Proposed imports of mangosteen and rambutan plants for planting

• Level 2 PEQ for at least 6 months and 3 shoot flushes.
• Controls on irrigation and drainage during quarantine.
• PCR test during quarantine.
• General requirements that apply to all imported bare-rooted whole plants.

Mangosteen plants from Malaysia could have a water mould. We think the chance of this is small, because we found only one report (from 1994) describing the pest on mangosteen plants and only one record (from 1971) of the mould in Malaysia.

This mould can spread through water, but it can be contained in Level 2 PEQ if irrigation water is collected and treated before it is released from the quarantine facility.

Even though this water mould is not usually associated with mangosteen, it has a wide host range that includes stone fruit, kiwifruit and citrus. We are proposing measures because the mould would have high impact on these hosts if it is established in New Zealand. PCR testing in post-entry quarantine will give us extra certainty that plants do not have this water mould.

Water mould
(Phytophthora palmivora)

Level 2 facilities can manage and contain these other fungi.

The root rot fungi live on roots of the plants and might not be managed by general requirements. However, at some point during 6 months of active growth, plants are likely to show visible symptoms if they are infected with these fungi. Both of these fungi are primarily tropical species, so the possible impacts of these species on New Zealand is low.

P. cruenta can be airborne, but infected plants will show visible symptoms before export or on arrival because this fungus lives on leaves. This fungus has been found in trees grown for timber such as pine and eucalyptus, but we have no reports of yield loss.

The likelihood that these fungi will be present in the imported plants is low because we don’t have evidence of them not showing any symptoms. Diseased plants will not get certificate from the exporting government as that does not meet our import requirements.

There is a chance they could be infested with the root rot pathogens but still not have visible symptoms during quarantine because early infections on the roots might be missed. Both the likelihood of that happening and the possible impacts of these pests on New Zealand are low. The extra certainty that we would get from testing for these pests does not justify the cost of testing.

Red root rot fungus
(Ganoderma philippii)

Brown root rot fungus
(Pyrrhoderma noxium)

Other fungi
(Pestalotiopsis cruenta)

The general requirements for all nursery stock greatly reduce the risk of many pests that could come with the plants, including nematodes.

Insects

Mites

Nematodes

• Level 2 post-entry quarantine for at least 6 months and 3 shoot flushes.
• PCR test during quarantine.
• Controls on irrigation and drainage during quarantine.
• All leafless cuttings must be dipped in 1% sodium hypochlorite for a minimum of 2 minutes on arrival at the quarantine greenhouse.
• General requirements that apply to all cuttings.

Mangosteen leafless semi-hardwood cuttings from Malaysia could have a water mould. However, it is less likely to be present on cuttings because it mostly lives in roots and soil.

We have also found only one report from 1994 describing this association, and one record of the mould in Malaysia from 1971. We are still proposing testing for this mould because it could impact commercially important crops such as stone fruit, kiwifruit, and citrus.

This mould can spread through water, but it can be contained in Level 2 PEQ if irrigation water is collected and treated before it is released from the quarantine facility. PCR testing in post-entry quarantine will give us extra certainty that plants do not have this water mould.

Water mould
(Phytophthora palmivora)

Cuttings need at least 6 months and 3 shoot flushes in Level 2 post-entry quarantine to manage the risk from P. cruenta.

This fungus can be airborne, but infected plants are likely to show visible symptoms before export or on arrival because this fungus lives on leaves. Diseased plants will not get certificate from the exporting government as that does not meet our import requirements. This fungus is also likely to be detected within 6 months of quarantine because the plants are likely to develop visible symptoms if infected with it, further lowering the risk.

This fungus affects trees grown for timber such as pine and eucalyptus, but we have no reports of yield loss.

In the unlikely situation that an infected plant is unknowingly released into New Zealand, we expect the overall impact to New Zealand to be low. The low impact does not justify a higher level of PEQ or testing.

