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Myrtle rust 

MRComposite4Myrtle rust (Austropuccinia psidii) is a serious fungal disease that affects plants in the myrtle family (family Myrtaceae). The myrtle family consists of trees and shrubs originating in both tropical and temperate regions. Well-known members of the myrtle family include eucalypts, feijoas, guavas, bottlebrushes (Callistemon spp.) and New Zealand native species such as pōhutukawa, rata, mānuka and kānuka.

Symptoms

Myrtle rust attacks young, soft, actively growing leaves, shoot tips and young stems. Initial symptoms are powdery, bright yellow or orange-yellow pustules on leaves, tips and stems. The developing lesions may cause a deformation of the leaves and shoots, and twig dieback if the infection is severe. Symptoms also sometimes affect flowers and fruit. Infection of highly susceptible plants may result in plant death.

What can I do?

First things first - don't touch it! Why shouldn't you touch it? Because Myrtle rust spores can be readily dispersed by wind or on clothing, equipment etc. Both modes of dispersal can transport spores very long distances. If you think you have seen it, take a photo and call MPI's Exotic Pest and Disease Hotline on 0800 80 99 66.

Impact

Myrtle rust has been identified as a threat to New Zealand. The impact of myrtle rust has been particularly severe in Australia where it affects over 200 plant species. New Zealand has a number of species in the myrtle family considered to be at risk, among them iconic natives such as pōhutukawa, ramarama, rata and mānuka, but also feijoa, plantation and amenity eucalypts and numerous ornamental plants. 

This fungus has continued to expand the recorded range of susceptible species as it has spread from country to country. It seems likely that myrtle rust will continue to find new susceptible species or even new susceptible genera, now it has reached New Zealand.

Distribution

This fungus is indigenous to Central and South America and the Caribbean. It also occurs in Florida. Myrtle rust was found in Hawaii in 2005, where it was initially found on ohia (Metrosideros polymorpha) a species closely related to pohutukawa and rata. It was later found on other hosts (all in the Myrtaceae family). It reached Australia in 2010, where it was initially detected on a property on the central coast of New South Wales. Since then it has spread across much of New South Wales, Queensland and Victoria. It has also been found in Tasmania and, most recently Kerikeri in Northland, in the New Zealand offshore island Raoul Island.

To learn more about myrtle rust, click here


Reference: Ministry for Primary Industries

Brown Marmorated Stink Bug

BMSB10Brown Marmorated Stink Bug (Halyomorpha halys) is an agricultural pest found in Asia, notably China, Japan, and Korea; it has aggressively invaded the US and could successfully establish in New Zealand.

This insect feeds on more than 300 hosts, primarily fruit trees and woody ornamentals but also field crops. Almost any crop can be at risk, including citrus; pipfruit; stonefruit; berries and grapes; asparagus; soybeans and maize; honeysuckle; maple; butterfly bush; cypress, hibiscus; and roses. 

Adults generally feed on mature and immature fruit, while nymphs feed on leaves and stems as well as fruit. It severely disfigures fruit and renders it unmarketable, which results in control costs and production losses. Brown marmorated stink bug (BMSB) damage to woody ornamentals and forest trees has been reported as cosmetic only. 

BMSB is not a risk to human health but is a public nuisance. When disturbed or crushed it emits a characteristic, unpleasant and long-lasting odour. 

What does it look like?

Adults are approximately 1.7 cm long, with a distinctive brown “shield” shape with a white band around edges of the abdomen. The underside is white/tan, legs and antennae are brown with white banding.

Eggs are light green, barrel-shaped, and found in clusters of 20–30 eggs. These eggs are laid on the underside of leaves.

Young nymph stages are yellowish brown, mottled with black and red. Older nymph stages are darker, with the banding pattern on the legs and antennae beginning to appear.

How could it get here?

The adults naturally tend towards cracks/crevices to shelter from the environment in the winter months and may find their way into loaded containers for export. The insect has also spread through the transport of personal effects and housewares. It may also find its way into luggage and mail. Eggs, nymphs, and adults can be associated with a very wide range of plant material.

MPI has a number of measures in place to reduce the risk of exotic pests being introduced including requirements for importers and screening at the border. However, there is no such thing as zero risk and it is possible the insect could hitch-hike its way into the country undetected.

What can I do?

Horticulturalists and home gardeners: Report any suspect finds to MPI's Exotic Pest and Disease Hotline on 0800 80 99 66. If possible photograph and/or collect samples. Travellers and those receiving mail from overseas: Please make sure you open luggage and mail from overseas in an enclosed space to contain any hitch-hiking pests.

Report anything you find to MPI's Exotic Pest and Disease Hotline on 0800 80 99 66. If possible photograph and/or collect samples.

For more information, click here.

Reference: Ministry for Primary Industries 

Mycoplasma bovis

pexels photo 66403Mycoplasma bovis is a bacterium that causes illness in cattle, including udder infection (mastitis), abortion, pneumonia, and arthritis. It does not infect humans and presents no food safety risk. There is no concern about consuming milk and milk products from affected cattle.

Mycoplasma bovis is mainly spread by direct contact between infected animals and on equipment that has been used on infected animals, e.g. used for milking, artificial insemination, veterinary procedures. It spreads through bodily fluids including mucus and vaginal secretions. It is not thought to be transmitted in urine or faeces. It is not windborne or spread in rivers and streams. It is a relatively slow-moving disease

Symptoms

In dairy and beef cows:

  • untreatable mastitis;
  • abortions, swollen joints, and lameness (severe arthritis/synovitis) in all ages of cattle.

In calves:

  • severe pneumonia, starting as a hacking cough;
  • ear infections, the first sign typically being one droopy ear, progressing to ear discharges and in some cases a head tilt; and
  • conjunctivitis.
Distribution

Mycoplasma bovis is present in most countries in the world and is not listed by the OIE. New Zealand is special in having been free of this disease until now; this has saved our farmers' production costs, disease costs, and farm management costs that other countries have faced for decades.

What can I do?

Make sure you understand how Mycoplasma bovis spreads and what measures you can take to reduce its spread. For more information, click here

If you have any concerns about your animals, contact your vet as soon as possible for advice or call MPI on 0800 80 99 66.