• Home
  • About
    • History
  • Grape Varieties
    • Petite Pearl Grape
    • Crimson Pearl Grape
    • Verona Grape
    • T.P. 1-1-12 Grape
    • T.P. 2-3-51 Grape
  • Purchase Vines
  • Future Vines
  • Blog
  • Contact
Plocher Vines
  • Home
  • About
    • History
  • Grape Varieties
    • Petite Pearl Grape
    • Crimson Pearl Grape
    • Verona Grape
    • T.P. 1-1-12 Grape
    • T.P. 2-3-51 Grape
  • Purchase Vines
  • Future Vines
  • Blog
  • Contact

Thoughts, Ideas, Etc

Forced to Choose

12/14/2021

 
Forced choice feeding environment used to compare relative attractiveness of two grape seedlings to feeding Japanese Beetles.
Japanese Beetles feeding on grape leaves.
​The 2018 season will forever be etched in my memory for its epic hatch of Japanese Beetles. Hundreds of thousands of them. I sprayed every week to kill them off.  By the next week, a whole new generation had emerged from the soil and moved into the vineyard. 
 
I got quite familiar with certain vines that seemed to be of lesser interest to the beetles.
There were some obvious ones, like ES 6-16-30 and T.P. 2-3-51, that the beetles were not attracted to because of their tough, corrugated leaves. But there were a few vines in the seedling blocks with thinner, uncorregated leaves that also seemed somewhat unattractive to the beetles compared to their neighbor seedlings.
 
One way to test the relative unattractiveness of these seedling vines was to set up a forced choice feeding environment for the beetles. I put a fixed number of beetles into a fine mesh containment bag that contained one growing shoot from a highly attractive seedling vine and one growing shoot from a neighboring, relatively unattractive vine.  If the beetles wanted to eat, they could choose either seedling or both.
 
At the end of the trial, each of the leaves in the study was photographed for later analysis of leaf damage.  I have not had time to finish the analysis of the photos, but hope to get to it this winter.
 
There may be some genetic basis for the unattractiveness. All four of the seedlings that showed some level of unattractiveness to Japanese Beetles are from the same cross and, genetically, one-fourth Vitis palmata.  My vine of Vitis palmata grows outdoors during the summer in a big pot. The beetles do not bother it, even though it is surrounded by potted vinifera vines which are highly attractive to them.

Low Cost 3D Imaging Technology for Measuring Grapevine Canopy Density

12/1/2021

 
Three images of grapevine canopy gaps. One, the original depth camera image. Two. A binary inversion of image to more clearly highlight canopy gaps. Three. Gaps depicted in colors to show major and minor gaps.
Canopy gap detection. Left: Original canopy image constructed from ten images. Middle: Binary inversion to clearly isolate 'blobs' where the Kinect IR laser beam passes through the leaf canopy and does not reflect back. Right: Gaps colored to overlay the original image, showing both major (blue) and minor (orange) gaps.

​Measures of vine canopy density all have the goal of evaluating light penetration into the leaves and fruiting zone.  Light that fosters growth and fruit maturation. Laser beams are a perfect analogue to natural light. Like natural light, some laser beams pass freely through openings along their path through the grapevine canopy, while others are blocked by leaves.

​I have always thought that one of Richard Smart’s most creative measures of canopy density and balance was “canopy gaps”.  It is, in fact, a measure of how open the leaf canopy is to light penetration. If you look at a VSP canopy from the side, the “gaps” are the places where light can pass through from one side of the vine to the other, unimpeded by leaves or fruit.  Or think of it as the spaces where you can see through the leaf canopy. If you can see through 30% of the leaf canopy, the vine gets a high score for being in balance. For years, I have eye-balled these canopy gaps in my vines. But I never had any idea how accurate my observations were.

Using a MS Kinect LIDAR device (cost $149) and several image processing steps, Chuck Hisamoto and Kale Hedburg from Aster Labs LLC, and I built a system that provides almost a perfect measure of gaps in the grapevine canopy. Much more accurate than what the human eye can estimate or even what can be estimated by the tedious use of manual point quandrant methods. And it does it almost instantly.

We also have conceived a method for automatically measuring the number of leaf layers in the canopy, another key measure of canopy density from Richard Smart. It uses the same low cost consumer LIDAR technology. We are looking for funding or investment to further pursue the implementation of that technology.

Temperature Variation in the Leaf Canopy

11/19/2021

 
Image of grapevine canopy with 1) a visual spectrum camera and 2) an infrared camera. The infrared photo shows the temperature variation on leaves and clusters in both sunny and shaded portions of the leaf canopy.
This is the same subject, photographed with visual spectrum camera on the left and then with infrared camera on the right.
I have always wondered about how much the temperature varies throughout the vine’s canopy, from shady areas to sunny areas. I have also wondered about how grape clusters, with their dark skins and thermal mass, accumulate heat during the day and dissipate heat at night, relative to the leaves. Thermal imaging is one way to paint a picture of temperature variations in the canopy. Thermal imagers have become consumer products. For less than $200, you can buy a FLIR One thermal imager that snaps into an iPhone and runs from an iPhone app.

The two images above give you an idea of what you can see through an infrared camera (right) compared to a visual spectrum camera (left).  It's the exact same scene in both shots.  The ambient air temperature is 84 degrees F. The thermal image of the grapevine canopy on the right shows a 15 degrees F temperature difference between an exterior leaf (84.5 degrees F) and a completely shaded leaf (69.8 degrees F).  What does it matter? Well, photosynthesis in grapevines is optimal between temperatures of 77 degrees F and 95 degrees F. Shaded leaves fall well below that zone. With this less than optimal contribution, leaf canopy and fruit development and ripening will be less that optimal. In the northern viticulture regions, that can effect fruit and wine quality.

A grape cluster is the bright object in the upper middle of the infrared scene.  The cluster surface is heated up to 93 degrees F, which is 9 degrees F warmer than the air.  Heat fosters the chemical reactions inside the berry that reduce malic acid. In the North, good cluster exposure to the sun is essential to reducing acidity and achieving balanced wines. One of the interesting things I noticed in my thermal pictures is that clusters that heated up during the day due to good sun exposure retained the heat and remained 5-6 degrees F above the ambient air temperature all night long. They did so even on nights when the air temperature dropped to 40 degrees F.  Acidity reduction continued all night long, albeit at a much slower rate as the berries cooled off

    Author

    Tom Plocher, owner, Plocher Vines, LLC.

    Archives

    December 2021
    November 2021
    July 2021

    Categories

    All
    In The Vineyard
    Weird Science
    Wonderful Diversity

    RSS Feed

Powered by Create your own unique website with customizable templates.
  • Home
  • About
    • History
  • Grape Varieties
    • Petite Pearl Grape
    • Crimson Pearl Grape
    • Verona Grape
    • T.P. 1-1-12 Grape
    • T.P. 2-3-51 Grape
  • Purchase Vines
  • Future Vines
  • Blog
  • Contact