Quarantine pests

The Colorado beetle belong to the leaf beetle family, Chrysomelidae. The Colorado beetle reproduces itself quickly and is gluttonous, which makes it a difficult and feared plant pest. The damage to the potato leaf caused by the beetle considerably reduces the harvest.

The adult Colorado beetle is easy to recognise. The body of the beetle is oval or round with characteristic black and white stripes running the length of the body. It has black spots on its head and pronotum. It is about 1 cm long, somewhat larger than a ladybird.

The Colorado beetle’s eggs are yellow to bright orange and around 2 mm long. They are laid in clusters on the underside of the leaf and are difficult to distinguish from ladybird eggs.

Newly hatched Colorado beetle larvae are just under two millimetres long and tomato red in colour. Older larvae are lighter red to orange and can be up to 12 mm long. The larvae are oval or round and have two rows of black dots running down each side of the body.

• Pictures of Colorado beetles (gd.eppo.int)

Symptoms

Adult individuals and larvae both eat potato leaves and, in the case of severe infestation, the Colorado beetles can eat so much that the potato blast becomes completely bare. The beetle also leaves black sticky faeces on the potato leaf.

Distribution

The Colorado beetle is present in North America, parts of Asia and in most European countries.

How they spread

Full-grown beetles and larvae spread with potato plants, tubers and in packages with potatoes. Colorado beetles are also spread in packages with fresh vegetables that come from areas where the beetle is present. Adult individuals can be spread far by wind and even on water.

Risk of misidentification

There are one insect that can be misidentified as a Colorado beetle. The pupas and larvae of the Colorado beetle can be confused with the pupas and larvae of a ladybird.

If you have a Colorado beetle infestation

The Colorado beetle can cause great damage to a potato field. Previous assessments showed that the Colorado beetle could most probably become established in Blekinge, Gotland, Halland, Kalmar and Skåne counties if it were to be introduced. In these counties, the Colorado beetle is a quarantine pest, which requires official measures to be taken if it is found.

If you suspect that you have found a Colorado beetle, its egg or larvae, you must notify the county administrative board or the Swedish Board of Agriculture. Collect and kill the beetles, for example, by putting them in boiling water or the freezer.

• Form: Notify quarantine pests

Epitrix is a genus of small beetles which are flea beetles. The beetles are 1.5–2 mm long and jump away like a flea when disturbed. Four species of Epitrix infest potato plants and can cause great damage to potatoes. Leaves, roots and tubers are infested by beetles and their larvae, and the harvest can be impossible to sell because of the damage.

Symptoms

Adult beetles chew on leaves, creating shot-like round holes. The holes are approximately 1–1.5 mm in diameter. Larvae chew on the surface of the potato tubers. The passages can extend for up to 1.5 cm in the tubers. The tunnels created by larvae can lead to the tuber splitting and the surrounding tissue becomes cork-like.

Distribution

The flea beetles as a group include approximately 180 species, most of which are found in North and Central America. Within the EU, there are a couple of species of Epitrix in Spain and Portugal but we have not yet found any of these species in Sweden.

If Epitrix comes to Sweden, it is likely that they would survive here. Then they would also be a great risk for our potato cultivation.

How they spread

Epitrix spreads through trading with potatoes or through accompanying soil, for example, plants and root crops that come from an area where Epitrix occurs. Trading with potatoes to Sweden from areas in Spain and Portugal where Epitrix is present is insignificant. However, there is a risk that you as a private individual may bring Epitrix home with you if you have potatoes with you from a trip abroad.

If you have an infestation of Epitrix

If you suspect that you have an infestation of Epitrix, you must notify us.

• Form: Notify quarantine pests

The root knot nematodes Meloidogyne chitwoodi and Meloidogyne fallax are closely related species that live in soil and plant material. The nematodes’ life cycle consists of three stages: egg, larva and the adult stage.

Meloidogyne chitwoodi and Meloidogyne fallax have many different species of plant as hosts. The potato is the root knot nematodes’ preferred host, but it can also live on carrot, sugar beet and all type of grass, including cereals. Nematodes are not dangerous for human beings but are a threat to potato crops if they spread.

• Pictures of Meloidogyne chitwoodi and Meloidogyne fallax (gd.eppo.int)

Symptoms

Common symptoms are weak plants with poor growth. This can lead to infection by other diseases and crop yield and losses. Tuber-like swellings can be seen on tubers and roots, so called galls. Potato tubers have dead brown patches in areas underneath the skin.

Distribution

In the EU, they have been found in Belgium, France, The Netherlands, Portugal, Sweden and Germany. In Sweden, nematodes have been found in four areas: Blekinge, Skåne, Halland and Västra Götaland. They also exist outside Europe but import of seed potatoes and soil from countries outside the EU is prohibited.

