of plants; this is also a preventive measure in pest control. Everyone recommends using your own ribbon color; some say that thrips are best caught on pink, while others recommend blue.

Who claims that only the yellow color of the trap is suitable for catching pests? Thrips have wings, which means they can easily migrate from plant to plant. This is the reason for the rapid infection of green pets in the same room.

A fight for life and death! Thrips are persistent individuals and are extremely difficult to fight, mainly because they lay eggs inside the leaf. Since they are protected by fibers, they are practically indestructible; neither pesticides nor any other means take them.

thrips larva

Thrips love dry, hot air; at a temperature of +20-25˚C they double their numbers every 4-5 days. Just imagine what hordes of greedy and hungry pests these are. If you don't fight them, they will destroy everything that blooms and grows in the house.

If you find thrips on at least one plant, inspect the nearby flowers and give all your pets an urgent wash with soapy foam. This is prevention. Be sure to place the infected plant in quarantine, let it stand in a room separate from other seedlings, and you will observe it at this time.

The place where the infected pet stood? The top layer of soil in the pot should be removed and the substrate needs to be replaced. It should also be sprayed with insecticides. Before cultivating the soil, the plant should be given a shower; this will not harm it.

Note! Treatment with a soap solution is not a panacea; it is better to treat the plant with chemicals. Thrips are very difficult to destroy, so chemistry is better than the soap solution often used by gardeners.

Signs of a pest presence

On plants favored by pests, even if the pests themselves are not visible, the following symptoms can be noticed:

1. Yellow-gray streaks appear on the upper side of the leaves.
2. On the reverse side there are rounded brown spots.
3. The edges of the leaf blades appear damaged, with brown spots.
4. The buds become smaller or do not set.
5. The leaves, trunk, peduncles are covered with a sticky coating.

Signs of presence

Remedies for thrips

In war, all means are good! Products used for spraying plants often require additional actions, such as covering the flower with a plastic bag for a day. So, get to know these drugs:

1. Vertimek - dilute 2.5 ml of the drug in 200 ml of water, spray the infected flower with this solution and cover with a bag.
2. Fitoverm - dissolve 2 ml of the drug in 200 ml of water, and spray the plant, covering it with a transparent bag for a day.
3. Aktelik - dilute 1 ampoule in 1 liter of water, the solution has a very pungent odor, it is better to process it in the fresh air. Spray the plant and cover with a bag.
4. Agravertine - take 5 ml of the drug for half a liter and dilute it in warm water not lower than +18˚C; at low temperatures it does not saturate plant tissues well. Treat the flower with the prepared solution and again cover it with a bag for a day.
5. Confidor - the soil of an infected flower is treated with a solution.
6. Kabofos is a proven remedy for pest control; it is also used on the plant substrate.
7. Intavir - dilute 1 tablet per 10 liters of water, spray the plant with it, cover with a plastic bag.

After 24 hours, remove the covering bags from plants treated with one of the listed preparations. Spraying should be done every ten days of the month until the pests are completely destroyed.

Biological drugs

The use of biological preparations is not only effective in the fight against thrips, but also safe for humans. The best, according to many gardeners, is Fitoverm, which is diluted with 10 ml per 1 liter of water. It is necessary to spray with Fitoverm every three weeks to destroy the larvae hatching from the eggs. Another excellent universal drug “Aktar”, which is prepared at the rate of 1 sachet per 4 g, diluted in 5 liters of water. Treatment is carried out once a month.

How to deal with pests at home

On the forums they talk about how to combat flower pests at home:

1. Collage advises: spray the plant with condifor, and writes that he is amazed at the result. After treating the flower with the solution, by evening the thrips fell off dead and he never saw them on the plant again. The solution was prepared in the following proportion: 1 gram of the drug per half-liter jar of water.
2. Kroki: got rid of thrips using the drug phytovert. A one-time treatment was enough, but to calm your conscience, you can do one more. Some time after the destruction of the “conquerors”, the plant should be supported with epin.
3. Natali advises: if signs of a plant becoming infected with thrips appear, cut off all flower ovaries. They are still deformed; pests will “help” them with this. It's difficult to fight them. The plant must be treated several times, possibly several times when the larvae emerge into the “light.” Therefore, about 5 treatments are carried out to destroy the entire thrips colony. You cannot leave even one pest alive.

Methods of disposal in an apartment

The appearance of these pests frightens gardeners, but they can be dealt with if you know what methods to use to combat the problem. Fighting methods can be varied.

Some radical chemicals include:

• Agravertine is an insecticide, 10 ml of which should be mixed in a liter of water and sprayed on the flower. After this procedure, the plant needs to be covered with a bag for a day. After this, the leaves should be washed under a warm shower;
• Fitoverm is an effective insecticide; the nature of its effect and rules of application are similar to Agravertin;
• Spintor is an insecticide based on natural ingredients. It has a soft effect. To apply, it is necessary to spray the trunks and leaves with a 0.05% solution four times with a seven-day gap between spraying;
• Neurotoxins: Apache, Dantop, Mospinal. It is recommended to use every day in strict accordance with the instructions;
• Chemicals Bi-58, Marshall and Aktellik are fast-acting, but also dangerous. It is recommended to use them with extreme caution. If used carelessly, the drugs can cause allergies or burns.

