Onion Seedbed Update (Oct 1, 2024) | Vidalia Onion Extension News

Onion Seedlings emerging at the Vidalia Onion and Vegetable Research Center on Oct. 1, 2024. These were planted 3 days before Hurricane Helene, and were not emerged at the time Helene passed over us.

Onion Folks,

I hope everyone made it safely through the hurricane. This will be one we will never forget. As of today (Oct.1^st), I know many of you are still without power and reliable cell phone service, and trying to clean up debris and make repairs. The VOVRC did suffer some damage. Several trees down, roof damage to several buildings, and no power predicted until next week or longer.

Several large pine trees blocking the entrance to VOVRC, caused by Hurricane Helene. We also suffered some roof damage to several buildings.

I wanted to give you a quick update about seedbeds. At the time of the Hurricane Helene, we had onion seedbeds that had been emerged for 2+ weeks to some that had not emerged at all from the soil. The visible damage varies greatly among the age of the plants and the location of the farm. Speckling of the leaves, dead tissue, “whiplash”, “sandblasting”, are all ways to describe damage depending on how severely they were hit. In the same field (with multiple planting dates) I have seen some that look ok, and some with dead plants.

Here are some seedbeds in a grower field. It is easy to see which way the wind was blowing. These plants are a little bruised and beat up.

Here is an older onion seedling planted in early September. You can see some speckling or a “sandblasted” appearance on one side of the leaf. This discoloration, caused by wind driven rain and sand, can allow bacteria or fungal pathogens into the plant.

Here is what I want you to keep in mind:

Disease – we are mostly concerned with bacteria and some weaker fungal pathogens. I talked with Dr. Bhabesh Dutta yesterday, and he suggested using the lowest rates of copper and Bravo on young seedbeds. Always check the label of the product you are using, but the lowest labeled rate for many coppers this is 0.75 lbs/acre and Bravo/chlorothalonil this is 1 pint/per acre. I know for many of you, this is what you routinely spray anyway, and some of you may use other fungicides in addition to Bravo. But if not, I would like for you to consider this. It may provide some benefit to the crop.

Here are some onion seedlings with more severe necrosis, or dead tissue, especially on the tips of the leaves. If you look closely, you can even see a few dead plants. These plants were at a very tender stage when the hurricane came through.

Other Questions Regarding Seedbeds:

Here is an onion seedbed where a spot in the field has some broadleaf weeds. Goal may be able to help with a situation like this, but you have to be careful with your rate on young seedlings. Also, Goal will not kill weeds this big, but may help suppress them until the weeds can be hand pulled.

Grass Control in Seedbeds – To sum it up, your best option to get the most grass control with the least amount of crop injury/burn is to use 9-10 oz/A of Select Max 0.97 EC or an equivalent generic (TapOut 0.97 EC or Intensity One 0.97 EC) without any adjuvant or crop oil. These products have a “built-in” adjuvant that is safer than adding your own that helps them work with less crop injury. This is different from the regular “Select”. It needs crop oil to work well, but this can cause a lot more crop injury.

Broadleaf/Other Weed Control in Seedbeds – Goal 2XL is an option, but not a silver bullet. The longstanding UGA Extension (Dr. Stanley Culpepper) recommendation for using Goal 2XL is this:

“Seeded dry bulb onions: Apply 3–8 oz/A of Goal 2XL (1.5–4 oz/A of Goaltender) in a minimum of 40 GPA and with no less than 20 psi. Apply when onions have at least 3 true leaves, when weeds are 1″ or smaller, and when conditions are not cool, wet, and/or cloudy. Use lower rates on younger onions with 3–4 oz/A of Goal 2XL ideal for onion in the 3–4-leaf stage. Sequential applications may be made but do not exceed 2 pt/A/season of Goal 2 XL (1 pt/A for Goaltender). The rates discussed here are lower than suggested on the label and are provided to help avoid severe injury; obviously less weed control is expected with lower rates.”

That is all for now. Stay Safe!