The following update was prepared by Clemson peanut specialist Dan Anco.
To spray or not to spray, that is the question or at least one of the questions before what looks like a storm coming our way early next week. The answer depends in part on whether or not the peanuts are ready to dig now, and looking back we can remember a similar situation in 2015. In that case 2 years ago, heavy rains prevented getting into fields to do much of anything for a long time. From the looks of things, the forecast for SC doesn’t look like it will be close to what we saw in 2015. If peanut fields are at maturity, they would likely fare better dug and on top of the ground than risk becoming over mature in the ground with the uncertainty of when we might be able to get back into the field to dig (or to spray for runners that might need more season to fully develop), particularly fields with heavy soils or poor drainage. If the field is extremely dry now to the point where there would be digging losses from hard soil, that complicates things and I don’t have any easy answer. A lot there depends on how quick each field might dry out and how mature the pods are currently (if they have time to wait it out). The forecast for mid and late next week looks dry. Peanuts that get rained on if only a day or so should be okay on top of the ground. Without additional rain, what’s above ground will dry out quicker than what’s below ground.
On the other hand, if maturity indicates peanuts aren’t ready to be dug, it is important to keep them protected with fungicides until they are ready. Late leaf spot is difficult to slow down once it gets established, especially with defoliation. If defoliation starts to become severe, additional fungicides are usually too late and we may need to consider early digging.
Source: Clemson Cooperative Extension PeeDee, Spray Peanuts Before the Storm?