The Lithop family of succulent plants is mainly impacted by the thrip pest. These minuscule pests, which are just 23 mm long, have mouthparts that scrape and pierce plant tissue, enabling the slow ingestion of sap from damaged plants. Additionally, they frequently spend time in the flowerheads of cacti and succulents, where they harm the petals and leave a noticeable mark on the soft-bodied plants.
Even though they are tiny, Western Flower Thrips can easily access the expanding plant head, especially while the Lithops are in bloom. They operate “in masse, swarming in the flower head, feeding on pollen and tearing at the tender new growth’s tissue. The damage often doesn’t become visible on new growth until the following year, when you become aware of the attack. An image of the many stages of thrip larvae is shown above.
Eradication of Western Flower Thrips
This particular pest was first identified in glasshouses in the United Kingdom in the 1980s, when it wreaked havoc on hundreds of different plant varieties. The thrip pest has a varied life cycle with numerous stages, all of which are affected more quickly by an increase in temperature.
Although it is exceedingly difficult to control this bug, a systemic insecticide should be applied in a series of precisely timed administrations over the course of three weeks. One generation of insects will be impacted and eliminated by this, which should solve the issue. Be aware that overusing a particular type of systemic insecticide can make bugs resistant to its effects.
How can thrips on succulents be eliminated?
When it comes to insecticidal soap, there are many possibilities. They are all harmless to people, animals, and essentially everything else that isn’t a bug. Thrips are extremely well-suited to insecticidal soap.
The drawback of insecticidal soap is that it is only effective when moist. That implies that until the insect issue is resolved, you must use it daily.
When using it, use caution since some of them include oil. Burns from oil on leaves are possible. It should be applied in the evening and left on the night.
Even if you’re cheap or impatient, you can produce your own insecticidal soap. It’s as easy as adding a teaspoon of real soap to a quart of water (not a detergent like dishwashing soap). You just need to combine everything and put it in a spray bottle to have chemical warfare at your disposal.
What kinds of plants draw thrips?
The tiny, sliver-like insects known as thrips are indigenous to northwest North America. They are a pest that affects field crops and greenhouses all over the world. Numerous host plants, including as impatiens, fuscia, hibiscus, chrysanthemum, begonias, ivy, petunias, and important food crops, are attractive to them.
Thrips may survive on cacti.
In addition to being an impossible undertaking that takes away from the enjoyment of cultivating plants, trying to get rid of every single insect from produced cactus would also indiscriminately kill both pest insects and benign or even useful insects. Additionally, cacti are less alluring to six- and eight-legged bugs due to appropriate growing techniques. Weak, wasteful plants have more difficulties with pests. Growers that are successful find that control is more satisfying than treatment. Pest management must replace pest control. This is accomplished by keeping a close eye out for pests and estimating their numbers. Flying insects can be caught using strategically placed yellow and blue sticky cards, and crawling insects can be found using a decent magnifying glass.
Before joining the rest of a collection, any new plants should be segregated. In most cases, three weeks is sufficient to identify insect issues. The individual plants can be addressed if issues are found. To get rid of any possibly infected soil, new plants should also be repotted before being released from isolation.
THRIPS
There are thousands of different thrips species, yet they all harm cactus in the same way. Thrips consume food by scraping and rasping the surfaces of fragile stems, but their preferred food source is pollen. The best approach to find thrips is to tap or blow on a bloom. As the swiftly moving insects emerge from pollen sacs and rush to the edge of a petal, thrip-infected flowers will display a flurry of movement. They will then swing over the edge and hide somewhere underground. Pollen grains on flowers in blotches or streaks, as well as malformed and small blossoms, are other indicators. It will look like the cactus epidermis is finely specked with numerous small yellow spots. On flowers, there might be a sprinkling of tiny, black specks that are thrip excrement.
Thrips are tiny, measuring only 0.1 in (2 mm), and they move quickly for their size. They may resemble a short, legless worm to the unaided eye. The only difference between larvae and adults is that adults have wings. Thrips are nearly always present outside during the summer, and they can get into homes and greenhouses through doors, windows, and vents. Pets, people, fresh flowers, and fruits may introduce them into the plant growing area, and they can crawl though standard screening. Thrips are widespread. Each female will lay between 50 and 200 eggs, and reproduction can take place with or without mating. In a few days, the eggs molt, and the larvae start eating plants right away. In 7–10 days, they mature into adults, and the cycle repeats.
