How to Identify and Control Thrips in Fruit Crops
An overview of the thrips that harm vegetable crops is given on this page. Information on their identification, damage, and management is provided in detail by the associated tools listed at the bottom of the page. It's crucial to know how to recognize insect pests like thrips and to get unidentified species properly diagnosed so that they can be handled.
More than 6,000 different kinds of thrips are robbing plants of their life all over the world. Thrips are a frequent pest found in greenhouses and indoor and outdoor gardens. Thrips are small insects that feed on several plants all over the world. They have fringed wings approximately the size of a sewing needle. The sucking insects known as thrips, also known as Thysanoptera or thunder flies, feed on plants and inflict some damage on them as a result of their feeding habits.
Although adult thrips are not good flyers, they are easily spread by wind and on objects like plants, humans, or equipment. Thrips enjoy squeezing themselves into tight spaces. They can also be found on the undersides of leaves, however they are typically found in blooms or the growing tips of young seedlings. Thrips populations in crops can be counted using yellow sticky traps positioned throughout the crop.
How to Identify thrips in fruit crops
These tiny insects, which are frequently described as cigar- or bullet-shaped, are only one millimeter long. Their bodies range from translucent white or yellow to deep brown or black, and their wings contain fringes.
Use a hand lens with a 10x magnification or greater to get a closer look if you notice a tiny, thin insect crawling on flower petals or foliage.
In the field, species identification can be exceedingly challenging. Body color is not a fully precise metric, but you can utilize cues like their behavior, look, and what plant they are feeding on to help identify them as closely as you can.
Engage an expert if you need or want to be certain of the precise species that are present.
When employing an integrated pest management strategy that incorporates biological controls, it can be vital to know the difference even if identical control methods will generally work on most species. This is because some natural enemies provide greater control for some species than others.
Plus, you don't necessarily need to break out the chemicals just because you detect thrips. Many pest species, even those that favor their specific host, are harmless if encountered elsewhere.
For instance, the famed Western flower thrips are known to hang out on avocado plants yet do not harm the fruit.
Here are a few typical varieties you could discover in your garden:
The most prevalent thrips pest of herbaceous plants is the western flower thrips, Frankliniella occidentalis. It is a prominent INSV and TSWV vector.
Larvae, pupae, and adult males are light yellow, whereas adult females range in color from dark yellow to dark brown. The eyes of the larvae are crimson. The translucent white eggs are shaped like kidneys.
Heliothrips haemorrhoidalis, sometimes known as the greenhouse thrips, is widespread in, you guessed it, greenhouses. It adores perennials with thick leaves, like azalea and avocado.
Black adults with yellow wings. Eggs are white and banana-shaped, whereas larvae and pupae are a pale yellow color.
Citrus thrips, Scirtothrips citri, are orange-yellow as adults and can be found on a variety of plants, however they typically exclusively harm citrus and blueberries.
Males are a little bit smaller than females. Larvae range in color from orange-yellow to white, and their white eggs are shaped like bananas.
An eggplant leaf with pests infesting it is seen in close-up on a soft-focus background.
The vegetable-loving melon thrips, Thrips palmi, also makes sporadic visits to garden plants for a nibble.
The larvae, pupae, and adults are a light yellow to white color. The body of the adults are covered in dark-colored hair. Eggs in the shape of beans are either colorless or extremely pale.
Life Cycle and Biology
Five developmental stages are experienced by Thysanoptera species: egg, larva, prepupa, pupa, and adult.
There are two overlapping instars of feeding larvae (instars one and two), as well as two instars of prepupae and pupae that do not feed and spend their lives primarily in the soil.
On or inside of leaves, buds, and other plant tissues, eggs are placed. The larvae feed for four to five days after emerging during each of the first two instar phases.
Prepupae spend one day settling in plant fissures, galls, or the soil by dropping into it or leaf litter. The prepupae occasionally exhibit observable wing buds.
Pupae are rarely observable and remain in the soil until they become adults. After two or three days, they start to show.
An image of mature and young thrips infesting a plant's leaf in close-up horizontal perspective.
Timing of the life cycle is influenced by host, temperature, and species. They may often finish eight to twelve generations every year.
Frankliniella occidentalis, however, develops more quickly in warmer temperatures, maturing from an egg to an adult in just ten days when the temperature is 80°F.
For some Thysanoptera species, sexual reproduction is not necessary and is even uncommon since females can deposit unfertilized eggs that develop into genetically identical females.
Since most people are poor flyers, they are spread on clothing and tools and transported over great distances by air currents.
