May 18, 2020Apple growers put premium on accuracy
Precise cropping of apple trees has become more vital as high density production systems continue to proliferate in the industry.
The subject was on center stage at this year’s International Fruit Tree Association’s (IFTA) annual conference and tours held in Grand Rapids, Michigan.
A panel of growers who discussed the topic of tree trimming consisted of Bridget Engelsma of J Engelsma Orchards in Walker, Michigan; Tom Ferri of T&K Orchards in Ontario, Canada; Jill MacKenzie of Whittier Fruit Farm in Rochester and Appleton, New York; and Suzanne Bishop, director of research and Development with Allan Brothers in Naches, Washington.
Ferri told IFTA conference attendees his operation was searching for a tool to take the guesswork out of apple thinning.
Adopting the precision crop load management model about five years ago has enabled him to be more aggressive and more confident, said Ferri, who farms 20 acres with his wife, Karen, and brother, Joe, in the Georgian Bay region of Ontario.
“We do things a little different here because for Honeycrisp, Mutsu, Cortland, we want apples that are 56s, 64s, and 72,” he said during an IFTA visit to his farm in 2029. While that’s large for most markets, his buyers at the Ontario Food Terminal in Toronto want it. “We get paid a huge premium for that.”
That means a target of 50 apples per tree. In his super spindle systems planted at 10 feet by 18 inches, that results in about 50 bins an acre for Honeycrisp.
Precision crop load management based on the fruitlet growth model minimizes hand-thinning costs and allows him to pick premium fruit and get reliable return bloom, he said.
He’s one of only a few growers in the Ontario region using the model, which was developed by Duane Green of the University of Massachusetts, along with Terence Robinson and Alan Lakso at Cornell University and Phil Schwallier at Michigan State University.
“In 2013 when I first saw this model, I knew it was going to be useful,” Ferri said of the original program developed by his brother, Joe.
“Crop load management is the most important job in the orchard,” Ferri said. “Well, on our farm it is. This precise program has achieved high ceilings.”
This revised program is a three-part series: mechanics, data and output.
(Avery) labels are affixed to 14 fruitlet clusters on a tree, seven per side. They use five sample trees.
“Cluster labels are easy and the simplest things we’ve got, as of yet,” Ferri said. “You get them at Staples, print them at home. The instructions are on the box. It’s pretty simple.
Digital calipers are used to measure precise centimeters on the fruitlets.
“The less data entered, it makes the whole process faster and not as risky for mistakes,” he said. “We push the (counter) button and count the clusters.”
“By now we’ve put on a bloom spray and petal fall spray. The first data collection starts with our fruitlets spray. It’s two-part process. Record the size of all the fruitlets that’s on the 14 labeled clusters. Then count the clusters on the sample tree, top to bottom. This is different than you are used to with the other models. Then, in our area, Georgian Bay, it’s usually about four days when we come back to measure growth.
“When you measure the first tree, if there is 3 millimeters of growth or more, record the size and count the clusters. If there’s not at least 3 millimeters of growth, wait another day. The model will not work properly, so wait.”
“Joe came up with an easy data sheet that shows the tree numbers at the top and the cluster numbers on the left and right side of the tree and we’re able to determine the cluster count. From there, the data is entered into the computer. This takes about 20 minutes or so. This process gets a lot faster as the thinning process goes on.”
Ferri said he starts to “get excited” when a summary sheet is created. “It’s the end column, the number of apples per tree. I’m doing all of the chemical thinning, this is what I want to know. On top, those are our spray dates. The next one is the date we took samples.
“Our base numbers were at 153 apples. The first number is our base measurement, the date of the spray. Four days later, we’ve dropped 100 apples. That’s still telling you to hit them with everything but the kitchen sink. We didn’t spray again; we came down to 78. On July 1, we took another measure, and we’re at 59. It takes time to count the clusters, but in order to know the number of apples per tree, you have to know the clusters. It’s telling me how to adjust the rates for the chemical thinning.