Early discovery is essential for thrip management. Low humidity and warm temperatures are preferred by thrips. When it is 90F (32C) or higher, they cause the most damage. I prefer the accuracy of applying a granular systemic insecticide to the soil because many species of thrips spend part of their existence as pupae in the soil.
SPIDER MITES
The most frequent pests of indoor-grown plants are spider mites. Plants with a mite infestation will have little yellow stains scattered throughout them where the mites have been draining plant fluids. On plant tips or in between spines, there may be fine webbing in severe infestations. A pale tan to brown callus will likely scar severely injured plants. Because they are so small, mites can float on the wind. They might even be brought inside on a person’s clothing or a pet’s coat. The easiest way to find them is with a lOx lens; they are about the size of a pinhead. The two-spotted mite is the most prevalent species. It features two dark patches, one on each shoulder, and is yellowish brown to greenish in color. The size of the dots increases with mite age.
A spider mite generation lasts around two weeks at 70°F (21°C) and just one week above 86°F (30°C). Mites become inactive below 50F (10C). The shortening of the days in the fall also causes hibernation to occur. They slink away to slumber in cracks and crevices throughout the winter. In some mites, a warm, heated greenhouse will suppress this instinct, thus some wintertime harm may be evident.
Cinnamon oil is used to make a more contemporary chemical that is used to control mites. It manages every stage, even the egg stage. Field tests reveal that it has fungicidal activity in addition to killing the majority of mites on the first day. After just one application, powdery mildew is controlled for a number of weeks.
MEALYBUGS
Mealybugs are scale insects that are about 0.25 in (6 mm) long and resemble small wood lice. They are protected from water and many water-based pesticides by a fluffy wax coating that waterproofs them. Small masses of woolly, cotton-like material called mealybug nests are tucked away in plant cracks and crevices or their surroundings. Nests may be discovered among dead flowers, between tubercles, or on spines. Mealybugs can live their entire lives in the open on plant surfaces or in the soil near their roots. The possibility of finding eggs and a few wayward adults away from plants can result in reinfection. Because male mealybugs can fly and have wings, an infestation can grow quickly. Control is required rather than a cure.
I favor using a systemic insecticide to address mealybug infestations since it kills both surface-found and soil-dwelling insects. Every insecticide poses a risk and should only be used under extreme caution. Mealybugs that are still alive will develop resistance if the same insecticide is applied repeatedly. The Australian black ladybug beetle Cryptolaemus montrouzieri is sold as a biological control for mealybugs. I found that Cryptolaemus did not do well on cacti since the spines made it difficult for them to easily approach their food.
FUNGUS GNATS
Fungus gnats are little, brown to black flies that fly around plants in the atmosphere. In addition to color, fungus gnats can be identified from whiteflies by their habits. Whiteflies frequently rest more than fungus gnats do, but sticky yellow cards are a useful method to spot an infestation.
A few fungus gnats can be observed emerging from the dirt upon closer inspection. Plants are not harmed or eaten by adults, but larvae cause a great deal of harm. Larval forms inhabit the top 2 in (5 cm) of potting material and resemble small worms. Feeding on organic stuff, like as plant roots, they squirm through the dirt. This root trimming causes little harm to large plants with intricate root systems, but root loss can be disastrous for seedlings. A seed flat can be destroyed by fungus gnats in a few weeks. Non-killed seedlings will grow with stunted development. An insecticidal soil drench that targets the issue at the location of plant damage provides the best management.
WHITEFLIES
Whiteflies have the appearance of tiny, resting white moths. They don’t often fly, and when they do, it’s usually only to hover before landing. Larval forms, which resemble shimmering little white scales, can also be seen on plant surfaces. From larvae to adults, every stage sucks juice from the host plant. The majority of it is excreted as honeydew, a sticky, unpleasant substance, onto plant surfaces. On this honeydew, black sooty mold spreads quickly and can be harmful to the plant.
The greenhouse whitefly and the sweet-potato whitefly are the two species that upset people the most. By closely scrutinizing the mature wings, each can be quickly and easily distinguished. The wings of the sweet-potato whitefly are linked to the sides of its back at a 45-degree angle to the ground, while the wings of the greenhouse whitefly are laid flat on its back parallel to the ground. Knowing the species is crucial since the sweet-potato whitefly is more difficult to manage and may need for repeated chemical applications. The most common method of control is the application of a systemic pesticide to the soil’s surface.