How it spreads

Nematodes have little ability to move. They are most effectively spread by potato seed and soil from infected fields. Sharing agriculture machines is suspected to be a cause of the spread of nematodes where they were originally introduced through seed.

Prevent spread

Be aware of the risks, and minimise the risks with crop rotation and by only use certified seed potatoes in your cultivation. Make sure to clean machines thoroughly when cooperating on use of machines before they are used in your fields.

If you have an infestation of root knot nematodes

If you are affected by an infestation of root knot nematodes, they must be managed. Management measures must be taken for the field, which often entail black fallow for at least a year and then restrictions against cultivating underground crops until the nematodes have been eradicated.

If you suspect that you have an infestation of root knot nematodes, you must notify us.

• Form: Notify quarantine pests

Difficult to obtain compensation

The current plant protection law only permits compensation in special cases, which makes it very difficult in the case of known plant pests. The Swedish Board of Agriculture has at the behest of the Government made a proposal for a future compensation system. The new compensation system assumes, however, new plant protection legislation, which has not yet been enacted.

Potato cyst nematodes are microscopic eelworms that live in and damage the roots of potatoes. The potato is the potato cyst nematode’s most important host plant, although it may also infest tomatoes and wild plants of the potato family (for example, black nightshade and bittersweet).

Potato cyst nematodes can cause great losses in potato cultivations in the case of major infestations. It is therefore important to take measures to eradicate and prevent spread of the potato cyst nematode before they have time to propagate too much.

There are two species of potato cyst nematodes:

• the yellow potato cyst nematode, Globodera rostochiensis
• the white potato cyst nematode, Globodera pallida.

• Pictures of Globodera rostochiensis (gd.eppo.int)
• Pictures of Globodera pallida (gd.eppo.int)

Symptoms

The symptoms are rather diffuse and include stains with reduced growth and sometimes yellowing or withered potato blast. When infested, the size of the tubers may reduce.

Distribution

Both yellow and white potato cyst nematodes have been present in Sweden for a long time, although the white potato cyst nematode is not especially common.

How they spread

Nematodes are spread as cysts with seed, plants for planting, soil, bulbs, and potatoes for consumption or industrial processing.

If you have an infestation of potato cyst nematodes

If you notice or suspect an infestation of white potato cyst nematodes, you must notify it to the Swedish Board of Agriculture or the County Administrative board.

You must also contact the Swedish Board of Agriculture if you suspect or note that a specific potato variety that has been resistant to potato cyst nematodes is no longer resistant.

You do not need to notify if you suspect that it is yellow potato cyst nematode. Yellow potato cyst nematode is today such a common plant pest in potato cultivation that there is an exemption from the obligation to notify to the Swedish Board of Agriculture.

• Form: Notify quarantine pests

Brown rot is caused by the bacteria Ralstonia solanacearum.

• Pictures of brown rot (gd.eppo.int)

Symptoms

The symptoms can be most clearly seen by cutting through a potato tuber. Yellowish-brown discolouring will then be visible in and yellowish-white bacteria drops will ooze out from the vascular ring without needing to squeeze the tuber.

The disease can also exist in a latent form for several generations of potatoes.

Distribution

Many European countries have detected the bacterium Ralstonia solanacearum.

How it spreads

Brown rot spreads in a number of ways. The foremost common path for spreading is by seed potatoes, but it can also be spread through machinery, equipment, weeds and irrigation water. Bacteria can survive freely in the soil but it is unclear how long they would survive during Swedish conditions.

If you an infestation of brown rot

If you suspect that you have an infestation of brown rot, you must notify us.

• Form: Notify quarantine pests

Potato ring rot is caused by the bacteria Clavibacter michiganensis ssp. sepedonicus.

• Pictures of potato ring rot (gd.eppo.int)

Symptoms

The symptoms can be most clearly seen by cutting through a potato tuber. An infected potato with mild symptoms shows scattered or contiguous yellow spots at the vascular ring. If you squeeze a cut tuber, the yellow-coloured tissue will be pressed out as a creamy ooze. In more severe infestation, the vascular ring may be more liquid and brown-coloured. There are seldom symptoms on the potato blast.

The disease can also exist in a latent form for several generations of potatoes.

Distribution

Potato ring rot is present in many European countries but also in some countries in Asia and in North America.

How it spreads

The most common path for spreading is by seed potatoes. Other paths of infection are the machinery used in the potato field and equipment for sorting and packaging of potatoes.

If you use machines such as potato harvesters which also are used by other potato growers, you must clean and preferably disinfect these machines when moving from farm to farm. It should be noted that cold temperatures does not kill the infection.

If you have an infestation of potato ring rot

If you suspect that you have an infestation of potato ring rot, you must notify us.

• Form: Notify quarantine pests

If you would like to read more

• Brochure: Light ring rot on potatoes – in Swedish

Potato wart disease is a soil-borne disease caused by the fungus Synchytrium endobioticum. The fungus lives as a parasite inside the cells of the potato plant and causes uncontrolled growth. Infestation of potato wart disease leads to a deterioration of the quality of the tubers and the number of tubers decreases.

