North Carolina State University
A Lot To Do This Month
June brings a number of key production and pest management decisions for Virginia-type peanut. The calcium needs of both Virginia market types and jumbo runners we are currently growing require gypsum application during flowering and kernel development. Application is generally made around 40 days after planting. It is important to apply gypsum when the peanut canopy has developed enough to protect gypsum on the soil surface in the fruiting zone from being washed away. Sometimes, we apply gypsum a little early and are susceptible to the occasional “frog strangler” in late June.
It’s also the time to make decisions on controlling southern corn rootworm with insecticide. In the V-C region, we have a good risk index to help make this decision. For later-planted peanut, we could still have some issues with thrips, so a timely application of acephate can pay dividends if thrips pressure is heavy.
Naturally weeds may continue to be a problem, and being as timely on application of postemergence herbicides is important. Do things to help the PPO-inhibiting herbicides perform as well as possible – spray small weeds, increase the spray volume and slow down. Developing a sound fungicide program will be important as you move into July. With the selection of fungicides we currently have, the key is to be timely and on a good spray schedule and rotate chemistry. I’ve rattled off a lot of things to do in June. Timely implementation of these is the key!
University of Georgia
Effective Fungicide Programs
Growers are slowly transitioning from planting to crop management as we move into June. The good news is most of the early planted peanuts are up and looking promising even with the lack of rain in late May.
Key things growers should keep in front of are weed escapes, early season insects and disease issues. One way to ensure these issues don’t get out of control is to walk your peanut fields at least once a week or hire a consultant or crop scout. A crop consultant or scout, dedicated to your peanuts, will ensure you spray the right pesticide at the right time to manage the specific pest or pathogen. Typically, the cost of having someone scout your crop is far less than the cost of the extra pesticides.
With peanut acreage remaining high for the second year in Georgia, growers are opting to plant more peanuts under short rotations along with trying to minimize inputs to remain profitable. Growers can stand to make reductions in inputs under good rotations and cultural practices; however, the reduction in rotations and some cultural practices in the last two years have caused a significant increase in disease risk. For this reason, growers need to consider more effective fungicide programs rather than eliminating them. Feel free to contact your county Extension agent for up-to-date information or pressing issues regarding peanut production in your area.
Best Time For Herbicides
Hopefully everyone has their peanut crop in the ground and it’s off to a good start. I know that it is difficult for some of us to get back around after planting to take care of some timely issues, one being herbicide applications. For some of us, our planting season runs a lot longer than others and it is awhile before we get back to those first- planted peanuts. We have to be timely with our herbicide sprays and not let the weeds get too big to have good control. Even though certain herbicides do a fantastic job on weeds two to three inches, it doesn’t mean the same herbicide will be effective with the same weed at five to six inches tall.
Also be mindful of the time of day and weather conditions when thinking of applying certain herbicides. Most applications are best from mid-morning to mid-afternoon. Pay attention to the temperature since most herbicides perform better when applied during the heat of the day than when we have cooler weather to pass through. Also, rain fastness has a huge effect on how well the herbicide performs if sprayed too close to a rain event.
Texas Agri-Life Extension
The majority of runner and Virginia peanuts have been planted in the Southwest; however, Spanish-type cultivars still have time to mature with planting dates into June. In this case, warmer soil temperatures may facilitate germination, but soil moisture remains the most important factor required for seed to germinate. These conditions should lead to fast stand establishment and help minimize the potential for damage caused by the application of preplant herbicides.
For earlier planted peanuts, now is the time to assess nodulation, choose herbicides for initial weed flushes and consider irrigation scheduling. When assessing nodulation, dig plants carefully as not to dislodge nodules by pulling plants from soil. This will lead to an underestimation of nodulation. An average of 20 active nodules per plants is considered excellent, and supplemental nitrogen is not needed. With 10 or less nodules, the plant will
likely benefit from additional nitrogen. Active nodules have a salmon pink to red color. If nitrogen is needed, it should be applied in a single application less than 30 pounds per acre. Rates in excess of this can increase disease problems.
Knowing potential weed problems within a field will aid in the selection of herbicides needed to complement preplant and preemergence products. Consult herbicide labels for the spectrum of activity and use rates.
Finally, changes in irrigation strategy are needed as plants move from vegetative to reproductive growth. In general, water use is low-to-moderate during vegetative stages, but increases substantially following the transition to flowering and pegging, and remaining very high through pod fill. Uniform application of irrigation water is needed to maximize production and maturity. This is equally important when center pivots are used to make fertilizers or pesticide applications.