“We broke it top to the bottom, because, obviously, the tops of your trees is always heavier, but if we can see what’s going on up there, it just lets you fine tune things a little more.
After some hand-thinning, we have 50 apples per tree, 25 on a side.
“As you get used to this model for thinning, you will find a little extra time spent earlier in the season getting an accurate count, you’ll save a lot of time later on,” Ferri said. “There is much less hand thinning because you’re getting close to the target. By hitting the target, it ensures quality and consistency.
“I hope seeing this model and how it determines the number of apples per tree, you will give it a try. I think it’s been overlooked big-time. Prove to yourself you can become more aggressive in your chemical thinning. Get closer to your target, reduce your hand-thinning costs and reduce some of the stress that goes along with thinning. I’m a guy carrying a Blackberry. If I can get through this, I know that you can.”
Clothespins work well
Jill MacKenzie works with her husband, Mark, at Whittier Fruit Farm in New York state. They also use the fruitlet growth model.
“There’s so much to be gained from using the fruitlet growth model, we should all be using it,” she said. “Just the thought of it, however, you know this is going to be tedious and you don’t want to do it. We didn’t want to do it. We gave it a shot and didn’t really like our results the first time around so we did it a second time. We did eight blocks this past year.”
“Mark actually did the measuring,” Jill MacKenzie said. “We won’t have a drone or a robot to do this for us in 2020 or 2021. Who knows when we will, so you have to learn how to do this and not lose your mind.
“Set the thing up so you don’t have to keep consulting your notes,” she said. “Use rows and panels to find the trees you are looking for. Set up the block so you’re not wandering the orchard trying to find
your spot. You don’t want to be retracing your steps, but be able to move through there efficiently. Once you have that, whatever block you do, it’s going to be about the same – row No. 1, panel No. 3, row No. 2, panel No. 8, so you don’t start walking tree-to-tree – no wasted time.”
The operation initially used a blue flag on the tree and also for flagging the clusters themselves.
“We are only using it for flagging the tree right now, keeping it low so it can be seen when the leaves emerge. When you count you’re using a clicker. You want to count in a systematic way so that when you get to the end, you look at the clicker and have the number that you can believe in so that you don’t want to feel like you have to count again.
“I didn’t like that blue flag method. It twists around, it gets glued together by your sprays. So I use clothespins that you can buy for a dollar. You use spray paint and make them some bright color and write some numbers on them. You can make a set of these in about an hour – it’s mostly drying time. Put them on the tree so you always know the smallest number labeled on them is higher and you move on down.”
She said spreadsheets are created from the model, leading to effective management of the tree trimming process.
Bridget Engelsma, who is a third-generation member of the farm operated by her father, Jim, takes an aggressive — she called it “extreme” – approach to tree trimming.
“I actually kind of enjoy it,” she said. “There’s something satisfying about seeing the work done in front of you.”
“I guess sometimes I tend to be a bit extreme,” Engelsma said in describing a project that received some reviews from her father.
“(My dad) was in the next room and apparently didn’t realize I was in the other room. I heard him say to my mom, ‘Yeah, it looks pretty rough.’ She says, ‘Was it that bad, Jim?’ And he says, ‘Well, I guess the trees will look halfway decent in a year or two.’
“So yeah, I don’t have any problem trimming heavy. I don’t mind cutting up wood.”
Engelsma described a 2019 trial on her farm, which involved six-year-old, high-density Gale Gala trees. She said the goal was to increase yield and size.
“This particular block, which amounted to about 90 apples per tree, I wanted to see about 50 bins to the acre,” she said.
She was shooting for 145 buds per tree using two cuts. Jim Engelsma’s follow-up of Bridget’s work determined she was still “significantly above” the 145 buds.
“You can absolutely imagine my surprise when, the next day, my dad said, ‘Hey, Bridget, you have to take your boys, walk through there, and take some more wood out,’” Engelsma said. “My jaw hit the floor. Like, ‘Me, take more wood out? You have to be kidding me.’”
