Tomato potato psyllid
The Tomato potato psyllid (TPP) is a tiny insect pest which attacks the Solanaceae family of plants including potato, tomato, eggplant, capsicum, chilli and tamarillo. It also attacks sweet potato and other plants in the Convolvulaceae family.
In February 2017, TPP was detected in a range of commercial and backyard crops across the Perth metropolitan area, in addition to a small number of detections north of the Perth metropolitan area and parts of the South-West.
The Western Australian Department of Primary Industries and Regional Development (DPIRD) is continuing efforts to manage and contain TPP following the National Management Group's (NMG) decision it cannot be eradicated.
NMG made the decision based on the recommendation provided by the Consultative Committee on Emergency Plant Pests (CCEPP). This technical group's role is to provide recommendations to NMG on whether or not it is technically feasible to eradicate the pest.
Following NMG’s decision, DPIRD (with assistance from CCEPP members - including industry) developed a comprehensive transition to management plan designed to limit and manage the impact of the tomato potato psyllid throughout Australia.
Transition to management plan
The national Transition to Management Plan will improve the capacity of the horticulture sector to manage TPP, and build confidence around the status of the bacterium Candidatus Liberibacter solanacearum (CLso) associated with TPP. There have been no detections of CLso in Australia to date.
Western Australia is leading the implementation of the plan, working with the national TPP coordinator and other states/territories.
The Transition to management plan includes the following major activities:
- targeted surveillance for TPP/CLso complex during spring 2017 and autumn 2018
- scientific research to improve understanding of TPP, its biology and options for control.
- management of TPP through the development of national and enterprise management plans
- market access and trade.
The Western Australian community has rallied to support spring surveillance efforts for TPP, with more than 1000 home gardeners taking part and 4000 sticky traps distributed across the surveillance area. The spring surveillance program is now complete.
A Quarantine Area Notice is in effect for the Perth metropolitan area and surrounds to help prevent the spread of TPP.
Western Australian commercial vegetable growers, the nursery industry and home gardeners are reminded of conditions on the movement of host plants.
For more information about the restricted area, including commercial treatment guidelines for movement of host plants and a map see the Department of Primary Industries and Regional Development website.
Identifying and reporting affected plants
Commercial and residential growers of host crops are advised to regularly check host crops for signs of TPP.
TPP can spread through the movement of tomato, capsicum, eggplant, tamarillo and other solanaceous plant material. It can also occur on other hosts, including the Convolvulaceae plant family - which includes sweet potato. It can also disperse through natural pathways such as flight and on the wind.
TPP is a significant production pest in other countries where it is present, which include the USA, Central America, New Zealand and Norfolk Island which is an external Australian territory.
What to look for
TPP (Bactericera cockerelli) is a tiny sap-sucking insect with three stages of development – egg, nymph and adult. All stages are very small (less than 3mm) but can be seen with the naked eye. Adults and nymphs cause injury to plants when feeding.
Adult TPP (3mm long) resemble small winged cicadas in appearance, but are the size of an aphid. The body is brownish and has white or yellowish markings on the thorax and a broad white band on the abdomen. Wings are transparent and held vertically over the body.
When present in a crop, noticeable signs of TPP include:
- Insects jumping from the foliage when disturbed. Adult psyllids are sometimes called jumping plant lice as they readily jump and fly when disturbed.
- Severe wilting of plants occurs when there are large numbers of psyllids feeding.
- Yellowing of leaf margins and upward curling of the leaves.
- White sugar-like granules that are excreted by adults and nymphs. These granules coat the plant leaves and stems, and can lead to the development of sooty mould.
- Honeydew and psyllid sugar make the plants sticky and they often appear dirty.
- Shortening of stem internodes occurs.
The death of the stem is similar to other potato and tomato disorders.A number of pre-harvest control options are available to assist commercial growers with the management of TPP. Emergency permits were made available during the initial TPP response phase for use in host crops and nursery stock.
Permits are available to download from the Department of Primary Industries and Regional Development website.
About Candidatus Liberibacter solanacearum
TPP is a known vector of (can carry) the bacterium (Candidatus Liberibacter solanacearum or CLso) which causes Zebra chip disease in potatoes. This bacterium is also exotic to Australia and poses a threat to important horticultural crops such as potatoes, capsicum, chilli, tomatoes, eggplant and tamarillo.
There has been no detection of CLso to date.
Despite having no confirmed detections, growers should always check their plants for signs of disease.
What to look for
Zebra chip disease results in reduced crop yield and crop health, stem death, yellowing of leaf tissue, and misshapen tubers.
Symptoms of the Candidatus Liberibacter solanacearumbacterium on potatoes, tomatoes, capsicum and chilli may look similar to other plant conditions, so growers are urged to be vigilant for the following symptoms:
- In tomatoes, plants may become stunted or abnormally elongated. Leaf curling and yellowing occurs on the foliage. The fruit develops unevenly. Tomatoes may be misshapen or no fruit is produced or there is an over-production of small, non-commercial grade fruit. Symptoms vary in severity between cultivars.
- In capsicums and chillies, parts of the plant may die back. In foliage, leaves become misshapen, pale green or yellow with spiky tips and leaf stalks appear stunted. Flowers may drop prematurely. Symptoms vary in severity between cultivars.
- Symptoms of zebra chip in potatoes include the plant having shortened internodes and aerial tubers may develop in the leaf nodes. Potato tops are likely to be smaller than normal. The foliage turns yellow and may have a burnt or purplish appearance.
Stems may die completely but regrowth from the base may occur. Tubers from affected plants may have small stalked tubers protruding from the main tuber, called ‘chaining’, and when cut may show internal browning of the vascular ring or brownish streaks along the medullary rays.
Neither the psyllid or the bacterium pose a risk to human health.
Report your detection
This is a significant pest that needs to be contained and managed so it is important growers report any detections. If you think TPP or the bacterium that causes Zebra chip disease may be present in your plants, you must report this to the Exotic Plant Pest Hotline on 1800 084 881. Alternatively, you can use the DPIRD MyPestGuide reporting app.
Detections outside of Western Australia can also be reported to the Exotic Plant Pest Hotline on 1800 084 881. This number will put you in contact with your state or territory department of agriculture or primary industries.
Interstate movement restrictions
Some states apply movement restrictions to prevent the spread of pests and diseases. Be sure to check the Australian Interstate Quarantine website before moving any fruit, plants or plant products over state borders.