Fungi

(Pestalotiopsis cruenta)

Fungi that cause root rot are normally on roots and are unlikely to be on cuttings. Sterilising the surface of cuttings will manage the risk as it will likey kill any spores that may be present on the cuttings.

Red root rot fungus
(Ganoderma nephelii)

Brown root rot fungus
(Pyrrhoderma noxium) 

• Tissue cultures should only be derived from new aerial plant material.
• Plants derived from tissue cultures will be transferred to Level 2 PEQ and grown for at least 3 months.
• Each plant must have 3 shoot flushes.
• General requirements that apply to all tissue culture.

We want to prevent a fungus called P. cruenta entering New Zealand on mangosteen tissue culture. This fungus mostly lives on leaves and expresses visible symptoms. Tissue cultures are unlikely to be created from visually symptomatic diseased plants. To further reduce the likelihood of this fungus being present in tissue cultures, we want to require tissues cultures to be derived only from new aerial plant materials.

While it is unlikely that this fungus will be present in tissue culture, we would like to prevent from it entering the country as it can impact trees grown for timber such as pine and eucalyptus. So we are proposing tissue cultures to spend time in Level 2 post-entry quarantine for at least 3 shoot flushes to reduce the residual risk.

We have no reports of yield loss from this fungus. If the fungus inadvertently became established in New Zealand, we expect the impact of the fungus would be low. The low impact does not justify the cost of testing tissue cultures for this fungus or requiring them to stay in PEQ for longer. We also expect to see symptoms if it were to be present.

Other fungi
(Pestalotiopsis cruenta)

General requirements that apply to all tissue cultures manage the risks of water moulds and root rot fungi.

The water mould (Phytophthora palmivora) has had only one recorded detection from mangosteen (Zitko S. E. & Timmer, L. W., 1994). This water mould usually lives in soil and water but can sometimes live on leaves. Given the weak association with mangosteen and the very low likelihood of this pest being transferred to tissue cultures derived from new aerial plant material, we do not think this water mould is a risk in tissue culture (plants in vitro).

Red root rot fungus (Ganoderma nephelii) and brown root rot fungus (Pyrrhoderma noxium) live in roots and soil, and so they are not a risk on mangosteen tissue cultures that are derived from aerial plant parts.

This means that we do not need to take any further actions to manage risk from these pests while plants are in post-entry quarantine.

Water mould
(Phytophthora palmivora)

Red root rot fungus
(Ganoderma nephelii)

Brown root rot fungus
(Pyrrhoderma noxium)

• Level 2 PEQ for at least 6 months with three shoot flushes.
• Control on irrigation and drainage during quarantine.
• Aerial part of all bare-rooted whole plants need to be sprayed or dipped in 1% sodium hypochlorite for a minimum of 2 minutes on arrival at the quarantine greenhouse.
• Test during quarantine.
• General requirements that apply to all imported plants.

Rambutan plants could have a water mould that can spread through water. The chance of this is very small. We only found one report of this mould on rambutan plants in Thailand. This was a communication between the government of Thailand and the USA (THDOA 2004 in USDA 2007).

The water mould can be contained in Level 2 PEQ if irrigation water is collected and treated before it is released from the quarantine. This water mould could affect taro if it becomes established in New Zealand.

We were only able to find one record of it being found on taro so we expect the overall impacts would be low.

We are proposing growing season inspection should be sufficient to manage the risk of this water mould as we expect to see symptoms within 6 months of post-entry quarantine if it is present in rambutan plants.

Water mould
(Phytophthora botryosa)

Rambutan bare-rooted whole plants could have a powdery mildew that can spread through the air. This mildew also affects citrus. However, the likelihood of this mildew entering New Zealand on rambutan plants is low as the infection is mainly on and starts from young shoots/leaves.

Plants with visible symptoms of disease will not be exported to New Zealand. A higher level of post-entry quarantine is not justified despite the fungus being airborne. This is because plants are likely to express symptoms and be detected during regular inspections before the fungus starts releasing spores.

