Embed Size (px)
Citation preview
The serpentine leafminer (SLM: Liriomyza huidobrensis)
IPM principles and monitoring
Dr. Elia Pirtle (Cesar Australia)
Jan 28, 2021
• L. huidobrensiscaused 70% yield losses in potatoes in Indonesia in 1995…
Why such large losses?Image: Chirinos et al 2017
Above: Closterocerus nr trifasciatus, photos by Dr. Ryan Perry, University of California Riverside
• Understand role of parasitoids: know the signs of parasitism; understand the role of reservoirs of parasitoids (i.e. non pest flies).
• Monitor pest activity: follow economic thresholds to reduce sprays and allow parasitoid populations to build.
• Avoid broad-spectrum insecticides: do not target leafminer flies with inappropriate chemicals; consider effect of chemicals that target other pests
Foundations of IPM approaches overseas
Management of exotic leafminers
What will IPM look like on my farm?
Parasitoid wasps of leafminer
• Mortality results from parasitism, or by stinging and feeding by adult wasps.
• Unassisted field mortality rates can reach as high as 80%.
• Most of these wasps are very generalist (attacking many leafminer species)
Management of exotic leafminers
These wasps are very small (~1 mm) and pose
no threat to humans!
Hemiptarsenus varicornis on top of a 10 mm diameter thumb tack (tack image: Wikimedia commons; wasp
images: Elia Pirtle, cesar Pty Ltd)
Management of exotic leafminers
Hemiptarsenus varicornis. Image: Elia
Pirtle, cesar Pty Ltd
Diglyphus isaea. Image: Elia Pirtle,
cesar Pty Ltd
Opius spp. Image: Elia Pirtle, cesar Pty Ltd
?
Parasitoids in Australia
• Australia has many parasitoids which attack Liriomyza and other agromyzids
• Scientific papers report at least 50 species of beneficial wasps that might attack exotic Liriomyza are found in Australia
• This includes three of the most important overseas species
• Our sampling has found they are already providing important control of vegetable leafminer in the Torres Strait
It will be important to start looking for signs of parasitism in SLM in NSW and QLD!
Hemiptarsenus varicornis. Image: Elia
Pirtle, cesar Pty Ltd
Diglyphus isaea. Image: Elia Pirtle,
cesar Pty Ltd
Opius spp. Image: Elia Pirtle, cesar Pty Ltd
Below: Parasitoids of L. sativae in QLD, photos by Dr. Ryan Perry, University of California Riverside
No need for imports, just protect what we
have!
Management of exotic leafminers
• Understand role of parasitoids: know the signs of parasitism; understand the role of reservoirs of parasitoids (i.e. non pest flies).
• Monitor pest activity: follow economic thresholds to reduce sprays and allow parasitoid populations to build.
• Avoid broad-spectrum insecticides: do not target leafminer flies with inappropriate chemicals; consider effect of chemicals that target other pests
Foundations of IPM approaches overseas
Management of exotic leafminers
What will IPM look like on my farm?
Chirinos et al 2017
Management of exotic leafminers
Monitoring for leafminer and parasitoid activity
• Presence of leaf mines does not mean you need to intervene!
• Cheaply and easily assess leafminer activity by monitoring for pupae or adults via traps!
• Thresholds/monitoring techniques must be developed for Australia next
Chirinos et al 2017
Can you see signs of parasitism?
• Already seeing many signs in QLD samples!
Management of exotic leafminers idiobionts
koinobionts
Surveying for exotic leafminers
What will be the signs if SLM reaches my area?
• Early detection can avoid accidental disruption of wasps, creating an even
bigger problem
• Your reports will help us build and validate better management tools!
And why should I be looking…
When should I be looking?
Where should I be looking?
What should I look for?
Surveying for exotic leafminers
• Leaf mines are long lasting
• Flies are tiny, transient and short lived
• Traps are not feasible for early detectionActual size of adult
Targeting surveillance: What, when and where?
What should I look for?
Where should I be looking?
Surveying for exotic leafminers1. Targeted surveillance
When should I be looking?
• In the highest risk season, when high pest growth potential overlaps with crop growth (especially young crops)
Establishment risk
Targeting surveillance: What, when and where?
When should I be looking?
What should I look for?
Where should I be looking?
Surveying for exotic leafminers1. Targeted surveillance
• A high risk crop
Targeting surveillance: What, when and where?
• A high risk crop
• A high risk part of the paddock
• Based on spread pathways
• Near to transport routes and unloading areas
• The ‘incoming wind side’ of paddock edges
When should I be looking?
What should I look for?
Where should I be looking?
Surveying for exotic leafminers1. Targeted surveillance
wind
Targeting surveillance: What, when and where?
2. Survey guidelines
While surveying
• Scan: Scan upper surfaces of leaves as you walk, looking for signs of stippling or mining.
• Snap: Take a photo of any suspicious damage and record a GPS point.
• Collect: Take a sample of the damage
• Call: Immediately report to the Exotic Plant Pest Hotline on 1800 084 881.
Surveying for exotic leafminers
4. Call
Tips for conducting surveys
No!
• There are many other leafminer in Australia
• So what do we do…?
• Call anyway!
• Keep a sample!
Surveying for exotic leafminers
Allows for DNA testing!
Can I distinguish symptoms from
other pests?
• Understand role of parasitoids: know the signs of parasitism; understand the role of reservoirs of parasitoids (i.e. non pest flies).
• Monitor pest activity: follow economic thresholds to reduce sprays and allow parasitoid populations to build.
• Avoid broad-spectrum insecticides: do not target leafminer flies with inappropriate chemicals; consider effect of chemicals that target other pests
Foundations of IPM approaches overseas
Management of exotic leafminers
What will IPM look like on my farm?
Project MT16004
Thanks to our partners!
- Thursday Island and Bamaga NAQS- Torres Strait Regional Authority- Kaurareg Native Title (Aboriginal) Corporation- Torres Shire Council- NPA Regional Council- Apudthama Land Trust - Seisia Enterprises- Greenlife Industry Australia- Queensland Department of Agriculture and
Fisheries- Project partners and steering committee
All images unless otherwise noted: Dr. Elia Pirtle