The fungus’s dormant spores can survive for more than 20 years in soil. Potato wart disease can cause extensive financial losses for the growers which have an outbreak of this disease on the farm.

• Pictures of potato wart disease (gd.eppo.int)

Symptoms

Young tubers that are infected may be spongy and deformed. In older tubers, the eyes are infected which develop warty, cauliflower-like growths. To start with, the warts are white or green but they darken over time. Warts can also be found on offshoots or on the stem bases.

Distribution

There are around 40 different strains of potato wart disease in the world and most of them are spread in the EU.

There are four strains in Sweden: strain 1, 8, 18 and 40. Strain 8, 18 and 40 have to date only been found in eastern Skåne and western Blekinge, while strain 1 is found at a number of places from Skåne up to the counties of Västerbotten and Norrbotten.

How it spreads

Potato wart disease spreads with seeds or soil from fields which are infected with potato wart disease.

If you have an infestation of potato wart disease

If you suspect that you have an infestation of potato wart disease, you must notify us.

• Form: Notify quarantine pests

If you would like to read more

• Brochure: Potato wart disease – in Swedish

The bronze birch borer is a buprestid beetle that infests birch.

Symptoms

The larvae chew tunnels through conducting tissue that transports nutrition in the tree. If the damage is sufficiently severe, the transport of nutrition decreases or ceases and the tree dies. Species of birch that are common in Europe, for example, Betula pendula and Betula pubescens, are very sensitive to infestation.

Distribution

The bronze birch borer originates in North America. They have not been found outside North America.

How they spread

Long-distance spread takes place most probably through transport of infected plants and wood products that are manufactured from infected wood. Wood products are, for example, wood packaging material and dunnage used in transport. The greatest risk is untreated wood products such as tree chips that are used to produce energy, in particular if the chips are stored outdoors close to a stand of birch trees.

Risk of misidentification

The bronze birch borer is similar to the emerald ash borer, Agrilus planipennis, both in appearance and in behaviour except that Agrilus planipennis infests other species of trees. In Sweden, there is Agrilus betuleti which is found on birch trees and which also resembles the bronze birch borer.

If you suspect an infestation by the bronze birch borer

If you suspect an infestation by the bronze birch borer, you must notify us.

• Form: Notify quarantine pests

The citrus long-horned beetle and the Asian long-horned beetle are large beetles that live in deciduous trees. The trees are damaged and eventually die as the larvae chew large tunnels in the wood. They both infest deciduous trees of various species.

The different species resemble one another in their appearance but have somewhat different way of life.

• the citrus long-horned beetle lives in the lower part, in the trunk and roots of deciduous trees with a trunk diameter exceeding 1 cm.
• the Asian long-horned beetle needs larger trees with a trunk diameter larger than 5 cm. The species moreover lives higher up in the trunks and in treetops.

• Pictures of citrus long-horned beetle (Anoplophora chinensis) (gd.eppo.int)
• Pictures of the Asian long-horned beetle (Anoplophora glabripennis) (gd.eppo.int)

Symptoms

If you see large exit holes (around 10‑15 mm in diameter) in trees that you have purchased in the past three years, or chewed sawdust on the ground, it may be an indication that there are pests in the tree. You should also be suspicious if you find larvae tunnels that are larger than three mm in wood packaging which originates from areas where the pests are known to be present.

Distribution

They originate from China, but the long-horned beetles are also found in the Philippines, Japan, Indonesia, Korea, Malaysia, Myanmar, Taiwan and Vietnam.

The citrus long-horned beetle has become established in Lombardy in northern Italy and can no longer be eradicated.

The Asian long-horned beetle has spread on repeated occasions in Europe, often from larvae that have arrived here in wood packaging material in connection with import from Asia, in particular China. This has caused large costs due to destroyed trees and massive inputs of labour for pest management. The most recently known case of infestation was at an industrial estate in Finland in the late autumn of 2015. The Finnish authority has noted that the insect reproduced at the location. The agency worked to eradicate the insect and has not found any new infestations of beetles since April 2016.

We have not found any citrus long-horned beetles or Asian long-horned beetles on trees in Sweden. If the long-horned beetles were to be introduced into Sweden, they could survive and reproduce in Götaland and the coastal regions up to the lake Mälaren area.

How they spread

Long-distance spread of eggs, larvae or pupas occur through trade with infested wooden material such as wood packaging material and dunnage.

Risk of misidentification

The citrus long-horned beetle or Asian long-horned beetle is often confused with Monochamus sutor, which are common in Sweden.

• SLU Swedish Species Information Center’s (Artdatabanken) pictures of Monochamus sutor (artfakta.se) – in Swedish

If you suspect an infestation of Asian long-horned beetle

If you suspect an infestation of citrus long-horned beetle or Asian long-horned beetle, you must notify us. You must contact us if you find living larvae or insects in wood packaging material from countries outside the EU.

