ipm principles and monitoring - ausveg · 2021. 5. 9. · the serpentine leafminer (slm: liriomyza...

The serpentine leafminer (SLM: Liriomyza huidobrensis)

IPM principles and monitoring

Dr. Elia Pirtle (Cesar Australia)

epirtle@cesaraustralia.com

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