Surface sterilisation of the aerial parts of the plant will also further reduce the risk. We propose managing the risk of this mildew by inspecting plants for symptoms throughout the minimum 6-month quarantine. This is similar to how we manage the risk of this pest on citrus.

Powdery mildew of rambutan
(Erysiphe quercicola)

The Level 2 quarantine manage several other fungi.

These fungi can live internally in the plant (not on the surface). While we expect to see visible symptoms within 6 months in post-entry quarantine, it is possible that some plants could be infected without showing symptoms during quarantine. However, most of these are low-impact fungi, and the extra certainty we would gain from testing for them does not justify the cost of the test.

One fungus (Lasiodiplodia pseudotheobromae) is not a low-impact pest and also affects citrus, grapevines and avocado. Because this fungus has more serious impacts, the extra certainty we would gain from testing for this fungus justifies the cost. We propose bare-rooted bare-rooted whole plants to be tested for this fungus. This is similar how we manage the risk of this pest on avocado.

Other fungi

(Lasiodiplodia pseudotheobromae, Lasiodiplodia iraniensis, Lasiodiplodia hormozganensis)

Rambutan bare-rooted whole plants need at least 6 months in Level 2 post-entry quarantine to manage risk from these pests.

We are uncertain whether visible symptoms of all these fungi will develop in 3 months, and so we are proposing 6 months in post-entry quarantine. The plants are likely to develop visible symptoms within 6 months and these fungi will also be contained in Level 2 post-entry quarantine.

One fungus (Pestalotiopsis mangiferae) can live internally in other plant species, but we don’t have evidence that it lives internally in rambutan plants. There is a small possibility that we might not see visible symptoms in PEQ, but as it has an overall low impact, we do not think this justifies the cost of testing.

Thread blight fungus
(Corticium koleroga)

Brown root rot fungus
(Pyrrhoderma noxium)

White root rot fungus
(Rigidoporus microporus)

Other fungi
(Dolabra nephelii,

Pestalotiopsis cruenta,

Pestalotiopsis flagisetula,

Pestalotiopsis mangiferae

Pestlaotiopsis virgatula)

The general requirements for all nursery stock greatly reduce the risk of many pests that could come with the plants, including nematodes.

Insects

Mites

Nematodes

• Level 2 PEQ for at least 6 months with 3 shoot flushes.
• Test during quarantine
• Control on irrigation and drainage during quarantine.
• All leafless cuttings must be dipped in 1% sodium hypochlorite for a minimum of 2 minutes on arrival at the quarantine greenhouse.
• All general requirements.

Rambutan cuttings could have a water mould that can spread through water. We think the chance of this is very small, as we found only one report of this mould on rambutan plants in Thailand. This was a communication between the government of Thailand and USA (THDOA 2004 in USDA 2007).  

Although this mould it is not a high-impact pest, there is a small chance it could affect taro if it becomes established in New Zealand, based on one record of it infecting taro.  

P. botryosa has a low likelihood of being present in rambutan cuttings. We also think it would have low impacts on taro and rambutan. The water mould can be managed by inspecting the plants during their growing season while they are in Level 2 post-entry quarantine for 6 months, especially if there are additional measures to manage irrigation and drainage. This is because we expect to see symptoms within 6 months if it is present in the plants. 

Water mould (Phytophthora botryosa)

Rambutan cuttings need at least 6 months in Level 2 post-entry quarantine because several fungi are not managed by general requirements on their own.

Some of these fungi affect commercial crops such as citrus, avocado and grapevines. However, most of these fungi are likely to be detected during quarantine because the plants are likely to develop visible symptoms within 6 months.

While some of these fungi can be airborne, the likelihood that they will be present on a leafless semi-hardwood cutting is low, the likelihood will be further reduced by surface sterilisation on arrival at the PEQ.

However, one fungus is not a low-impact pest. It affects citrus, grapevines and avocado and can be present without showing symptoms. We propose cuttings to be tested for this fungus (Lasiodiplodia pseudotheobromae).

