Zidua in Peanuts (Prostko)
It appears as though the following statement on the supplemental Zidua peanut label has many people confused:
“Apply Zidua as a broadcast spray to peanut from “at-cracking” stage to first true leaf stage through beginning of pod development.”
A few points to consider:
a) For whatever reason, most people do not talk about peanut stages of growth as frequently as they do with other crops such as soybean and corn. However, there are some “official” stages of growth for peanuts (Figure 1).
|Figure 1. Peanut stages of growth (K.J. Boote. 1982. Peanut Science 9:35-40).|
a) Zidua is not labeled for PRE use in peanut for good reason. Peanuts do not have a 2X tolerance to PRE applications. In my research since 1997, PRE applications of 2X rates have caused peanut yield losses ranging from 7% to 25%. The 1X rate of Zidua is 1.5-2.0 oz/A (85WG) or 2.50-3.25 oz/A (4.17SC).
b) I have applied Zidua as early as V2-V3 (10 DAP) and as late as R6 (90 DAP) with no yield loss. However, applications made at V2-V3 did cause more peanut injury than later applications but this injury did not result in yield loss.
c) I have applied the equivalent of 8 oz/A of 85DG or 13 oz/A of 4.17SC (4X rate) at 44-51 DAP (R1 to R2 stage) with no yield loss. Not suggesting that growers do this but this is a good indicator of the tolerance of peanuts to POST applications of Zidua.
d) **Bottom line, growers should never apply Zidua PRE and POST applications can be made from the V2 through R3 stages of growth.