PESTICIDES
Plant caregivers occasionally employ insecticides as a part of a control strategy. When used improperly, pesticides pose health dangers for the three P’s—people, pets, and plants—and are typically regarded as poisons. Take time to accomplish the job properly.
Smallest possible droplet sizes should be used when spraying. Replace a sprayer if it is unable to provide a fine spray. According to studies, every time the size of the spray’s droplets is half, the area it covers increases by eight times. A single drop of liquid spread out appropriately covers 0.3 square inches (2 square centimeters), yet a fine aerosol delivery of the same amount of liquid can cover up to 10 square inches (65 square centimeters). Spray that is delivered as a fine mist will cover more ground with less pesticide, lowering health risks, saving money, and improving the spray’s ability to reach gaps and crevices.
The skin should be covered when spraying. Put on a mask, a hat, long sleeves, and full-length pants. Rubber gloves should be worn when applying solid pesticides or when spraying them. Pharmacies sell disposable gloves and masks for a reasonable price. Other people, animals, and plants are not safe, despite the fact that you are. Exercise caution, and try not to pollute the environment too much.
When blending sprays, always dilute chemicals with reverse osmosis water or distilled water. Numerous insecticides are destroyed before application by hard water with an unbalanced pH. For instance, when diluted with alkaline water, pesticides like organophosphates or carbamates are hydrolyzed and lose their effectiveness.
Spray adjuvants are compounds that increase the effectiveness of sprays. (1) Buffering substances modify a solution’s pH. Acids are used to lower the pH of water because it is frequently overly alkaline. (2) Spreaders, also known as wetting agents, enable sprays to more completely cover plant surfaces. Read the label before adding more of something that may already be there as some pesticide concentrates come with a spreader. (3) Spreader-stickers are even more effective since they hold the chemical against the surface of the plant in addition to serving as a wetting agent. When spraying outside plants, spreader-stickers are necessary because they stop the pesticide from washing off in the rain or during overhead watering. (4) Extenders serve as a sunscreen, shielding compounds from UV rays before they can execute their jobs. Spraying can be done less frequently if the chemical control period is extended in this way.
When applied correctly and safely, pesticides provide more advantages than risks. Each prudent plant caretaker should abide by these ten rules:
Read the label, first. Make sure the chemical is efficient for the issue, that it is diluted correctly, and that it is utilized at the appropriate intervals.
2. Be active. When spraying, shake the spray bottle or tank every so often. The majority of pesticides are suspended and will sink to the bottom. Plants would be harmed by that thick sludge.
3. Never combine pesticides. Plants frequently suffer if many insecticides are applied together rather than separately.
4. Apply the appropriate timing. To minimize waste and the potential for plant injury, spray early in the morning, after sunset, or on cloudy days. Applying chemicals while the air is warmer than 85F is not advised (30C).
5. Spray with caution. Foliar sprays should not be used on the soil’s surface because many of them are not meant to be used around roots. For seedlings, this is particularly true.
6. Keep moisture stress at bay. Watering plants should be done recently. Chemicals can harm plants that are under water stress more easily.
Do thrips enjoy all indoor plants?
Be ready to find thrips on any of your indoor plants because they eat on a variety of plants. The leaves, stems, flowers, and flower buds are all suckers for sap.
Nymphs and adults can both eat plants that are kept indoors. You probably won’t notice them until after the population has significantly increased because they often begin on the undersides of the leaves.
How can I tell if thrips are on my plant?
VISIBLE INDICATORS:
- On the leaves and buds, there are tiny black stipples. Use a magnifying glass to make sure that the black dots on the plants are caused by a thrip rather than another bug.
- You may quickly check for thrips by rubbing a branch or some leaves against some white paper. Thrips will drop to the paper and are then simple to see.
- Another tool is blue or yellow sticky cards. The cards will let you know if there are any thrips nearby because they are drawn to these colors.
Is it difficult to get rid of thrips?
Although it is very challenging to totally prevent thrips, you can reduce populations by clearing plant debris rather than letting pruned leaves, stems, and deadheaded flowers remain on the ground during the winter. To stop eggs from overwintering, cut and kill dead plant stalks as winter approaches.
Keep weeds as far away from your own garden and the regions around it as you can. Thrips, which are easily carried into your garden by breezes, are hosted by a variety of weed species.
Important plants can be covered with fine mesh screening to ward off pests. Vegetables, cane fruits, and other sensitive plants can be covered with fine mesh cloth to keep thrips from taking root. Thrips typically travel by floating on the wind.