• Form: Notify quarantine pests

The red-necked longhorn beetle is a long-horned beetle that lives in forests, urban areas and in orchards. They infest, live in and cause damage to trees of the plum family, such as bird cherry, cherry, damson, bird berries and plum. The beetles can be found both in living plants and in timber, wooden products and wood packaging material.

In the event of an infestation in Sweden, it is most important that the infested tree is taken down and destroyed. If this pest became established in Sweden, it would entail serious consequences, both through damage to trees and the financial consequences.

The flight period for the red-necked longhorn beetle is from March to August with an intensive period from May to mid-July. The adult female lays eggs in cracks in the bark in the lower part of the trunk, at most 30 cm above the ground but also in larger branches.

• Pictures of the red-necked longhorn beetle (gd.eppo.int)

Symptoms

It is easiest to detect infected trees when the larvae have their most active period. Reddish chewed sawdust from larvae after hatching can then be found. The chewed sawdust is on the ground by the tree together with the larvae’s feces.

The larvae damage the tree by chewing on and beneath the bark and on the wood. They create tunnels in branches and the trunk which prevent the passage of nutrition in the tree. The clearest symptom is round exit holes that are most often located on the trunk at about 30 cm above the ground.

Distribution

The beetle has been present historically in China, North and South Korea, Mongolia and Vietnam. More recently, the red-necked longhorn beetle has been found in Japan and at three places in the EU, Italy (the Campania and Lombardy regions) and in Germany (Bavaria).

How it spreads

It can spread through trade with plants, wood, wooden products and wood packaging material from infested areas.

Special rules for import to the EU and movement within the EU

As the pest has probably been spread through plants, wood, wooden products or wood packaging material of the Prunus family, there are rules on imports to the EU and movement within the EU from countries where the beetle is present.

If you intend to import plants for planting or move such plants within the EU, there are special rules for plants whose trunk or root crown diameter is at least 1 cm at the thickest point. These plants are large enough for the long-horned beetle to go through a complete life cycle.

Risk of misidentification

The goat moth (Cossus cossus) which lives on deciduous trees, including the species that the red-necked longhorn beetle infests, can also give rise to a collection of feces on the ground by the tree. However, there is no risk of misidentification if one sees individual goat moths as they do not at all resemble the red-necked longhorn beetle.

If you suspect an infestation by the red-necked longhorn beetle

If you suspect an infestation by the red-necked longhorn beetle, you must notify us.

• Form: Notify quarantine pests

Dendrolimus sibiricus (the Siberian conifer silk moth) and Dendrolimus superans (the white-lined silk moth) are two closely related lappet moths which infest different species of coniferous trees.

• Pictures of Dendrolimus sibiricus (gd.eppo.int)

Symptoms

Larvae can cause noticeable defoliation of infested pine trees, larches and spruce trees. The larvae of Dendrolimus sibiricus (50‑80 mm) and Dendrolimus superans (60‑82 mm) are large and visible.

Distribution

Both these pests originate from Asia, and Dendrolimus sibiricus has spread to central Russia.

If they were to become established in Sweden, this could have serious consequences as the Swedish coniferous species and the Swedish climate are favourable for both lappet moths.

How they spread

Natural spread can occur over long distances, as adult lappet moths can fly up to 100 km per year. Transport of all phases of life can take place on host plants or cut branches from, for example, a spruce tree. Also transport of round timber which has not had its bark removed, wood packaging material and dunnage from areas with infested trees could bring lappet moths with them.

Risk of misidentification

In Sweden, there is the pine-tree lappet Dendrolimus pini which is very similar, Dendrolimus sibiricus.

• ASLU – Swedish Species Information Centre’s information and pictures of pine-tree lappets (artfakta.se) – in Swedish

If you suspect an infestation of Dendrolimus sibiricus and Dendrolimus superans

Dendrolimus sibiricus is a quarantine pest. If you suspect that you have an infestation, you must notify the Swedish Board of Agriculture.

We also encourage you to notify suspected incidences of Dendrolimus superans. This is not a quarantine pest and you are accordingly not obliged to notify, but it is a pest which has not been found in Sweden before.

• Form: Notify quarantine pests

The fungus Fusarium circinatum can infest all parts of pine trees and cause serious damage. It can also infest Douglas firs.

Another name for Fusarium circinatum is Gibberella circinata.

Symptoms

The fungus can cause great damage at seed beds in nurseries in the form of low propagation of plants. The fungus causes canker wounds on branches and trunks exuding strong flows of resin. Brown rot is visible in the canker wounds, which often extends around the branch. The branch dies above the infestation point.

Distribution

In Europe, the fungus is present in forests in northern Spain. It has also been found in France and Portugal.

