Peanut Grower Magazine July Column Peanut Notes No. 59 2018
By this time of the year many key inputs have been taken care of for peanut in the Virginia-Carolina region – management of thrips and weeds, applications of gypsum, and use of insecticide for southern corn rootworm. While weeds and foliar-feeding insects can be an issue later in the season and folks are addressing micronutrient issues and deciding whether or not to apply prohexadione calcium, the focus in July and through August and September will be control of disease, in particular stem rot and leaf spot. In 2017 we experienced challenges with sustained disease control in some fields, and our plant pathologists across the region are working hard to define the cause of some of the leaf spot control failures and to develop solutions. Several basic practices can help us stack things in our favor and include: 1) using the recommended rate each time a fungicide is applied, 2) applying fungicides at appropriate intervals and not stretching sprays too far apart, 3) using approaches that optimize coverage and penetration into the canopy (spray volume, pressure), 4) rotate modes of action for fungicides, 5) apply mixtures of different modes of action, and 6) consider a follow up application if heavy rain occurs shortly after application. These fundamentals can help a great deal. Agronomists can go on and on about timely digging. We all know that digging at optimum timing can optimize yield and economic income. But with our acreage and inconsistent weather patterns, sometimes we can’t get to the right field at the right time. One thing that can really help with flexibility at digging is to have healthy peanuts, and the only way to do this is to make sure leaf spot is controlled. Prices for peanuts are certainly lower this year, but even at lower prices, pest management inputs almost always pay for themselves. As we move into an era of unpredictable leaf spot control, at least in the near term based on 2017, a strong and well-designed disease-management program will pay dividends.