Damage & Plant Injury

Damage and Plant Injury

Some thrips cause damage to leaves, shoots, flowers and even fruit. In the following galleries you will find images of characteristic plant injury as well as some videos on the behaviour of thrips.

This page was created with the help of Klaus Schrameyer (LTZ Augustenberg), who provided most of the photos.
The following species are shown in alphabetical order according to their scientific names:

Dichromothrips corbetti | Drepanothrips reuteri | Echinothrips americanus | Frankliniella intonsa | Frankliniella occidentalis | Gynaikothrips uzeli | Haplothrips aculeatus |Heliothrips haemorrhoidalis | Hercinothrips brunneus | Hercinothrips femoralis | Limothrips sp. | Parthenothrips dracaenae | Sciothrips cardamomi | Scirtothrips aurantii | Taeniothrips inconsequens | Thrips angusticeps | Thrips fuscipennis | Thrips minutissimus | Thrips nigropilosus | Thrips palmi | Thrips pini |Thrips setosus | Thrips tabaci | Thrips urticae

Hercinothrips brunneus

Hercinothrips brunneus was described from northern South Africa and is widespread over large parts of the African continent. It is also commonly found on the Canary Islands. In Europe, it has been reported from the Spanish mainland and from Mallorca. Adults and larvae suck on leaves and cause large silvery spots. This pattern is caused by dry plant cells that are filled with air. Transmission of plant viruses by H. brunneus is not known.
Photos of plant injury and macros by © Mirella Zeeders – Geminiature photography

Hercinothrips femoralis – Sugar Beet Thrips or Banded Greenhouse Thrips

Hercinothrips femoralis is breeding and feeding on the leaves of many different plants, but with a preference of Amaryllidaceae. Originally from Africa, it has been introduced into many other regions by plant trade and iswidespread across the subtropics and tropics. In temperate regions it is usually only found in greenhouses.

Limothrips cerealium & L. denticornis – Corn Thrips, Grain Thrips, Barley Thrips or Thunderflies

Limothrips cerealium has been introduced into many countries with cereals and thus is distributed semi-cosmopolitan today; L. denticornis originates from Europe and Siberia, but has also been introduced into North America and Australia. Both species are found on the ears of grasses, including cereals, and are known be harmful to these crops. Locally, L. cerealium is known to occur in high abundance, with up to 10,000,000 individuals per hectare.
Both Limothrips species are prone to mass flights in summer (see also thunderflies). However, only the females swarm, as the males are wingless. Particularly in areas close to cereal crops, swarming specimens are often carried towards houses by air movement and invade their en masse. Due to their behaviour of crawling into the smallest cracks and crevices (thigmotaxis), they can cause damage, particularly if they perish in objects such as glazed picture frames, photographic slides or clocks. By crawling under beverage caps, these thrips are also known as a hygienic problem, especially when crates are stored outdoors. Furthermore, thunderflies can penetrate technical devices. In fire detectors, they may trigger false alarms and they are frequently considered as “pests” in computer monitors. Attracted by the light, they enter the screens and if they perish there, between the glass and the diffuser film, they remain as an annoying comma-shaped stain that is almost impossible to remove. On the skin, thunderflies can cause itching and and irritation in sensitive people. However, Limothrips species do not actively suck blood but merely soak up sweat and may penetrate the skin accidentally and superficially with their styletts.

Parthenothrips dracaenae – Parlour Palm Thrips

Parthenothrips dracaenae is widespread around the world in tropical and subtropical countries. In temperate regions, however, it is only found under glass or on indoor landscape planting. It is feeding, breeding, and pupating on the leaves of a wide range of plants, most of which have hard leaves. Frequently, P. dracaenae is associated with the leaves of the cultivated kentia palm or parlour palm (Howea forsteriana), but also commonly found on ferns such as Adiantum spp.

Sciothrips cardamomi – Cardamom Thrips

Sciothrips cardamomi originates from tropical Asia and is a destructive pest there. In Europe it is not found outdoors and is not to be expected there. In protected cultivation (under glass) its establishment may be possible if suitable host plants (cardamom, ginger) are available. However, damage is expected to be rather low. S. cardamomi reproduces on young flowers and leaves of cardamom plants. It feeds on seed capsules, flower buds and panicles. The injured tissues form a corky layer on the capsule surface which appear as scales. Such capsules appear stunted, malformed and shrivelled with gaping slits on the skin. The condition is popularly known as “cardamom itch”. Seeds from infected capsules give poor germination. At panicle formation stage, infestation causes stunting of panicles and shedding of flowers.

Scirtothrips aurantii – South African Citrus Thrips

Scirtothrips aurantii is widespread across Africa, but has recently been introduced to Portugal and Spain; furthermore, it has been reported from Queensland, Australia. Although it is common on oranges and other citrus fruits, where it probably causes the most damage, S. aurantii is highly polyphagous and can be found on a wide range of other plants. There are reports from over 70 plant species, including crops such as amaranth, asparagus, banana, cashew, castor bean, cotton, mango, peanut and grapevine. In citrus fruits, the infestation usually forms a ring of scarred tissue around the base of the young fruit, which increases in size as the fruit grows. Injuries to the leaves lead to brownish marks and result in premature ageing. The fruits of navel orange varieties are considered to be the most susceptible to these thrips.