Thrips will hibernate among garbage and leaf litter.
How to control thrips in fruit crops
Cycle of Life
- The species of thrips, the environment, and the host plant are just a few of the variables that affect how long they live. Thrips overwinter as adults in plant waste, bark, or other substances like leaves and soil. Early in the spring, the females become active and lay their eggs in the plant tissues.
- The 1.4 mm length adults are tiny, slender, soft-bodied insects with strongly fringed wings that are blackish brown with yellowish wings. Adult Scirtothrips Dorsalis are a pale yellow color. The nymphs are tiny and brownish-yellow.
- On the underside of leaves, the female typically lays 50 filthy, white eggs in the shape of beans.
- 3–8 days make up the incubation phase. Nymphs are reddish when they first hatch; as they develop, they turn yellowish brown. The pupal stage lasts for 2 to 5 days.
- Thrips can generate up to fifteen generations in a single year. Adult thrips are thought to live for about a month after birth.
Identifying
Thrips come in a variety of sizes, with the smallest measuring between 0.6 and 15 mm in length, which is a sizable range. They are so tiny that they can fit into even the tiniest crack in a stem or piece of bark, or the smallest flowers. When their wings are present, they are classified as Thysanoptera, which is Latin for "wings fringed," because they have narrow, fringed wings.
The bodies of thrips are very ornately decorated, frequently with hexagonal patterns, spines, or flanges around the body flanges, despite their Lilliputian small. Some bristles have extended or expanded tips, or the body wall may have widened to resemble prongs or forks. Thrips come in a variety of species, each of which can be identified by its vividly colored larvae (red, orange, or yellow), while its adults can be any color from whitish to brown or black. Adults who have bladders that can inflate on the tarsi of their legs are known by the common appellation bladder feet.
Damage indications
Thrips can significantly impact the aesthetic appeal of plants by eating on their fruit, leaves, and shoots in addition to causing damage to those parts of the plant. Despite this, thrips very rarely kill trees or shrubs or pose a threat to their existence. The potential of serious damage to herbaceous ornamentals and some fruit crops is raised due to thrips feeding and thrips-vectored viruses, especially while the crops are young.
It is crucial to be aware that thrips feeding can restrict plant growth, cause distorted and papery damaged leaves, result in tiny pale spots on the leaves (stippling), and hasten the early death of plants. Due to infection, infected plants' terminals may become discolored and rolled. A "color break," also known as a pale or dark discoloration of the petal tissue that thrips have died before bud opening, may be visible in the flower's petals.
Some plants' terminal growth may be severely stunted if thrips emerge at the start of the season. Cuban laurel thrips produce galled foliage and tightly curled, pod-like leaf terminals on Ficus plants from midsummer through the fall. Some myoporum thrips species can form tightly coiled, twisted terminal growths that mimic galls, which serve as a haven for thrip survival and reproduction.
Thrips can leave avocados and citrus fruits with scabby scarring, but they have no effect on the flavor or quality of the fruit inside. When thrips lay their eggs on grapes, the grapes might develop dark scars with darker haloes around them. Thrips may distort or leave scars on developing apples, nectarines, and raspberries. Feeding multiple citrus thrips results in the deformed shoot tips and foliage of blueberry bushes.
When damage has been noticed, such as after the spring buds have opened, many species of thrips may no longer be active. Numerous abiotic conditions, diseases, and other invertebrates can inflict harm resembling that of thrips. In addition to the stippling caused by their feces, some bugs and mites also produce fecal particles that stipple the leaves, and some true bugs also produce dark feces. Before implementing a control strategy, carefully inspect for the insects to ensure that pest thrips are present and are the cause of the damage.
Monitoring
Assume that thrips are to blame for the damage to the plants. Therefore, managing Thrips in this situation is a matter of maintaining the fruit harvest. By gently shaking foliage or stems into a light-colored paper sheet, beating tray, or tiny cloth, one can see the adults and larvae of thrips. To lessen the number of thrips breeding sites, it will be required to remove plant detritus while it is still green and on the ground.
A live plant's stem is slitted where a thrips lays its eggs. Additionally, it's critical to be alert in recognizing issues as soon as possible and taking action. Check your plants for damage and pest infestations where the leaves are linked to the stems. Immediately take action and implement remedies. Additionally, you ought to select tried-and-true, secure products.
Buds and unopened shoot tips can be placed in a jar with 70% ethanol (alcohol) and shaken rapidly to loosen thrips from them. To make it easier to see thrips, the solution should be filtered using filter paper. You can also find adult thrips by placing bright yellow sticky traps close to your host plants.