The workers then removed two of the larger limbs on each tree. It was then determined a third big limb trim was needed.
“I was so excited” about the 1.5x king bloom mark, Engelsma said. “I thought this was going to be the winning group. Literally every single day I went out there and checked fruit size. I was just convinced this was going to be it. But (Michigan State University Extension’s) Phil Schwallier did warn me. He said, ‘You may not see that big of a difference. Your expectations may not be reality there.’ And I did find that out.”
“I honestly can’t emphasize enough the importance of dormant pruning to your bud load count,” Engelsma said. “Bud counting is a must. My dad told me, ‘If I wouldn’t have counted your buds, I would have said, “Good job in trimming block No. 2. It looks good.’” However, a lot of times we’re not seeing as many buds as are actually out there.
“Counting is tedious, but it is necessary,” she said. “Counting is power. We’re starting early so in our next steps we can do a better job. Repetition is necessary.”
ASE helps management
Bishop described Allan Brothers’ use of artificial spur extinction (ASE), the crop load management method that uses bud-thinning techniques to precisely define where and how much fruit is set on the tree.
The measure of a branch cross-sectional area (BCA) correlates to the ideal number of fruit that a branch and, in turn, a tree should support.
Trunk cross sectional area can also be measured in the first five years of the tree, she said.
“It’s not about following a recipe or set of steps,” Bishop said. “It is learning how to read a tree.”
Allan Brothers turned to the ASE system to get more productive trees.
Previously, she said, it was “very frustrating and why we do what we do when you have 10 acres of fruit and only 50% of the trees are bearing fruit.
A Mafcot wheel is used at the base of the branch. It is kept at approximately 1 centimeter from the trunk to determine the BCA. A 2.5 square centimeter (cm2) BCA branch would call for 15 buds, and if it had only 10, then “you don’t need to prune,” Bishop said. “That’s the major takeaway here. Every time you prune, you’re telling that tree to grow more, and if it already has enough crop load, it’s only going to induce to be even bigger. We don’t want to give that signal at all. So, we’re going to leave that branch as is.”
Bishop said a condition in which another branch with a BCA of 1.1 cm2 presents nine fruit buds when the maximum should be only seven, “what we’d probably do is take out a small, little branch,” Bishop said.
The sum of each of the tree’s branches then results in a total BCA, she said. A figure such as 26.4, multiplied by a crop coefficient of six fruit per BCA (that number can differ based on tree age, variety, and growing region), results in 156 apples on that tree. While that particular number is “pretty low,” Bishop said, it works because the total number of 130 buds, multiplied by clusters of five, results in 650 potential pieces of fruit.
“I still might need to remove 494 fruitlets, so I have plenty of extra fruit to play with,” Bishop said. “That’s the benefit: You’re getting rid of even more of the excess if you’re going down to a one-fruit-per-bud basis.”
Allan Brothers took three years to “get a handle” on ASE and see a difference from conventional blocks that justified their efforts. “Practice is the best way to learn it,” she said. “You have to get out there with the trees and measure.”
She said it gave the operation a way to “manage your labor and from an economic standpoint when you are putting a lot of investment into it and only getting 50% of the crop for it.
“When we’re looking at precision cropping, we’re using a very sophisticated tool – a round piece of plastic that doesn’t take an engineer to operate it, which is great. We use it because it’s very handy.
“You can use the Mafcot wheel to see how many fruit you should set based on the size of the branch. And you can change that number to determine the crop load coefficient. When we’re working in an artificial spur extinction block, there’s some measurements we do that counts the buds and not the fruit itself. You can also count the spurs.
“ASE is a real-life orchard scenario,” she said. “The major takeaway here is (that) every time you prune, you’re telling that tree to grow more. If you already have enough crop load, it’s only going to induce more spurs, so we don’t want to give that signal at all.”
She said us of ASE has reduced biennial bearing, produced more bud renewal in difficult parts of the canopy, allowing significantly more light in the lower part of the canopy. They are also seeing better fruit size and color.
— Gary Pullano, managing editor