The weather forecast for Tifton and many other areas of south Georgia over the next 10 days is not great (> 85 F and < 35% chance of rain). Consequently, growers are wondering if it is a good or bad idea to irrigate cracking peanuts that received a PRE application of Valor. Growers are very conscious of the fact that the potential for Valor injury significantly increases with moisture especially around the time of peanut emergence.
I am of the opinion (based upon 20+ years of research/field experience with Valor) that if a grower needs to irrigate a Valor treated peanut field in order to get a good stand, he/she should do so. What is worse? A crappy peanut stand or Valor injury? The impacts from a poor stand are more detrimental than Valor injury. Production/history/research over the last 20 years has confirmed this. Also, an irrigation event of 0.3″-0.5″ over several hours is not the same as a 2″ rain in 20 minutes!
I recently completed a 3 year study where the main goal was to try and injure the peanut crop by subjecting the field to as much irrigation/rainfall as possible, In these studies, the peanuts received anywhere from 7.8 to 11.2 inches of rainfall/irrigation in the first 30 days after planting (Table 1). Yes, the peanuts did suffer from Valor injury (as expected) but they recovered without yield loss even at a 2X rate (Table 2). UGA does not recommend the use of 6 oz/A of Valor (also not labeled) but this high rate was used to demonstrate peanut tolerance and simulate worse case scenarios.