Fungicide Systemic Options
Peanut planted in April or early May are nearing 30 to 45 DAP and starting or preparing to receive fungicide applications. In areas that have received ample rains or where applications become delayed a few to several days, the addition or utilization of fungicides with systemic activity can help to provide improved management of late leaf spot. This becomes more helpful for cultivars that have increased susceptibility, such as Virginia types. Multiple product options are available, and this can include supplementing a pint of Bravo with fungicides such as Alto, Aproach Prima, or Domark. Depending on product prices, this may in some cases be more economical (i.e., for a 30/early spray when peanuts are small) than some standalone premix fungicides, though it is good to have many such products available that are effective in managing LLS, and many of these are well suited to applications during subsequent timings.
Planting Dates
Delays in planting and looking at possible replant decisions have prompted questions of how late is okay or too late to plant peanut. We commonly have peanut planted the first week of June and to the 10th, and it has been done before that peanut were planted in the middle of June. However, the overall decreased growing season available the later we plant, combined with maturity requirements of many available runner cultivars, and plant-by dates for insurance decrease the favorability of planting into the middle of June. For example, if planted June 9, 145 days after planting would be November 1. Harvest conditions and frost risk increase tangibly once we get into November. With input costs the way they are, it helps to be within the planting window for insurance where applicable, which likewise generally helps to coincide with growing/harvest conditions.
The following two are from related situations last year.
Paraquat/gramoxone rates
Gramoxone can be sprayed without basagran after cracking. It does in that case tend to cause a little more burn on the peanuts, but they can recover and grow out of it. If a residual product (Dual Magnum/Warrant/Zidua) is going to be sprayed with the gramoxone, it can be better then to add basagran to reduce extra burn. If gramoxone is being applied alone, it can be applied at 5.5 oz/A (3 lb ai/gal formulation) or 8 oz/A (2 lb ai/gal formulation). When applying it alone, NIS at 1 qt/100 gal should be added. Keeping spray pressure at the standard not-greater than 30 PSI also helps to prevent massive penetration into peanut leaf tissues. If basagran were to be added (at half a pint), the gramoxone rate could then be increased to 8 oz/A (3 lb formulation) or 12 ob/A (2 lb formulation).
If preemerge herbicide is missed due to rains
Dr. Marshall advises Dual plus Strongarm would be a good replacement for valor. Could then use dual again at 14 days after planting with Paraquat and Basagran. If additional residual activity is needed later can spray/add Zidua with 30 days after planting spray.
Dan Anco
Extension Peanut Specialist and Associate Professor
Department of Plant and Environmental Sciences
Clemson University – Edisto Research and Education Center
64 Research Road
Blackville, SC 29817
630-207-4926 cell