A major cross-industry project is tackling damaging crop pests with a coordinated national approach involving surveillance, diagnostics, forecasting and engagement.
Ken Young, GRDC Senior Manager Biosecurity and Regulation, says iMapPESTS aims to put actionable information into the hands of Australias primary producers to enhance on-farm pest management decision-making.
Once established, the system aims to enhance pest management decision-making by providing timely information on current pest and disease abundance and spread, and provide early detection of exotic incursions, he says.
This information could guide the direction or intensity of scouting efforts and pest management actions.
The system is designed to be able to be used in a coordinated response to biosecurity efforts during exotic pest and disease incursions, including use in delimiting surveys and proof-of-freedom claims.
GRDC has joined with Australias plant-focused research and development organisations in the five-year Rural R&D for Profit project, iMapPESTS.
Once established, the system aims to enhance pest management decision-making by providing timely information on current pest and disease abundance and spread, and provide early detection of exotic incursions
From 2017-2022 iMapPESTS will lay the foundations for a national surveillance system that can rapidly monitor and report the presence of airborne pests and diseases affecting major plant based agricultural sectors across the country, including grains, cotton, sugar, horticulture, wine and forestry.
- Custom designed and built surveillance units (Sentinels) with specialised trapping equipment and technology deployed at various locations across regional Australia to monitor the presence of high-priority pests and diseases.
- Samples captured by the Sentinels analysed using morphological identification and advanced molecular diagnostic tools to rapidly detect and quantify high-priority pests and diseases.
- Surveillance data uploaded to the cloudbased platform, AUSPestCheck, and used to develop a forecasting tool for predicting abundance and spread of high-priority pests and diseases. These data will be summarised in simple tailored information products (e.g. reports and alerts) for growers and agronomists.
- Key stakeholders will be engaged and supported on use of the systems information through a range of communication and engagement activities, including workshops and events.
iMapPESTS aims to validate a proof-of-concept surveillance system that can rapidly monitor and report the presence of high-priority pests and diseases.
Tracking Russian wheat aphid
In other news, entomologists are hot on the heels of Russian wheat aphid as it pushes northwards, with new surveys showing where autumn incursions are endangering spring plantings.
Jess Lye, cesar Team Leader Extension and Communication, says the presence of RWA in an area does not automatically mean it will cause damage to crops as the pest must infest cereals in early autumn in order to develop into damaging population levels during spring booting and flowering.
Sampling in the spring and late summer of 2018 has enhanced industry understanding of the conditions that support survival of leading into autumn sowing, Dr Lye says.
Recent observations support international research findings that indicate mature crops (GS 40 or higher) are less attractive and are less likely to be invaded by RWA in spring.
Field observations and experiments over the past three seasons indicate that RWA abundance and development on crops is much higher in low rainfall zones (under 400 millimetres per year) and on drought stressed crops. However, this work is ongoing.
RWA is still a very new pest to Australia and researchers are continuing to learn about its biology as the current investment progresses.
During spring sampling RWA was found on a variety of non-crop grasses, with barley grass appearing to be the preferred host, followed closely by brome grasses (including prairie grass). Symptoms (curled and striped leaves and trapped heads) were rarely observed in non-crop grasses.
Looking for symptoms is therefore not a good strategy for monitoring RWA presence in weeds.
Volunteer cereals and weedy grasses found within next seasons cereal paddocks should be controlled at least two to three weeks prior to sowing. This will aid in reducing local numbers of the aphid pre-production.
The GRDC investment, Russian wheat aphid risk assessment and regional thresholds is investigating regional risk and management tactics for RWA, including the surveys conducted by South Australian Research and Development Institute (SARDI) and cesar.
The team reports RWA is present in a large, and still expanding, area covering all cereal growing regions of South Australia, Victoria, Tasmania and most of New South Wales.
RWA has recently been detected at Coonabarabran and the Liverpool Plains, NSW, which represent a northerly extension of the current range.
The effect of climatic conditions
This investment is assessing the ability of Russian wheat aphid to survive under different climate conditions.
While one season of data has been collected to date and researchers can give limited advice, here is what they say:
- Hot and dry summer conditions will reduce over-summering populations of the aphid, with RWA likely to persist where there is available moisture and green material (from rainfall or irrigation).
- The long-term climatic outlook for the south eastern region from December 2018 to January 2019 expects higher than normal temperatures. This is unfavourable for RWA survival.
- The long-term climatic outlook for the south eastern region from December 2018 to January 2019 expects average rainfall. This will have a neutral effect on RWA survival. Localised summer rainfall events resulting in germination of weeds like barley grass can, however, change this situation by providing further refuges.
More pertinent information about environmental influences is likely to be gained at crop establishment, particularly about area-wide aphid abundance and flight timing.
Significant early infestation of a crop will only occur through a combination of abundant green bridge and good flight conditions that aid RWA migration to cereal paddocks during the seedling stage in early autumn. Good flight conditions are calm, warm days over 20°C. Over the 2018 season these conditions were not met in southern Australia.
Risk of yearly seed treatment
Registered neonicotinoid insecticide seed treatments are very effective to avoid autumn infestation of crops if Russian wheat aphid are migrating.
However, over the 2018 season migrations into crops did not occur in most areas where RWA is present, most likely due to unfavourable conditions for aphid survival over summer, and unfavourable flight conditions.
Using neonicotinoid seed treatments (Imidacloprid, Clothianidin, Thiamethoxam) on each crop and each rotation can support the evolution of resistance in RWA, which we are seeing in other notorious crop pests, such as the Green Peach Aphid, which has recently acquired moderate resistance to neonicotinoids in Australia.
Growers are urged to use neonicotinoid seed treatments judiciously, according to the regional risk, and using the FITE (Find, Identify, Threshold, Enact) approach.
RWA is easy to detect in autumn and winter before yield is impacted.
If RWA is present in potentially damaging numbers it can be controlled efficiently by insecticide sprays around growth-stage 32-40, eliminating the aphids before there is a risk of yield loss.
The overseas threshold at GS 30 is more than 10 per cent of tillers infested. See the RWA Tips and Tactics guide for further information.
Research establishes local thresholds
Australian thresholds for Russian wheat aphid (RWA) will replace the overseas thresholds used to inform control since 2016, under GRDC-funded research.
Researchers are investigating the impact of RWA on a range of cereals and under different regional conditions using Australian field trials until June 2020.
SARDI and cesar will assess the regional pressure of RWA and its impact on yield, aiming to provide risk estimates and management options for growers.
The research will answer:
- What is the regional risk posed by RWA?
- What are the economic thresholds that will guide growers in effective management of RWA?
- What role do green bridges play in supporting RWA populations between cereal cropping periods?
This investment includes on-the-ground assessment of RWA impact at trial sites set up in all Australian cereal production areas where it has been detected. Researchers will also assess control by beneficial insects.
Findings will more guidelines for RWA management to be developed.
Planning tool advances on-farm biosecurity
On paper, online or by mobile device, preparing biosecurity action plans became both easier and more essential for grain growers in 2018.
A new planning tool was developed to help grain growers identify and address their biosecurity risks, with legislation in Queensland and New South Wales in particular making growers responsible for understanding and acting on the risks of their day-to-day activities.
The Farm Biosecurity Action Planner has been developed as a paper-based, online or mobile app through the Farm Biosecurity Program, a joint initiative of Plant Health Australia (PHA) and Animal Health Australia (AHA).
Growers can print their own copy and fill in the details by hand or record the actions they will take in the documents electronic fields with a computer.
The information in the planner has also been included in a free app called Farm Biosecurity, available from the App Store and GooglePlay.