How it spreads

Plants and seed are the most important paths of infection over great distances. Locally the fungus is spread by the wind and insects.

The risk of it spreading to Swedish forest plant nurseries is small since we do not use seed from areas where the fungus occurs. The fungus does not either thrive in our cold climate.

If you suspect an infestation by Fusarium circinatum

If you suspect an infestation by Fusarium circinatum, you must notify us.

• Form: Notify quarantine pests

The Japanese beetle infests over 300 different species of trees, bushes and agricultural crops. Adult individuals infest leaves, fruit and flowers while larvae infest roots and sometimes grass.

• List of host plants (gd.eppo.int)

The beetle has a charismatic appearance that is easy to recognise. It is oval in shape and metallic green with a bronze shell. There are five white tufts of hair on each side of its shell and a couple of white tufts at its rear end. The Japanese beetle is 8–11 millimetres long and 5–7 millimetres wide.

Symptoms

Adult individuals like to infest the sunlit parts of host plants where they chew holes on leaves and the petals of flowers. The Japanese beetle is gregarious and creates clusters when there are a number of individuals. Clusters of beetles can be seen on infested leaves, flowers or fruit. The infestation usually begins at the top of the plant and the beetles then work their way downwards. In the event of severe infestation with a large number of beetles, they can chew the leaves so much that only the midrib remains. Infested leaves turn brown and may fall off. Whole plants can be eaten up if there is a large beetle population.

The larvae cause damage by chewing on the roots of the host plants, giving rise to various symptoms depending on the variety of plant.

Symptoms appear on infested grass such as thinner growth or withered sections or brown patches where the grass has died.

• Pictures of Japanese beetles and symptoms (gd.eppo.int)

Distribution

The beetles are spread in Japan, Canada and in USA. It has also been found in eastern Russia, Italy, Portugal and Switzerland.

How it spreads

It spreads through international trade, in particular with plants for planting, plant products, in packaging or hitching a ride on, for example, boats and aircraft. Larvae can be transported in soil around plants for planting, for example, grass rolls.

When Japanese beetles have been introduced and become established in an area, they can spread by themselves. Adult individuals can fly up to 8 kilometres but most of them do not fly more than 50 metres at a time. In ongoing outbreaks in Italy, the beetle has a spread rate of about 10 kilometres a year.

Risk of misidentification

I Sweden, there is the garden foliage beetle Phyllopertha horticola which resembles the Japanese beetle to some extent. However, the garden foliage beetle lacks the white tufts of hair along its shell and at its rear which the Japanese beetle has.

• Pictures of the garden foliage beetle (gd.eppo.int)

If you suspect an infestation of Japanese beetles

If you suspect an infestation by Japanese beetles, you must notify the Swedish Board of Agriculture.

• Form: Notify quarantine pests

Chestnut blight on a sweet chestnut is a serious fungal disease which damages the tree severely or kills it. Once the disease is introduced, it is difficult to eradicate.

The chestnut blight does not infest horse chestnut trees.

• Pictures of chestnut blight (gd.eppo.int)

Symptoms

The branches have light brown deep wounds, and ragged wounds can appear on trunks of the infested trees. The fungus can grow so quickly that the branches are ring barked without a callous forming around the wound. The trunk or the branches above the wound die and the withered leaves remain on the dead branches.

There are fruiting bodies around the wound on the bark (pycnidia), which form spores. In damp weather, the spores push out, which can look like yellowish orange threads. The spores are the part of the fungus that is spread and can infect healthy trees. Under the bark in the wound, there may also arise a pale brown fungal mycelium in the form of a fan.

Distribution

Chestnut blight exists in most European countries, Australia and some countries in Asia, the Middle East and North America.

How it spreads

The chestnut blight is spread over long distances through trading with plants and timber made of sweet chestnut. The fungus spreads over shorter distances by wind, water and insects.

If you suspect an infestation by chestnut blight

If you suspect an infestation by chestnut blight, you must notify the Swedish Board of Agriculture.

• Form: Notify quarantine pests

Phytophtora ramorum is referred to as a water mould fungus. The plant disease has been shown to infest a large number of different varieties of plants and we continually find new species that are host plants. It is very difficult to manage the disease and there can be major financial and ecological damage if the fungus becomes established in Sweden.

• Pictures of Phytophtora ramorum (gd.eppo.int)

Symptoms

The symptoms vary considerably and may include withered leaves, shoots and branches and wounds on the lower part of the trunk, which are hollowed out and extrude a reddish-brown liquid.

Distribution

The disease is spread over large parts of Europe and USA. In Sweden, we have only detected a few cases of Phytophtora ramorum on Rhododendron purchased from other EU Member States.

How it spreads

Long-distance spread takes place through trade with special ornamental plants such as Rhododendron and Viburnum from countries where the fungus exists. Trade with bark, timber and soil from infected areas can also spread Phytophthora ramorum.

