OMAFA Summer Student Avery Johnson demonstrating plant washes on-farm.
In this week’s “how-to” video, we’ll explore using plant washes on-farm.
Plant washes are a simple but effective method to detect low levels of critical pests, such as Thrips parvispinus.
Once you’ve washed out your pests, we’ve also developed a quick “decision tree” to help you easily determine if you’re dealing with Thrips parvispinus or another thrips pest.
Keep reading to find the link to the video and additional resources.
- Methods of Detecting Thrips parvispinus
- Video Description
- You’ve Washed Out Some Thrips – Now What?
- Acknowledgements
Methods of Detecting Thrips parvispinus
Lab methods for plant washes can be quite involved, so we’ve simplified things for growers. Photo by OMAFA.
As early intervention is key to dealing with tricky pests such as Parvispinus, we’ve discussed possible ways to help detect this pest in the early stages of crop production in a previous post.
However, when populations are slow to build up, as in the first few weeks of propagation, we’ve discovered that regular detection methods such as sticky cards and plant taps just aren’t good enough.
Plant washes have long been recognized as the “gold standard” for detecting low levels of pests in greenhouse experiments or to get accurate counts of natural enemies (such as mites) on the crop.
We’ve adapted this method to be done easily on-farm, with supplies you can get from Amazon or the Dollar Store.
Washes can be done on propagative material (you’ll have to sacrifice some cuttings), or in later stages of growth, as shown in the video below.
Video Description
All videos were made by the Vineland Research and Innovation Centre, in collaboration with the Ontario Ministry of Agriculture, Food and Agribusiness (OMAFA) (NOTICE OUR NAME CHANGE!). These videos and are applicable to both greenhouse floriculture and vegetable crops.
Video Title: Plant washing method for sampling thrips and mites on farm
Production Date: May 2024
Description: Plant inspections and plant taps are not always effective sampling strategies depending on what pest species you are looking for. Plant washing is a more accurate way to detect low levels of highly damaging thrips and mites. This method can also be used regularly to help monitor pest or natural enemy pressure. This video outlines how to conduct plant washes on-farm using a few basic tools.
Disclaimer: the appearance of any products in these videos does not constitute endorsement by OMAFA or Vineland Research. Videos contain current information as of the initial release date. Some products or procedures that were not available or widely used at the time of filming were not included in these videos. Any products featured in the videos may currently be unavailable or discontinued.
You’ve Washed Out Some Thrips – Now What?
We’ve previously advocated for the use of our simple thrips key for growers for identifying thrips in your greenhouse (update coming soon!). Although we obviously think this is the bestest tool of all time, we recognize it has a lot of steps to get you to a final species identification. But sometimes you just need to know, IS IT PARVI OR NOT PARVI???
To answer this simple question, Ashely Summerfield (Vineland) and I developed a quick decision tree. We hope you like it!
Parvi-or-Not-decision-tree-printable-on-legal-sizeDownload
To use the decision tree, you’ll still need to see certain features on the thrips that can only be seen at around 40X magnification. (So a regular hand lens isn’t going to cut it!). This is usually done with a dissecting microscope. (Need to buy one? Check out our Guide to Buying Microscopes!).
If you’re not ready to invest in a microscope, you can also buy this really neat phone attachment for under $50 CDN! It’s not perfect, but if the specimens are dead, and you use the built-in light feature, the image quality is often good enough to be able to see key features, like hairs on the pronotum (see the middle picture, below).
This hand lens definitely not actually 200X magnification (despite its description). It’s more like 35-40X, in my opinion. But if you compare it with the photo taken with an actual microscope (far right, below), it definitely gets the job done, especially compared to a regular 20x hand lens (left image).
24x standard hand lens with through iPhone camera
Phone “microscope” hand lens through iPhone camera
Dissecting scope at 45x through a Samsung phone camera
Note: If the link above doesn’t work, simply type in “200x phone microscope” into Amazon.ca’s search bar. We also plan to have a more detailed blog post about microscope and hand lens options in the near future!
Acknowledgements
These videos were funded by the Ontario Agri-Food Innovation Alliance (previously the OMAFRA-U of G Partnership). This is a collaboration between the Ontario Ministry of Agriculture, Food & Agribusiness and the University of Guelph to advance research and innovation that contributes to the success of the province’s agri-food sector and promotes rural economic development. Videos were made as part of the KTT Funding Program stream.
Funding was also received by the Canadian Greenhouse Conference.
We sincerely thank those that contributed to the making of these videos, including: Dr. Rose Buitenhuis (Vineland), Jesse DeHaan (Vineland), Dr. Sarah Jandricic (OMAFA), Laxmi Khadka (Vineland), Cara McCreary (OMAFA), Caitlin MacDonald (Vineland), Ashley Summerfield (Vineland) and Taro Saito (Vineland).