Performance of Prohexadione Calcium at Reduced Rates in Mississippi Peanuts.

Unwanted or unnecessary vegetation can cause a multitude of problems in peanut production systems, and plant growth regulators can play vital roles in managing excess vegetative growth. Peanut can produce excessive vine growth, especially when grown in highly fertile soils and/or when water is not a limiting factor. Increases in vegetation do not always lead to increases in peanut pod yield potential; in fact, excess vegetative production can rob key nutrients and photosynthates that are needed for reproductive growth. Other problems can occur when peanut canopies are excessive. The loss of clearly-defined rows can become a problem when digging peanuts. Disease incidence can increase when canopies are more dense than normal, in part due to inhibiting foliar-applied fungicide contact with the lower leaves or soil surface, where a number of pathogens can be problematic. The objective of this research was to evaluate pod yield and canopy response to three rates of prohexadione calcium at three on-farm locations across the state of Mississippi in 2017. Treatments included a 1x labeled rate (507.6 g ha-1), a .75x rate, a .5x rate and an untreated control. Each treatment was sprayed at 50% vine lap and followed up with the same treatment two weeks later. Data was pooled across locations and we observed a significant yield increase across all treatments receiving a prohexadione calcium application compared to the untreated control. The .75x rate yielded 11% better than non-sprayed with no yield differences among sprayed treatments. Ultimately, this data will be used to control vine growth and improve yield in peanut in Mississippi.