If you suspect an infestation by Phytophthora ramorum

If you suspect an infestation by Phytophthora ramorum you must notify the Swedish Board of Agriculture.

• Form: Notify quarantine pests

The plum curculio is a weevil which infests rose family plants, such as roses, apples, plums, cherries and pears. The weevil has also been found on plants of the currant family and the blueberry family.

Adult individuals are approximately 7 millimetres long with a snout and reddish-brown shell with black granular markings. If the weevil is disturbed, it pretends to be dead and falls to the ground.

Symptoms

Adult individuals chew on flowers, leaves and unripe fruit. When infesting unripe fruit, the weevil causes characteristic egg laying wounds in the shape of a crescent or a swallow. These infestations lead to fruit dropping prematurely, with the exception of cherries where the unripe fruit develops to ripe cherries on the tree. There may be small exit holes on the dropped fruit caused by the weevil’s larvae.

• Pictures of the plum curculio and typical egg laying wounds and scars (gd.eppo.int)

Distribution

The plum curculio is present in Canada and the USA.

How it spreads

It spreads through international trade and then most probably as pupas in soil or adult individuals in packaging material. Spreading through infested fruit with the exception of cherries is less probable as the infestation leads to premature fruit drop.

Risk of misidentification

There are over 400 species of weevils in Sweden and a risk of possible misidentification therefore exists.

If you suspect an infestation by plum curculio

If you suspect an infestation by plum curculio, you must notify the Swedish Board of Agriculture.

• Form: Notify quarantine pests

Rose rosette virus (RRV) infests all plants belonging to the rose family.

• Pictures of rose rosette virus (gd.eppo.int)

Symptoms

Symptoms on roses can vary. Most common is abnormal growth. You can see growth, for example, in the form of:

• thick trunks so that the plants resemble succulents
• increased leaf production
• misshaped leaves
• leaves that have patterns in different nuances of green (referred to as mosaic)
• shoots with marked red pigmentation
• misshaped flower buds and flowers.

Infected plants are less winter hardy and the disease causes a gradual decline in the plant’s health. The plants die within 1 to 5 years after infection.

Distribution

The virus is present in India, Canada and the USA. The virus is widespread in the USA where an increased occurrence has been seen in roses.

How it spreads

The virus is spread in the following ways:

• a gall mite, Phyllocoptes fructiphilus
• mechanically through, for example, pruning or grafting
• trade with infected plant material.

If you suspect an infestation by Rose rosette virus

If you suspect an infestation by Rose rosette virus you must notify us.

• Form: Notify quarantine pests

The emerald ash borer is a beetle that infests ash trees. As the ash is a common tree species in Sweden, an establishment of Agrilus planipennis could have major ecological and financial consequences.

• Pictures of the emerald ash borer (gd.eppo.int)

Symptoms

The larvae eat the cambium layer under the bark of ash trees. The damage caused by chewing leads to foliage being thinned out or turning yellow and branches that wither and die. Infestation by the emerald ash borer leads to the tree dying after a few years. The exit holes created by adult beetles in infested trees are characteristically D-shaped. There are no other jewel beetles in Europe that infest ash trees and cause damage similar to that caused by the emerald ash borer.

Distribution

The beetle originated in East Asia but has spread to Canada, the USA and Russia and most recently to Ukraine. In Canada and the USA, Agrilus planipennis has caused great destruction of ash trees, which are a common component of urban environments as avenue trees. The beetle is not found in Sweden at present.

How it spreads

Long-distance spreading takes place through trade with plants and wood products such as timber, wood packaging material, dunnage, wood chips and wood. In the USA, most observations of the emerald ash borer have been in connection with import of dunnage. The emerald ash borer can moreover fly up to 1 km and in this way spread locally.

If you suspect an infestation by the emerald ash borer

If you suspect an infestation by the emerald ash borer, you must notify us.

• Form: Notify quarantine pests

If you would like to read more

• Factsheet: Agrilus planipennis (gd.eppo.int)

The pine wood nematode is a millimetre long round worm that can cause extensive forest death. It lives in trees and damages the tree’s canal system so that it can no longer take up water.

• Pictures of the pine wood nematode (gd.eppo.int)

Symptoms

The needles first turn yellow before withering and falling off. The infected pines can ultimately die.

Distribution

Nematodes spread in nature with the aid of various species of Monochamus. If we were to get nematodes in Sweden, there are monachamus beetles that can spread the infestation.

How it spreads

The nematodes spread long distances through infested wood or wood packaging material made from infested wood which is transported. We risk introducing the infestation to Sweden in this way.

The pine wood nematode was discovered for the first time in Europe in 1999 and is now established in Portugal, on the mainland and the island of Madeira. The pine wood nematode has also spread to Spain. An infected tree was found in Extremadura in 2008. Since then, three new infestations have been found in Spain. These are small outbreaks of the pine wood nematode and Spain has succeeded in eliminating three of these cases by pest management. It is therefore untreated wood from Portugal which is the greatest risk.

