Green Peanuts and Fungicides Peanut Notes No. 139 2020
I have received a call regarding spraying Green Peanuts (boiling) for disease management. These peanuts are at 70 days. My concern in providing recommendations is post-harvest intervals with fungicides. I don’t know much about green peanuts other than they are very good to eat. We don’t get much discussion about them in agent training. Your guidance on this is greatly appreciated.
Do you know what cultivar he’s growing? I know some green peanut producers use old varieties or lines they have developed themselves. These may be more susceptible to disease than modern lines.
Also, do you know anything about his rotations and the disease(s) he’s trying to control?
I think if he’s growing a conventional cultivar in a well-rotated field with little or no disease right now, and is digging in 30 days, he might get away with no fungicide at all for leaf spot. Stem rot control may be necessary.
I can see a scenario where the grower has planted a susceptible cultivar or line, little to no rotation, and some disease is showing up. In that case control might be needed. I don’t recall ever seeing a fungicide label that specifically mentions green peanuts but if they are not excluded from the label I guess that means they are OK. In that case, the grower could apply a fungicide but should avoid Alto, Approach Prima, Elatus or Convoy since they have a PHI of 30 days or more (you can find this in the fungicide shorter sheet we posted recently). Even in this scenario one spray would probably be all he’d need to apply. If he’s determined to spray more often, I’d go with sulfur since it has a PHI of 0. Some copper based fungicides also have a 0 day PHI. Shorten the spray interval to 10 days if there’s disease pressure.
There is more risk of stem rot damage than of leaf spot losses over the next 30 days. Also, he will want to suppress stem rot and Rhizoctonia so that pods are healthy and bright. Any fungicide that provides effective stem rot control should be fine as long as he avoids those with long PHIs – Elatus or Convoy. I’d probably just go with tebuconazole. Bravo could be added in case leaf spot control is needed. Alto or Approach Prima have a PHI of 30 days and should not be used for leaf spot control.