The mere fact that thrips are present does not guarantee that their feeding will result in damage. Even if there are a lot of thrips in traps or adults eating pollen from flowers, no intervention is always required.
Thrips-vectored viruses can only be accurately identified by sending correctly collected samples from afflicted plants to a lab that checks for plant diseases.
In situations when there are significant pest populations, it can be necessary to employ pyrethrin as a botanical insecticide. A temporary, non-toxic botanical insecticide is pyrethrin. Keep things under control by using predatory insects as a follow-up.
biological defense
Find out if there are any specific natural enemies that can help control thrips when they become an issue. Predatory thrips, green lacewings, tiny pirate bugs, mites, and parasitic wasps are among the insects that aid in the management of plant-feeding thrips. To preserve and promote populations of these advantages that occur naturally, think about frequently rinsing dust off little plants, staying away from persistent chemicals, and growing a variety of plants.
Thrips are mites of the Euseius species, which are among the most significant citrus predators. Up to 50% of the time, a tiny wasp known as Megaphragma Mymaripenne kills the greenhouse thrips egg. After feeding inside the larval stage and pupating, the emerging adult parasite leaves a pretty large spherical hole in a tiny thrips egg.
Predatory thrips, predatory mites, anthocorid bugs, or minute pirate bugs, ground beetles, lacewings, hoverflies, ladybird beetles, and spiders are examples of natural enemies that should be preserved in the orchard to prevent pest infestations.
On the other hand, a portion of the greenhouse thrips' shell is frequently visible at the side of the blister when it hatches from an unparasitic egg. Larvae of greenhouse thrips are parasitized by Thripobius Semiluteus. In contrast to the light hue of an unparasitic greenhouse thrips' larva, a parasitized one develops a swelling around the head before turning black. Unlike healthy, mature black thrips, black parasitized larvae are small and immobile.
Use early in the season to control thrips; do not use on table grapes to treat blossom thrips. Apply to a shoot length of one inch at the start of the season and leave on until it sets. It will guard against shoot damage in the early spring but not berry scarring. Shoot growth is delayed by chilly spring temperatures. In the spring, it also treats powdery mildew and manages mites.
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Apple thrips are controlled using chemicals.
900–1350 grams of Chromobacterium subtsugae per acre. Apply a knockdown insecticide prior to use or in a tank mix, use the considerably higher label rates and reduce the spray interval, or increase the spray volume to better coverage when there are significant thrips populations.
spinetoram applied at a rate of 130 to 200 ml per acre in up to 100 gallons of water. Four treatments should not be overused in one growth season.
Use up to 100 gal of water each application of Spinosad at a rate of 60 to 90 ml per acre. Never go over 260 ml per acre each season.
Use 600 to 800 cc of tolfenpyrad per acre in up to 100 gallons of water per application. view the supplementary label No more than two applications from the air are permitted.
Thrips in citrus fruits can be controlled chemically.
Always take into account an integrated strategy that includes biological treatments and preventative measures where available. Normal healthy trees can tolerate the damage brought on by low thrips numbers, despite the fact that the foliage can be attacked. Gather and eliminate the damaged plant pieces.
During flush growth times, spray malathion 0.05%, monocrotophos 0.036%, or carbaryl 0.1% with systemic insecticides.
encourage the behavior of natural enemies like chysops and syrphids
In non-bearing trees, frequent pesticide applications are not advised since they may result in the development of resistance, making thrips control more challenging in the future. Citrus thrips can be controlled with formulations including abamectin, spinetoram, dimethoate, and abamectin.
Guava thrips are controlled using chemicals.
Use pyrellin (pyrethrins + rotenone) at a rate of 1 to 2 points per acre to combat aphids, caterpillars, fruit flies, leafhoppers, mites, thrips, weevils, and whiteflies. No waiting time before harvesting.
Mango thrips are controlled using chemicals.
Placing blue or yellow sticky traps at regular intervals can help you keep an eye out for thrips infestation. Pesticides made from neem successfully suppress young nymphs, restrict the growth of older nymphs, and lessen the adult nymphs' capacity to lay eggs.
The thrips' early stages can be efficiently reduced by spraying neem seed kernel extract (5%) or neem oil (2%) on the affected area.
Spray insecticides such as thiamethoxam 25% WG (0.3 g/lit), imidacloprid 17.8% SL (0.3 ml/lit), or spinosad 45%SC (0.4 g/lit) if the infestation is severe.