If you suspect an infestation by the pine wood nematode

If you suspect an infestation by the pine wood nematode, you must notify us.

• Form: Notify quarantine pests

Saperda candida is a beetle that belongs to the long-horned beetle family. In Sweden, there are other species of the Saperda family, which are referred to as "wood bocks". Saperda candida primarily infests apple trees but also other trees and bushes that belong to the rose family can be host plants.

If the apple tree borer were to be introduced and spread in Sweden, it could entail serious financial consequences for, in particular, apple orchards, but also for nurseries as a number of fruit trees and bushes may be affected.

• Picture of Saperda candida (bugguide.net)

Symptoms

The larvae cause the greatest damage by chewing tunnels, in particular in the lower part of the trunk on both healthy and weakened wood. The chewing of the larvae can also cause ring barking of the trunk and ultimately the death of the tree.

Distribution

Saperda candida is native to North America and is not found in Sweden at present. The pest has only been found once outside its natural area of dispersion, in North Germany.

How it spreads

Long-term spread most probably takes place with crops for planting. There is also a risk that wood can carry the pest.

If you suspect an infestation by Saperda candida

If you suspect an infestation by Saperda candida, you must notify us.

• Form: Notify quarantine pests

Xylella fastidiosa is an aggressive bacterium that causes extensive damage to plants. The bacterium has many different host plants and more have been detected as we have gained more experience. It causes great damage to various crops such as cherries, plums, olives, grapes and citrus fruit as well as oak, elm and ornamental plants. The bacterium has also been found, for example, in rosemary and myrtle.

Symptoms

The symptoms are very varied and infected plants can be symptom-free. The symptoms may include yellowing and dying leaves or withering of leaves or plant parts. If a fruit tree is infested, the size of the fruits may be reduced.

Distribution

The bacterium originates in the USA and Latin America. At present, damage from the bacterium has been noted in certain areas in Italy, France and Spain. Xylella fastidiosa has probably arrived in southern Italy with coffee bushes imported as ornamental plants from Costa Rica.

How it spreads

The bacterium is spread to new places with the aid of special plants and insects. One of the insects that spread the bacterium is the meadow spittlebug, Philaenus spumarius.

The import of ornamental plants is the most probable scenario for how both Xylella fastidiosa and insects that carry the bacterium could spread to Sweden.

If you suspect an infestation by Xylella fastidiosa

If you suspect an infestation by Xylella fastidiosa, you must notify us.

• Form: Notify quarantine pests

If you would like to read more

• Om Xylella fastidiosa (eppo.int)
• The European Commission’s host plant list for Xylella fastidiosa (ec.europa.eu)

The apple maggot is a fruit fly which mainly infest apples but also species of the hawthorn family.

Adult flies are 4–5 millimetres long with a wing span of 7.5–9 millimetres. The body is mainly black with a white marking on the back and three lighter stripes over its rear end. The wings are transparent with black stripes which characteristically form the letter F.

Symptoms

Adult individuals lay eggs in fruit. Infested fruits appear crumpled or scarred as a result of repeated egg-laying wounds. Some discolouring is visible around the wounds. The larvae in the fruit damage the pulp and cause brown-coloured streaks.

• Pictures of the apple maggot and symptoms (gd.eppo.int)

Distribution

The apple maggot is present in Canada, Mexico and the USA.

How it spreads

It spreads through international trade and transport of infested fruit or soil that contains pupas. Once the fly has been introduced, it can fly further and establish itself in new areas. The apple maggot is able to fly as far as 4.5 kilometres.

Risk of misidentification

In Sweden, there is the cherry fruit fly Rhagoletis cerasi. The cherry fruit fly has a yellow marking on its back instead of white and the wing bars do not form the letter F as in the apple maggot.

• Pictures of the cherry fruit fly (gd.eppo.int)

If you suspect an infestation by the apple maggot

If you suspect an infestation by the apple maggot, you must notify the Swedish Board of Agriculture.

• Form: Notify quarantine pests

The silverleaf white fly is a millimetre-long insect.

The silver leaf white fly can affect more than 300 different plant species, including our common greenhouse vegetables and many potted plants and plants for planting. As well as poinsettia, begonia, fuchsia, gerbera, hibiscus and verbena are mentioned. Bemisia tabaci has shown itself able to spread up to 60 different viruses where gemini virus is the family that causes the greatest economical losses.

Sweden is a protected zone for Bemisia tabaci (European populations), which means that the country shall be free from the pest or actively work to eradicate it. Plants or plant products brought into Sweden from another EU Member State of from a country outside of the EU must not contain silverleaf white flies. Plant material to the end customer need not, however, be wholly free from the pest.

