Here is an update on whats going on in the Peanut fields from Clemson Peanut Specialist Jay Chapin.
Early July shower fronts got most dry areas of the state at least back in the peanut ball game. We have a chance to set some pods and close the canopy on previously stressed runners to finally win the weed war.
Supplies of Bravo (chlorothalonil) have loosened up a bit. A lot of growers didn’t have it when they needed it for one spray, but maybe we’ll have enough the rest of the way.
Once we get the canopy closed and don’t have to mix 2,4-DB with our fungicide applications, we can add manganese as a fungicide tank mix where needed at about 75 DAP. Bailey is more likely to show manganese deficiency. Soil test pH and manganese levels pretty well predict the risk of Mn deficiency (see table on pg. 17 of the 2015 peanut guide).
Rates 0f 0.5 lb actual Mn are needed to solve a Mn deficiency. Rates of liquid formulations that are only providing 0.1 lb Mn aren’t likely to make any difference. Fields that are green with that rate weren’t going to be deficient anyway. Liquid formulations are convenient and are great as long as there is enough Mn in them to get the job done (for example 2 qts of a 10% formulation). Chelated liquid formulations have not been shown to be any more “efficient” than ManGro or other dry manganese sulfate formulations. Page 14 of the peanut guide has a table of dry and liquid Mn rates needed to get 0.5 lb of actual Mn.
Growth Regulator on Bailey
James Thomas initiated a series of Apogee tests on Bailey the past two years showing a consistent yield response. Apogee has been effective in making Bailey canopy size more manageable at harvest. Even with guidance, where staying on the row is no longer a problem, there has been a yield response to Apogee above and beyond any pod loss. Having less bush running through the combine can also speed harvest.
First application (7.25 oz) is when 50% of laterals touch, with a second appl. at 100% row closure. Urea 1 pt or ammonium sulfate 1 lb plus 1% crop oil is recommended. It’s not cheap, but response has justified the cost in these tests. Half rates of Apogee are often not effective in keeping the rows defined at harvest, but half rates have also shown a yield and profit response. Growers who haven’t tried it may want to consider looking at the effect of Apogee on Bailey harvest efficiency.
Mixed Bag of Worms
Some fields just started to get ragged up this week by worms. Most of what I have seen is beet armyworm, but also saw a field where it was almost all yellow striped armyworm and others with fall armyworm, even a few loopers. It doesn’t matter in terms of control – the material of choice is one of the diamides: Belt, Besiege ( diamide + pyrethroid), or Coragen.
The real issue is whether to bother. Usually by the time the sprayer arrives, most of the defoliation is done and the population collapses. The threshold of 4 worms per ft is very conservative. Peanuts have tremendous compensation capability for the foliage, bloom and peg loss to canopy feeders as long as they are not drought stressed. We have seen a yield response to canopy feeders only where the crop is under significant drought or herbicide stress and has not closed the canopy.