Grape thrips are controlled using chemicals.
Apply Spinosad to the young larvae within the first several days of the eggs hatching. After four or five days, a second application may be necessary in cases of severe infestations. To protect honey bees, you should only use bee spray in the late evening, overnight, or early morning.
Early in the season, it is advised to use Narrow-range oil to manage thrips; do not use it to control flower thrips in table grapes. Apply a 1-inch shoot length of the product during the early growing season and wait till it is completely set. Its early spring application will aid in preventing shoot damage, but it is ineffective for healing scarring on berries. An daily application of this technique is to reduce the rate of growth of shoots in the chilly spring months.
Narrow-range oil is used as a contact treatment for powdery mildew and a mite control in the spring. Use ground-based equipment to make sure the leaf surfaces are completely covered with spray. You ought to repeat the spraying procedure every one to fourteen days. Post-veraison berries may have a residue from late-season treatments. When the fruit is present, avoid using copper, and avoid applying within ten days of sulfur. Look closely at the label for any further use restrictions.
To get rid of the pest, mist late flowering with Dimethoate 0.06% and Acephate 0.1125%. (b) Scirtothrips dorsalis is controlled by two sprays of Monocrotophos 0.05% or Acephate 0.1125% spaced ten days apart and has a similar occurrence and manner of injury as the aforementioned species. Spray with ground-based equipment to completely coat leaf surfaces. Every 1 to 14 days, repeat the spraying.
Post-veraison berries may have a residue from late-season treatments. When the fruit is present, avoid using copper, and avoid applying within ten days of sulfur. Look closely at the label for any further use restrictions.
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Strawberry in Yellow Image Source
Chemical treatment for pomegranate thrips
Spray one liter of water with Dimethoate 30 EC at 1.7 ml, Oxydemeton methyl 25 EC at 1.5 ml, or imidacloprid 17.8 SC at 0.3 ml.
Spraying Dimethoate 0.06% before flowering and, in extreme cases, spraying Methyl Oxy-Demeton 0.05% and again after fruit set, is important.
Spray dichlorovos at 0.05%, imidacloprid at 0.04%, deltamethrin at 0.15, or chlorpyrifos at 0.02% as a preventative measure or as soon as you notice symptoms.
The flowing fluid from the leaves, flowers, and little developing fruits is lacerated and sucked by both nymphs and adults. Spray ready-to-use neem-based insecticides at a rate of 20 ml (1% EC) to 40 ml (0.15% EC) per 10 lit of water as soon as the pest appears. Spray cyantraniliprole 10.26 OD at 10 ml per 10 lit of water when there is a higher occurrence.
Orange thrips are controlled using chemicals.
Normal healthy trees can tolerate the damage brought on by low thrips numbers, despite the fact that the foliage can be attacked. In non-bearing trees, frequent pesticide applications are not advised since they may result in the development of resistance, making thrips control more challenging in the future. Citrus thrips can be controlled with formulations including abamectin, spinetoram, dimethoate, and abamectin.
In organically managed orchards, sprays of formulations of Spinosad with an oil that has received organic approval, kaolin, or Sabadilla alkaloids mixed with molasses or sugar bait are typically advised.
Thrips are controlled chemically in papaya
Additionally, ongoing observation, the application of pongamia oil or soap solutions in badly infested areas, and the prudent application of chemical insecticides and fertilizers are all advised.
Spray 25 EC 2 ml/liter of methyldemeton.
Chemical treatment for watermelon thrips
Applying neem cake to the soil twice (once at germination and once at flowering), then spraying NSKE at 4% with sticker (0.5 ml/l of water) at intervals of 10-15 days.
Sweet lime thrips treatment and chemical control
Petroleum sprays can be used to successfully administer IPM programs in addition to managing thrips with them. It is impossible to emphasize the value of comprehensive coverage. Before using a greenhouse thrips pest control spray, be sure that any immature fruit is not in contact.
Spinosad treatment early in the spring has been seen to reduce insect infestation indicators in trees cultivated organically. Thrips are also treated with a variety of pesticides, but they typically become resistant to them very fast. It becomes obvious that this is a losing battle when there are eight generations per year to contend with. It is crucial to remember that some chemical combinations are intended to kill thrips. Pyrethroid and organophosphate usage is thought to be comparatively non-toxic.
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When thrips have taken over our roses, they are difficult to control. Under the surface of leaves and flower buds, they will conceal themselves. Your fruit crops won't be harmed by thrips if you use the control techniques mentioned above. At the first sign of infestation, preventive measures should be implemented.