Taeniothrips inconsequens – Pear Thrips

Taeniothrips inconsequens originates from the Palaearctic region, but has been introduced at various times to other parts of the world.
This thrips lives mainly on deciduous trees and shrubs, particularly on Rosaceae and Acer. T. inconsequens is found on its host plants already in early spring. It feeds on young leaves and sometimes also on develloping young fruit. On peach trees (Prunus persica, Rosaceae) and sugar maple (Acer saccharum, Sapindaceae) is a feared pest, causing severe damage to young leaves and premature leaf fall.

Thrips angusticeps – Cabbage Thrips, Field Thrips or Flax Thrips

Thrips angusticeps is widespread in the western Palearctic and is one of the most common species in this region. It is polyphagous and is found on leaves and flowers of many different plants. Particularly in spring, specimens of both sexes occur in brachypterous or hemimacropterous form. T. angusticeps is considered a pest on flax, cereals and peas.

Thrips fuscipennis – Rose Thrips

Thrips fuscipennis originates from the Palaearctic region (with the exception of North Africa), but has also been introduced to North America. In Central Europe it is one of the most common thrips species. T. fuscipennis lives and breeds in flowers and on leaves of many different plants and is frequently found on woody species, especially of the family Rosaceae. It is considered a pest of roses, but can also infest other plants in case of high abundance. Cultivated plants under glass are usually damaged when large numbers of this thrips enter greenhouses from outside and reproduce in suitable monocultures.

Thrips minutissimus

Thrips minutissimus  is widespread and common throughout Europe. It occurs on its hostplants in ealry spring and produces only one generation. T. minutissimus is particularly abundant in shady locations. Mass occurrences are known from beech forests, but this thrips has a wide range of host plants and can be found on many other deciduous trees (particularly on Rosaceae, but often also on hornbeams and oaks). Adults and larvae are usually found on young flowering twigs. Heavy infestation on fruit trees can lead to damage of the blossom and thus to deformation or loss of the fruit. Leaf necrosis caused by T. minutissimus is known to occur on grapevines.

Thrips nigropilosus – Chrysanthemum Thrips or Pyrethrum Thrips

Thrips nigropilosus is widespread across the northern Palaearctic as far as Japan and locally very common. It has also been introduced into many other parts of the world, e.g. East Africa and New Zealand. T. nigropilosus feeds and breeds on many different plants, predominantly however on Asteraceae (Achillea, Chrysanthemum, Pyrethrum, Senecio) and is particularly common in grassy places. Occasionally, T. nigropilosus can be found as a pest on ornamental as well as crop plants (e.g. basil, mint, cucumber, flax, wheat), both outdoors and in glasshouses.
Females occur in macropterous, hemimacropterous or brachypterous form, males are always brachypterous.

Thrips palmi – Melon Thrips, Oriental Thrips or Southern Yellow Thrips

Thrips palmi originates from Southeast Asia, but is now common throughout Asia. Furthermore, it can be found locally in northern Australia and is widespread in different tropical countries, including the Caribbean and southern Florida. In several European countries, T. palmi is listed as a quarantine species which is frequently recorded during incoming inspections of plants or plant products. So far, the species has not been able to establish itself permanently in Europe, even though small populations have emerged from time to time (e.g. in the Netherlands, Portugal and Germany).

In many tropical countries, T. palmi is a feared crop pest. Commonly known as the Melon Thrips, T. palmi is highly polyphagous and occurs on different cultivated plants, particularly on Cucurbitaceae and Solanaceae. It feeds and breeds on leaves and flowers, where damage is caused by sucking. T. palmi is also considered a vector of Tospo viruses (WSMV, GBNV).

Note: Thrips palmi was named after Dr Palm; it is therefore not a thrips that lives on palm trees. Therefore, the term “Palm Thrips” is incorrect.

Thrips pini – European Larch Thrips or European Conifer Thrips

Widespread in Europe and found on conifers such as Abies, Larix, Picea and Pinus. In high abundance, Thrips pini is known as a forest pest on conifers. Adults and larvae suck on needles and shoots. Damaged needles become grayish, curve and fall down. Heavily attacked shoots curve and may die; dying characteristically starts from the top. The most severe infestations and the greatest damage, however, are found on trees that are already weakened, e.g. due to water stress or acid rain.

Thrips setosus – Japanese Flower Thrips

Thrips setosus was introduced to Europe from Asia in 2014. There, it had been recorded in the Netherlands, and was then found in Hamburg, Germany in autumn 2015. By trade with ornamental plants, it was further spread and detected in May 2016 on hydrangeas in southern Germany. T. setosus is mainly found on hydrangeas, however, it is polyphagous, posing a risk of spreading to other plants. In spite of its common name, T. setosus is primarily a leaf-feeding thrips. Besides causing direct damages by sucking, it is also capable to transmit plant viruses such as the Tospovirus.

Thrips tabaci – Onion Thrips or Potato Thrips

Thrips tabaci is found in flowers and on leaves of many different plants. It is highly polyphagous, and can be predatory on small mites on leaves. Economically, T. tabaci is particularly associated with Allium species, but it also breeds on many other vegetable crops, including carrots and cabbages. Until the arrival of Frankliniella occidentalis, the Onion Thrips was the primary pest thrips of commercial glasshouse production in many parts of Europe. This thrips occurs in two biotypes: the biotype on tobacco is considered a strong virus vector (also on other plants such as potatoes), while the biotype on onion plants causes severe sucking damage but does not transmit viruses.

Thrips urticae

Thrips urticae lives and breeds on the leaves of stinging nettles (Urtica dioica). It is a widespread species throughout Europe but not common. It is not considered a pest.