Text Transcript with Description of Visuals
| Audio | Video |
|---|---|
| In this video, we will explain the concept of rolling onions about one to three weeks prior to lifting or pulling, in order to reduce bacterial bulb rot. | A man drives a small tractor through a field, pulling three sets of rollers behind him. Text on screen reads, rolling onions to reduce bacterial bulb rot. |
| Cornell research has shown that when onions that were dying standing up were rolled, that bacterial bulb rot was reduced by 35 to 57%. | A row down a field shows onions lying on top of the soil. Text on screen reads 35-57% |
| In this Cornell field study where the onions were artificially inoculated with Pantoea agglomerans and Pantoea autonatus, the onions that were not rolled and left to die standing up had 14% bulb rot, while the onions that were rolled had only 6% bulb rot, 57% less. | A bar chart labelled, On farm onion rolling study, cornell twenty twenty two. Artificially inoculated with Pantoea agglomerans and p ananatis. The Y axis is labelled, percentage bacterial bulb rot. Along the x axis is the text, Not rolled died standing up and Rolled. |
| Onions dying standing up. | Text on screen reads, Onions Dying Standing Up |
| This is a slang term that refers to when the onion foliage does not have enough weight to lodge properly because it has been ravished by, for example, onion thrips feeding, stemphyllium leaf blight, downy mildew, or iris yellow spot virus. | Four pictures show the effects of each disease on the onion plant. The onion thrips picture shows light green leaves with white spots. The Stemphylium leaf blight shows the green leaves turning brown and curling up. The downy mildew picture shows the leaves wet, limp and brown and the I Y S V picture shows the leaves yellowing. The next picture shows a field of onions with their necks kinked to one side. |
| Normally, when the onion foliage is healthy, it has enough weight to fall over when the neck tissue softens. | A field of onions with properly lodged tops. Text on screen reads, Properly lodged onions |
| In this New York survey of naturally infected commercial onion fields, in side-by-side comparison, the onions that lodged properly had 9% bulb rot, while the onions that died standing up had 16% bulb rot, almost twice as much. | A bar chart is titled, Survey of commercial onion fields, cornell twenty fifteen, natural infection. The Y axis is labelled, percentage of bacterial bulb rot. The text on the X axis reads, Lodged properly, and, died standing up. |
| To understand this a bit better, we will review some key aspects about how onions become infected with bulb-rotting bacteria. | Text on a gray background reads, How onions are infected with bulb rotting bacterial diseases. |
| The bacteria live in the soil. They usually infect the onion plant in the leaf, axle, or neck region when soil is splash-dispersed onto the foliage, which is favored by free moisture. | A picture shows wet soil in the neck of the onion stem. |
| Onion plants are most susceptible to infection from bulb-rotting bacteria when they are standing upright, have soft necks, and green leaves. | A picture shows the new growth in the neck of an onion as thick, vivid green leaves. |
| When an onion plant is putting on new leaves, the neck region is fairly tight and more resistant to entry from bacteria. | Close-up view of an onion's leaves being pulled aside showing bright green new leaves. Text on screen reads, putting on new leaves. |
| But once the onion plant stops putting on new leaves and the neck softens, bacteria can enter much more easily. | A picture of an onion plant not sprouting new leaves shows the leaves as a dull green color. |
| Once infected, the bacterial disease will spread from the leaves, through the neck, and into the bulb. | A series of images shows the pathway bacteria would travel through an onion. |
| Note that the bacteria need green tissue, which contains moisture to spread through the plant. | View of the top of an onion with the leaves cut off near the bulb. The leaves are wet and bright green. |
| A dry neck is impassable. | View of the top of a dried onion with the leaves cut off near the bulb. The leaves are brown and totally dried out. |
| For these reasons, an upright onion plant with a soft neck and green neck leaves is more susceptible to bacterial infections, whether the plant is dying, standing up, or not. | Right side of the screen shows an onion field with mostly upright leaves. Text on screen reads, 1. Upright onion 2. Soft neck 3. Green neck leaves Is more susceptible to bacterial infections |
| A properly lodged onion plant or one that has been rolled has the neck area protected from splash disperse bacteria, reducing the risk of new infections. | Water pours over and off of a lodged onion with a neck that has been kinked to one side. |
| An onion roller can easily be made out of empty plastic 50-gallon drums for about $1,000. | On-screen text reads, Making an Onion Roller A makeshift roller made out of drums sits behind a tractor. |
| It is essential that the process of rolling onions be gentle, ensuring that the foliage and necks are not injured as this could create entry points for bacterial disease. | A small tractor pulls a makeshift roller over several rows of onions, gently pushing them over. Text on screen reads, Be gentle. |
| A metal roller for example would be too heavy and could damage the necks. | Rust covers a large metal roller. Text on screen reads, too heavy, do not use. |
| Onions that are on track to die standing up are likely to benefit the most from rolling. | Onions in a field with upright leaves. Text on screen reads, likely to benefit the most from rolling |
| But many growers roll their healthy onions too, especially if there is a risk of splashing rain. | Onion field that has been rolled, showing tops that have been pushed over. Text on screen reads, many growers roll their healthy onions too. Especially if there is a risk of splashing rain. Thumbnail images of weather forecast showing rain on several days. |
| We know that rolling onions will protect the crop from new bacterial infections, and since rolling onions is relatively cheap and easy, it ends up being a light enough of a lift for the potential of great benefits. | A tractor pulls a makeshift onion rolling device through an onion field. |
| Finally, a cheap, easy, and effective way to stop the rot. | A lady stands in a field of rolled onions and waves her arms around each other in a rolling motion as she continuously squats and stands. She then rolls through the field. |
| [ No audio ] | A picture of an onion dress as a ninja complete with sword. Text reads, U S D A. U s department of agriculture. Stop the rot. U S D A N I F A S C R I. Nature's ninja. Natures ninja graphic provided courtesy of National Onion association. This work is supported by the stop the rot combating onion bacterial diseases with pathogenomic tools and enhanced management strategies. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and should not be construed to represent any official U S D A or U S government determination or policy. The Cornell University logo. |