Plant producers are exposed to significant and continual pest and disease threats
Myrtle rust was first discovered in mainland New Zealand in 2017 on a pohutukawa seedling in a Kerikeri plant nursery. It has now been found across the North Island and in upper areas of the South Island.
Why we need Plant Pass
Nurseries are havens for pest and disease establishment. They are usually home to many plant species in a vulnerable, juvenile state growing in moist, warm conditions: an ideal pest incubator.
Therefore it is likely new plant pests will be first found in a nursery. Diseases and pests can then spread rapidly through the plant production supply chain as it is quick, efficient and nationwide.
New Zealand has experienced an increasing number of pest incursions over the last 50 years as international trade and travel have grown. Climate change is also increasing pest and disease risk.
Cinnamon fungus (Phytophthora cinnamomi), the plant parasite Pythium and the Fusarium fungus are ubiquitous; kauri dieback and myrtle rust continue to spread; and the red tomato spider mite, fall armyworm and invasive ants are of growing concern.
New Zealand plant producers manage these and other pests, daily.
Taking a proactive approach to biosecurity in the nursery is not only good for business but helps protect Aotearoa’s economy, unique natural environment and way of life.
Local threats to plant nurseries that Plant Pass can help manage
Fall Army Worm
The fall armyworm (Spodoptera frugiperda) is not a worm but a highly invasive moth that threatens plants in its larvae stage.
The larvae may do the damage, but the adult moths ensure the rapid spread of the pest. If pushed by winds, moths can fly up to 100km a day.
It arrived in New Zealand around February 2022, likely from Australia, and is now established in Auckland and Northland. It can survive on a range of plant species across 76 plant families.
Early detection and strong surveillance are the best defences against the fall armyworm. The Plant Pass core standard helps ensure this type of surveillance is part of a nursery’s biosecurity systems.
Tomato Red Spider Mite
The tomato red spider mite (Tetranychus evansi) feeds on a wide range of plants in the Solanaceae family.
In large groups, they can mummify plants, wrapping them up in silk webbing, and will feed on the plant until it dies. Known hosts include tomatoes, potatoes, kumara, eggplants, beans, ornamental plants such as roses and orchids and weeds such as shepherd's purse, cleavers, and fat hen.
It was discovered in Auckland in late May 2020. Growers can put biosecurity measures in place to reduce the chances of the mite getting into their plants.
Pepino Mosaic Virus
The pepino mosaic virus (PepMV) can cause pepino mosaic disease in tomatoes and some other solanaceous plants including potatoes and eggplants.
PepMV is spread on seed, stalks, and leaves and through plant to plant contact and propagation. It is also transmitted very easily on contaminated tools, hands and clothing. Bumblebees used as pollinators are also known to spread the disease.
It was detected in tomato plants at four Auckland commercial tomato growing greenhouse facilities in April and May 2021. Commercial growers are advised to closely monitor their crops for signs of the virus.
Granulate Ambrosia Beetle
The granulate ambrosia beetle (Xylosandrus crassiusculus) can damage a wide range of broadleaf trees, including horticultural species. It can also spread damaging fungi.
It has been recorded on more than 100 species in over 40 plant families. It will attack common fruit trees such as avocado, plum, peach, persimmon, and pear. It is known to attack common tree species such as oak, eucalyptus and magnolia.
The beetle was detected in Auckland in February 2019. It was found in native and exotic species in seven areas within Auckland.
Potato Spindle Tuber Viroid
The potato spindle tuber viroid (PSTVd) is a pathogen that causes disease and potential loss of production, mainly in potatoes, tomatoes, pepinos, and capsicum. It can also infect some greenlife plants, including dahlias, chrysanthemums, and petunias.
PSTVd is highly contagious and spread via seeds for planting or nursery stock.
The viroid has been found twice before in New Zealand in glasshouse tomatoes and capsicum, and in Cape gooseberry at a commercial operation in the Tasman district.
Myrtle Rust
Myrtle rust is a serious fungal disease that affects plants in the myrtle family. Some of our most iconic native plants are vulnerable to myrtle rust, including pōhutukawa, mānuka, rātā, swamp maire and ramarama. Some exotic species can also get the disease, such as bottlebrush and lilly pily.
Myrte rust was first found on a pōhutukawa seedling in a Kerikeri nursery in 2017. It has now been found across the North Island and in the upper half of the South Island.
Plant Pass includes a specific module on myrtle rust to help nurseries that grow myrtaceae species manage the disease and control spread.
Lilly Pilly Beetle
Adult Lilly pilly beetles and larvae (Paropsides calypso) feed on leaves of Syzygium, a genus of flowering trees and shrubs in the myrtle family (Myrtaceae), including popular hedging plants commonly known as lilly pilly. The beetles can completely strip the foliage of a plant.
Native to Australia, the beetles were first discovered in Helensville, Auckland, in early 2023. They are now believed to be well-established in the area.
Biosecurity New Zealand put out a fact sheet in January 2024 about the pest and how to detect its damage to plants.
Western Drywood Termite
The western drywood termite (Incisitermes minor) is a wood boring insect. It can attack dry wood in trees and plants and man-made wooden structures like boats, furniture, and other items.
They are not known to be currently present in New Zealand but have been found in vessels in the past which have come here from North America.
Biosecurity New Zealand is interested in any further sightings of this insect.