Tuesday, May 28, 2024

Enhance Leaf Spot Control

David Jordan
David Jordan
North Carolina
State University

By this time of the year, many key inputs have been taken care of for peanut in the Virginia-Carolina region, such as management of thrips and weeds, applications of gypsum and use of insecticides 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.

leaf spotWe 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.[divider]

Dealing With Late Planting

Kris Balkcom
Kris Balkcom
Auburn University

I know many producers didn’t get to plant as early as planned this year because of the cooler temperatures in April, dry weather in early May or the three weeks of rain the end of May through the beginning of June. This made for a much narrower planting window.

Many areas experienced a three to four week dry period after the start of planting. Some of you left off Valor since no rain was in the forecast. It seems like the last few years not as many producers have been burning their peanuts. Some of that is because good showers behind planting have activated the herbicides giving good control of weeds earlier.

As to the fear of burning peanuts, recent research has showed us no yield losses from burning our peanuts back with gramoxone early. Take advantage of the opportunity to kill that flush of weeds with the combination of gramoxone and 2,4DB if you left off your pre-emergence herbicides or didn’t get good control from the dry period after planting. Also add in other products like Dual Magnum, Zidua, Warrant or Outlook to get some residual weed control in the soil.

I have received lots of calls about late-planted peanuts. Don’t beat yourself up over the fact that you couldn’t get in there and plant them as early as you wanted. Let’s just take the hand we were dealt and work with it. I want to encourage you to manage those fields just as you would have had you gotten them planted earlier.

I say this because you still have time to produce a good crop of peanuts. I have planted several tests as late as June 15-25 to see how well those peanuts would produce. They have averaged anywhere from 4,500 to 6,000 pounds per acre. Obviously, the yields vary depending on your rainfall and fall temperatures. I hope that you have a prosperous growing season and I look forward to seeing you around.[divider]

Work On Reducing Stress

Scott Monfort
Scott Monfort
University of Georgia

I had the opportunity to talk with several experienced and lifelong peanut growers the other day about the differences and challenges faced over their careers. The one thing I heard in the conversation was how they compared any one year to what they called the “typical growing season.”

I have heard this comparison many times over my career. I have even used it myself in talks to growers, etc. I am confident I have never observed one of these “typical” growing seasons and more than likely never will. Why do I bring this up as we move into July?

The main reason is to remind growers, Extension agents and consultants to stay on your toes. Growers have already experienced extreme situations since May 1, and I expect Mother Nature to stir things up even further.

Georgia growers started the year off on a good note with decent weather conditions, good quality seed and time to get peanuts planted and off to a good start. Exactly what we consider it would be like in a typical year until things drastically changed. Roughly 50 to 60 percent of the crop was planted in the ideal planting window of May 1-15 with the remainder of the crop scattered from late May to mid-June because of rainy conditions.

The rainy, cloudy weather has caused a shallower than normal root system in some areas. This could reduce the productivity of the plants if stress develops in July and August. All growers can do is try to be as timely as possible with pest control measures and irrigation management programs to help reduce any potential stress on the peanut crop for the remainder of the year, which is easier said than done, I know.

Keep in mind the following things as we move into July and August:

• Know what is going on in your field – hire a consultant or scout. This will help keep you timely and effective with your pest management programs.

• Do not cut corners on disease management.

• Watch your input costs.

• It is often easier to prevent a problem than fix one. If you have a question about a product or a recommendation, call your county agent and have them get in touch with a specialist if needed.

• Let your county Extension Agent know if you are experiencing a higher than normal level of TSWV.

Also, please let your agent know if you are observing any peg deterioration. This will help UGA specialists determine if peg deterioration observed in Georgia last year is a recurring problem in 2018.[divider]

Avoid Disruptions In Flowering

Jason Woodward
Jason Woodward
Texas Agri-Life
Plant Pathologist

Peanuts continue to actively grow; however, much of the crop is at or will soon approach peak bloom. Peanut is an indeterminant crop, which means the number of flowers will continue to increase over the next several weeks. Flower development will eventually begin to decline as pegs and pods form and start to mature.

This results from developing pods competing with vegetative components of the plant for carbohydrates and nutrients. In order to maximize yield and grade, it is imperative that optimal crop conditions be maintained as much as possible.

Extreme conditions such as high temperatures, moisture stress and low humidity can have a negative impact on flowering, limiting the number of flowers produced and reduce pollination.

While peanut plants are capable of compensating for such situations, disruptions in flowering that occur during the latter part of the season will result in a split maturity.

peanut flowerDelays in pod set and differences in maturity result in challenges later in the season when making harvest decisions.

Irrigation timing and the amount applied is important during this time, as crop water demand increases substantially as plants continue to transition from vegetative growth to reproductive stages and later pod development and maturity.

Attention should be paid to irrigation pumping capacity, as well as water quality especially in areas where little rainfall has been received. While peanuts respond well to irrigation, precipitation is also required to leach salts that may accumulate from the constant application of irrigation water.

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