Doctoral student Johanny Castro Chinchilla speaks about his research on postharvest diseases in apples. Examples of infected fruit are on the table.
Magni Hussain, a doctoral graduate assistant, speaks about his orchard robotics research. He is joined by adviser and ag engineering professor Long He.
Long He, an ag engineering professor, speaks about his team's work on automated crop load management for apples.
An apple research block at the Fruit Research and Extension Center.
Doctoral student Johanny Castro Chinchilla speaks about his research on postharvest diseases in apples. Examples of infected fruit are on the table.
BIGLERVILLE, Pa. — Penn State orchard researchers are developing strategies to automate apple production, and to protect trees and fruit from disease.
The scientists showed off their work July 7 at the university’s Fruit Research and Extension Center.
Ag engineer Long He leads a team that is building robots to prune trees, count buds, and thin blossoms and green fruit.
“Hopefully in the future we can fully replace the human labor by our robotic system,” said Xinyang Mu, a doctoral graduate assistant on the project.
To develop the blossom thinning tool, Mu collected hundreds of thousands of orchard images to teach the machine what apple blooms look like.
The camera can identify blooms with 84% accuracy, which Mu said is acceptable.
The robot moves a spray nozzle to a targeted flower, spritzes it with chemical thinner and moves on.
Spraying only the chosen buds, instead of a larger swath of the tree canopy, will reduce usage of thinning chemicals, a cost savings to farmers.
Still, the robotic system will be limited to canopy configurations that are relatively flat, such as high density trellis systems, Mu said.
Magni Hussain, a doctoral graduate assistant, has a slightly different challenge in developing the tool to thin green fruits.
Magni Hussain, a doctoral graduate assistant, speaks about his orchard robotics research. He is joined by adviser and ag engineering professor Long He.
Like Mu’s machine, Hussain’s needs to detect the targets for thinning. But because Hussain needs to physically remove the excessive fruits, his machine determines the best angle of approach while avoiding tree limbs or the fruits that will be kept.
Part of the project is developing path sequencing.
“That basically tells my robot the best way to get from its current position over to the target fruit, as well as be able to go between different fruit within a cluster in the most efficient path possible,” he said.
The tool is showing promise for removing multiple fruits within a cluster, but Hussain wants to speed it up. For current decisions, computation can take 10 minutes or more, he said.
Other researchers are working on ways to manage pathogens that can rob yield and kill trees.
Johanny Castro Chinchilla, a Ph.D. student, has identified Pennsylvania’s most important postharvest diseases and how they infect fruit.
Castro swabbed a host of surfaces in packinghouses, and tested crop wash water, and the air in cold rooms.
The most common postharvest pathogen in Pennsylvania is alternaria, which causes a black rot. About 40% of randomly sampled apples had this disease.
Bullseye rot is the second most common postharvest problem, appearing in 20 to 30% of samples. The fruit is infected in the field but needs three or four months in cold storage before symptoms show up.
“This is a fungus that is very particular,” Castro said.
To manage alternaria, bullseye rot and other postharvest diseases that come from the field, growers need a good fungicide program. Merivon should be the last spray before harvest, said Kari Peter, Castro’s adviser.
Some diseases infect the fruit after it’s in the bins. Penicillium is the most important of these diseases, appearing in 14% of samples. Cleaning the cold room is the best way to combat this pathogen, Castro said.
Long He, an ag engineering professor, speaks about his team's work on automated crop load management for apples.
Castro is also looking at alternative products, such as essential oils, to use before harvest. The drawback, he said, is these protectants top out at 60 to 80% efficacy, whereas standard fungicides approach 100% control.
Peter, a tree fruit pathologist, has been running a demonstration project for biofumigation, a process used to clear soilborne pathogens ahead of a new orchard planting.
Sorghum sudangrass and rapeseed release compounds that kill nematodes when chopped up and incorporated into the soil. Unlike manufactured fumigants, biofumigants cause little harm to beneficial organisms, Peter said.
Biofumigation has been tested at the fruit research center before, but it has taken on new appeal because the technique kills dagger nematodes.
These common soil pests spread the tobacco and tomato ringspot viruses, which could be a risk factor for rapid apple decline.
The biggest challenge Peter found for biofumigating was incorporating the chopped cover crops into the soil. Discing left a lot of plant matter on the soil surface, where the nematode-killing compounds will provide little benefit.
Peter used a rotavator on several small plots, but even that tool had its limitations. A moldboard plow might even be an option, she said.
Even so, Peter recorded a decline in nematode populations after treatment. The nematodes will eventually bounce back, but biofumigation at least buys time.
“It gives those first few years, those tender years in the very beginning, a good shot for your tree to grow without any virus issues lurking,” she said.
An apple research block at the Fruit Research and Extension Center.
The issue that quickly kills apple trees has been one of the most baffling orchard maladies of the past decade. And though the list of suspects is coming into focus, the cause or causes remain uncertain.
FREC, as the center is known, is the oldest of Penn State's four current research farms outside University Park.
A study recently found planting peach trees closer together yields fewer peaches per tree, but more bushels of fruit per acre.
BIGLERVILLE, Pa. — The Japanese orchard bee may be the hero of the Adams County apple industry.
Phil Gruber is the news editor at Lancaster Farming. He can be reached at 717-721-4427 or pgruber@lancasterfarming.com. Follow him @PhilLancFarming on Twitter.
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