• Pictures of the silver leaf white fly (gd.eppo.int)

Symptoms

The symptoms caused by the silver leaf white fly can be confused with those caused by the greenhouse white fly, Trialeurodes vaporariorum. The greenhouse white fly is relatively common in Europe.

The silver leaf white fly’s nymphs and adult insects sit on the underside of leaves and suck juice from the host plant. This leads to yellow (chlorotic) spots. Excrement from the sucking lice, referred to as honeydew, dirties the plants and provides a breeding ground for sooty mould fungus which hinders growth. Additional symptoms that appear if the lice have spread virus can be that leaves rolling, become yellow, or develop patterns in various nuances of green, (referred to as mosaic) or that the leaf nerves become yellow.

Distribution

The silver leaf white fly is spread in Europe, but also in all other continents. The silver leaf white fly is not established in Sweden as we have to date succeeded in eliminating infestation by management and decontamination.

How it spreads

Long-distance spreading takes place through trade with infested plants for planting and cut flowers. In particular, trade with poinsettia is responsible for much of the spread of the silver leaf white fly in Europe and the Mediterranean countries. Adult lice are not good at flying but once they are in the air, they can be spread long distances transported by the wind.

If you suspect an infestationd by Bemisia tabaci

The silver leaf white fly is a quarantine pest in Sweden and there is thus obligatory notification. If you notice infestation by the silver leaf white fly, you must accordingly notify us.

• Form: Notify quarantine pests

Melon thrips, Thrips palmi, is a thrips and a serious pest that infests many different plant species. The cucumber plants families, sugarpea plants families and potato plants are heavily affected. Among ornamental plants, chrysanthemum, cyclamen and orchids are affected. Green plants such as benjamin ficus can also be infested.

Thrips palmi has become resistant to some common pesticides and is therefore difficult to manage. In Japan, there has been successful application of biological management where, among other things, predatory mites has been used. In Australia, insect soap is recommended when cultivating vegetables.

• Pictures of Thrips palmi (gd.eppo.int)

Symptoms

The thrips empties the cells of plant juice and empty cells give rise to typical thrips symptoms where the cells have a silvery appearance. Leaves, shoot tips and flowers show silvery lines and spots which later dry out and become brown. This is most apparent along the leaf nerves. In the event of severe infestation, the leaves appear to be silver or bronze coloured. Moreover, leaves, fruit and shoot tips become misshapen and crumpled.

Distribution

Thrips palmi originates in south-east Asia and has spread over large areas of Asia and been found in certain African countries, Australia, Iraq, South America, West India, Hawaii and Florida. There have been occasional infestations in greenhouse in Europe but no permanent establishment has taken place.

How it spreads

Long-distance spreading takes place through infested plants for planting, fruit or in packaging that the plant material is packed in. Thrips palmi has been found a number of times in consignments to European and Mediterranean countries through import control of host plants. Thrips palmi has a limited ability to long-distance spread by itself.

Risk of misidentification

Thrips palmi is just over a millimetre log and resembles in its body shape a carnation thrips, Thrips tabaci, which is the common species in Swedish greenhouse cucumber. Expert assistance is needed for sure identification.

• Pictures of carnation-thrips Thrips tabaci (cabi.org)

Thrips palmi can also be confused with Thrips flavus, a relatively common thrips. Microscopic investigation is required to be able to distinguish Thrips palmi from Thrips flavus.

• Pictures of Thrips flavus (keys.lucidcentral.org)

If you suspect an infestation by Thrips palmi

If you suspect an infestation of Thrips palmi, you must notify us.

• Form: Notify quarantine pests

Tomato brown rugose fruit virus (ToBRFV) is a tobamovirus and a pest that infests bell pepper and tomato plants and causes great damage. The tobamovirus is known for being a long-lived virus that can survive for a long time outside its host plant.

• Pictures of tomato brown rugose fruit virus (gd.eppo.int)

Symptoms

The symptoms are most prominent on leaves and fruit. The most common symptoms are:

• leaves patterned in different nuances of green (known as mosaic)
• misshaped leaves
• dried flower sepals and stalks which lead to fruit drop
• necroses on flower sepals and stalks
• yellow spots and necroses on tomato fruits.

Distribution

The virus is found in Mexico, China, Israel, Jordan and Turkey. The virus has recently caused outbreaks in tomato cultivations in France, Greece, Italy, The Netherlands, Spain, the United Kingdom and Germany.

I Mexico, cultivation of bell peppers has been hard hit but in Europe where peppers are grown with the L-resistant gene, peppers seem not to be affected.

How it spreads

Long-distance spread takes place mainly through trade with infested plants for planting and seeds. The virus is spread mechanically at greenhouses by pruning or other treatment of the plants. In the course of outbreaks, the virus can also be spread by pollinators such as bumble bees.

If you suspect an infestation by ToBRFV

If you suspect infestation by ToBRFV, you must notify us.

• Form: Notify quarantine pests