First of all, before starting treatment, it is recommended to separate the damaged plant from others in order to minimize the likelihood of infection. In addition, it is worth thoroughly disinfecting the surface on which the flower was previously located. Regular household disinfectants are suitable for this.

How to destroy a pest

Strategic offensive plan! In the initial stage of flower infection, it is possible to fight the pest by spraying it with infusion of tobacco, hot pepper, and soap solution. But these are weak “medicines” against thrips; they can rather be called preventive than curative.

This pest is persistent and it is very difficult to get rid of it with weak infusions. Better use insecticides. In the fight against thrips, natural remedies recede; only chemistry can cope.

At what temperature do thrips die?

The optimal temperature for the development and life of thrips ranges from +15 to +30˚С. At the egg stage, too high a temperature is not required, since it tends to dry out and then die, +20-25 degrees, the best conditions for eggs.

Then comes the time of the larvae, at +27˚C it begins to molt. Five days is enough for her to reach the size of an adult; after molting, she turns into a protonymph.

thrips nymph

High temperature +27˚С promotes rapid (within 24 hours) transformation into a nymph. After three days she is already an imago, and a day later the mature thrips will make its first flight.

An individual lives for a month or a month and a half, the lowest temperature of the pest’s existence is +9.5˚C. Below the temperature is not acceptable for this aggressor; at zero or below the thermometer mark, death awaits him. It overwinters in the soil in the adult stage.

Prevention

To avoid having to spend money and time fighting very tenacious insects, preventive measures will help. Keep your green garden clean. Water the plants regularly, but do not create a “swamp”. Inspect the soil periodically. Check the trunk, flowers and leaf mass. At the first suspicion of an infestation, try to find out exactly the type of pest and begin fighting them.

Very often, thrips enters an apartment with presented bouquets. Try to keep them separate from indoor plants. If possible, take it out onto the balcony and carefully examine the bouquet you brought. Even if all preventive measures are carefully observed, there is no complete guarantee that plants will not be attacked by thrips. If this problem occurs, take every precaution to ensure your houseplant remains healthy.

"Fitoverm"

The product will need to be diluted in two hundred milliliters of warm water. For one treatment, two milliliters of the drug is enough.

The liquid should be sprayed onto the affected areas. For better concentration, it is necessary to cover the plant with a transparent polyethylene film. The protection can be removed after 24 hours.

"Vertimek"

To make the solution, you need to mix two and a half milliliters of the product in ten liters of water. The drug can be used in all crop zones. To enhance the effect, you need to use a protective cover.

"Agravertine"

Less effective drug. Reducing the thermometer mark below + 18 degrees reduces the concentration of the product. For half a liter of water you will need five milliliters of natural insectoacaricide. It is recommended to use a plastic bag during the day.

"Aktelik"

It has a strong unpleasant odor. Not recommended for use indoors with insufficient air circulation. For processing, you will need to dissolve the ampoule in one liter of water. Polyethylene facilitates the penetration of the drug into plant tissue.

Pheromone traps are also used to successfully combat thrips.

Here's how they work: a capsule containing a synthesized sex pheromone is placed in a trap with a sticky bottom. The attractant attracts male thrips, they fly into the trap and stick. Pheromone traps make it possible to constantly monitor the number of pests and, acting as an indicator, make it possible to predict the damage caused by the pest, which helps to apply insecticides most effectively.

Using sticky traps against thirps

One of the simplest, most convenient and at the same time quite objective methods for monitoring phytophages is the use of yellow glue traps. They are used to monitor both thrips and whiteflies, as well as leaf miners and aphids. Traps are placed 30 cm above the crop, the norm is 50 pieces/ha. It is effective to place diagnostic traps in places where pests are likely to be localized: along heating circuits, at the entrance to the greenhouse, near central paths. The most effective means of physically controlling pest populations are roll-on glue traps.

The main purpose of this type of trap is mass mechanical catching of pests. Due to the large adhesive surface area, this product is effective both with low and high thrips populations.

What to do with the land?

To prevent thrips colonies from settling on indoor flowers, the air in the room must contain a certain percentage of humidity. Plants should be watered and the soil in the pots should always be slightly damp.

If infected after treatment with insecticides, the soil should be changed to a depth of five centimeters; this guarantees that there are no thrips larvae left in the soil. Since it is difficult to fight them, it is better to follow preventive methods.

Fight against "spies"! For “vagrant” pests, it is worth placing sticky traps in blue, pink, and yellow on flowers. Thrips on indoor flowers are, of course, a big nuisance, but you learned how to deal with them.

By what signs can one suspect the appearance

It is very difficult to determine a thrips infestation at first, since the insects are secretive and can immediately attack not all plants, but only one.

However, there are a number of signs by which one can suspect a lesion:

• The presence of small punctures, cuts on the stems and leaves;
• Discoloration of foliage;
• The appearance of brown or white spots on the back of the leaf;
• Withering, drying and falling off of leaves;
• Abnormal external changes in stems, buds and flowers.

The main signs of the life of thrips are quite unambiguous, but they can only be noticed by careful examination of the leaves. In addition, the last sign of the presence is sticky discharge and black lumps on the foliage - waste products of parasites.