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Potatoes NZ is undertaking a range of research projects to help growers deal with the tomato / potato psyllid, Liberibacter, and Phytoplasma complex. This includes a series of workshops, the establishment of a psyllid working party, and a major Sustainable Farming Fund project. Upcoming work includes the launch of a regular psyllid update for the industry and workshops in 2010.
The Psyllid / Liberibacter / Phytoplasma complex
The tomato / potato psyllid, Liberibacter, and Phytoplasma complex poses a significant threat to the New Zealand potato industry – the psyllid has spread quickly across much of New Zealand and some crops have been severely affected as a result. Potatoes New Zealand is undertaking research, running workshops, and distributing resources to assist grpwers to monitor and control the psyllid, and the diseases it is thought to spread.
The psyllid was originally found in 2006 on tomatoes and potatoes in the Auckland and Waikato regions. Adults look like tiny cicadas, 2 - 3 mm long. It is a serious pest of potatoes and tomatoes, as well as capsicum and other solanaceous crops, and is difficult to control. In 2007 the psyllid spread south and was also found in Nelson. In 2008 it was found in outdoor tomato crops in the Hawkes Bay and Gisborne. Its ultimate range may be limited by winter temperatures.
The psyllid is a vector for Liberibacter, a disease which causes zebra chip in potato tubers as well as yellowing and plant death. The Phytoplasma is a bacteria-like organism associated with disease symptoms on potatoes. The relationship between the psyllid, Phytoplasma, and disease symptoms has not yet been confirmed.
A range of resources on the tomato / potato psyllid, Liberibacter, and Phytoplasma complex are presented below.
Monitoring
Regular monitoring for the tomato / potato psyllid is essential for effective control. Two types of monitoring can be carried out. Placement of yellow sticky traps indicate when adults are prevalent in the area, but not enough is yet known to establish control thresholds. The other options is inspecting plants (particularly the lower 1/3 of stems and leaves) which gives valuable information on the numbers and life stages present in the crop, and can be used to direct to types of control products to be used.
It is also useful to monitor (or preferably remove) alternative hosts which include the common weeds dandelion, amaranth, convolulus, jimson weed, mallow, and black nightshade. Ornamental solanaceous plants are also potential hosts, and so is the native plant poroporo.
Through the Sustainable Psyllid Management MAF SFF project Potatoes New Zealand are supporting national monitoring of psyllid numbers in key regions. It has come to our attention that growers wish to have monitoring done on their own properties and / or identification of suspected infested crops. Unfortunately Plant and Food Research, while they wish to support industry in every way possible, do not have sufficient staff to provide this service, mainly due to heavy workloads associated with industry funded research projects on the psyllid. In recognition of the skill level required to identify psyllids and differentiate between native and tomato / potato psyllid, Potatoes New Zealand have identified individuals that can provide this service - these are Tim Herman (Hawkes Bay 027 490 3359) and John Thompson (Auckland 027493 0199).
We are trying to identify someone to service the South Island. Please note that should you wish to employ the services of these individuals it will be at your own cost – Potatoes New Zealand are merely providing this recommendation to individuals requiring their own monitoring.
Psyllid monitoring is now being carried out at sites across New Zealand as part of the Sustainable Psyllid Management SFF project. This data, along with the latest information on psyllid monitoring, is presented below.
Control
The potato psyllid is a difficult pest to control, and when spraying thorough coverage of all parts of the plant is essential. The density of plant material late in the season can make it difficult to obtain good coverage and use of recommended water rates is considered to be essential. Growers are encouraged to follow all aspects of Good Agricultural Practice, especially the observance of pre-harvest intervals and following resistance management guidelines.
The following information provides some guidance on psyllid control strategies.
Archive
Psyllid & Liberibacter workshop March 2009
On 26 March 2009 a workshop was held in Christchurch to discuss the psyllid, zebra chip, Liberibacter, and the new phytoplasma. The proceedings of this workshop can be downloaded by clicking the links below.
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Psyllid News
Joe Munyaneza: American psyllid export Joe Munyaneza visited New Zealand in early March 2010. Click here to download his presentation.
Psyllid Newsletter: the first issue of the psyllid newsletter "Psyllid News" is now available. Click here to download it now.
MAF SFF tomato / potato psyllid research project: supported by the Sustainable Farming Fund, grower levies, and Plant & Food Research internal funding, a cross-industry team will direct researchers in the development of management systems for the tomato / potato psyllid . Project outputs include resources containing up-to-date information about the insect and associated bacterium, laboratory and field evaluation of control options (including conventional and soft insecticides and biological control agents), and a system for evaluating the disease status of planting material. This is a three year project.
Workshops: Five workshops were run across New Zealand in August / September 2009 with more than 250 people attending these. Presentations from these workshops can be downloaded from this web page.
Psyllid working party: a Potatoes NZ working party has been established to deal with the psyllid issue. The working party will be responsible for direct industry actions to assist growers, monitoring developments / impacts on industry, communicating research findings & information, adapting strategies to respond, and encouraging international collaboration.
Psyllid update: a quarterly psyllid update will be published from late 2009. This will be available to all growers and will include the latest research and information.
2010 updates & workshops: Potatoes NZ is planning in-depth workshops which will involve New Zealand and US scientists. The aim of these workshops is to bring the latest results of New Zealand and US research programmes to growers. These events will be well advertised ahead of time.
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