Thread blight fungus
(Corticium koleroga)

Powdery mildew of rambutan (Erysiphe quercicola)

Stem canker fungus
(Dolabra nepheliae)

Other fungi
(Lasiodiplodia pseudotheobromae, Lasiodiplodia iraniensis, Lasiodiplodia hormozganensis, Pestalotiopsis cruenta, Pestalotiopsis mangiferae, Pestlaotiopsis virgatula)

Fungi that cause root rot live on roots and as such are unlikely to be on cuttings. Cuttings might still have spores on their surfaces but sterilising the cuttings will likely kill off the spores and manage the risk.

White root rot fungus
(Rigidoporus microporus)

Brown root rot fungus
(Pyrrhoderma noxium)

• Tissue cultures derived from new aerial plant material.
• Level 2 PEQ for at least 3 months for plants derived from tissue cultures.
• 3 shoot flushes in PEQ for plants derived from tissue cultures.
• All general requirements.

The fungus can live in plants internally, but it is even less likely to be present in tissue culture than in whole plants or cuttings. We want to require tissue culture to only be derived from new aerial plant material as this will further reduce the likelihood of the fungus being present.

Inspecting the plants for this pest during growing season while they are in PEQ will give us confidence that plants do not have the fungus, particularly since there is already a low likelihood of the fungus being in tissue cultures. This likelihood is so low that minimum measures for tissue cultures will manage the risk. The extra certainty we get from testing does not justify the cost of testing.

Fungus (Lasiodiplodia pseudotheobromae)

The general requirements for tissue culture will manage several other fungi. These fungi show visible symptoms on plants and diseased plants are unlikely to be used to initiate tissue cultures. We are also proposing only new aerial plant material be used to initiate tissue cultures.

Thread blight fungus
(Corticium koleroga)

Stem canker fungus
(Dolabra nepheliae)

Powdery mildew of rambutan
(Erysiphe quercicola)

Water mould (Phytophthora botryosa)

Brown root rot fungus
(Pyrrhoderma noxium)

White root rot fungus
(Rigidosporus microporus)

Other fungi (Pestalotiopsis cruenta, Pestalotiopsis mangiferae, Pestlaotiopsis virgatula, Lasiodiplodia iraniensis, Lasiodiplodia hormozganensis)

Offshore factors

Export inspection and certification (phytosanitary certificate); transport; storage.

Onshore factors

Level 2 PEQ facility access for a minimum 6 months; MPI inspections and administration.

Pest-specific tests, including PCR and options for ELISA or plating where needed.

Expected overall cost
(compared to other plant imports that need Level 3B post-entry quarantine)

Low to moderate: Moderate cost per consignment if 3 shoot flushes don’t occur within the minimum 3 to 6 months in post-entry quarantine.

Uncertainties

Length of post-entry quarantine time because we are uncertain if 3 shoot flushes will occur in 3 to 6 months.

PEQ levels

Pest risks that can be managed during PEQ

Physical and structural requirements

Level 3B greenhouse

All insects and mites

Viruses, viroids, phytoplasmas

All bacteria and fungi

All soil/waterborne pests/vectors

Glass polycarbonate

No mesh/openings

Mechanically ventilated

HEPA filtration

Negative air pressure

Level 3A greenhouse

Some insects/vectors

Mechanically transmitted viruses or viroids, phytoplasmas

Some bacteria and fungi

Some soil/waterborne pests or vectors

Glass, polycarbonate/other rigid material

Fine stainless steel mesh (0.2 mm)

Heating/cooling

Plumbed-in hand basin

Level 2 greenhouse

Some insects/vectors

Some viruses, bacteria and fungi

Some soil/waterborne pests or vectors

Glass, polycarbonate, twin skin polyfilm

0.6-mm mesh

Anteroom with handwashing facilities

Level 1 open field

Graft-transmitted organisms

Possibly low-impact minor pathogens

Clearly delineated site

Minimum isolation requirements