Monthly Archives: June 2021

CM and OFM Degree Day Update, 6.21.21

As of June 21, 868 and 997 DD have accumulated since CM biofix at Winchester and Red Hill (central VA), respectively. Some growers choose to apply a third spray against 1st brood CM, which would occur about 2 weeks after the 550 DD point, which was on June 7 and June 4 at Winchester and Red Hill, respectively. This spray would be warranted if captures of CM in pheromone traps continue to exceed the 5 moths/trap/week threshold. Otherwise, the next spray for CM would target the onset of 2nd brood larval emergence, as follows: Rimon at 1250 – 1320 DD, Assail, Belay, or Esteem at 1350 DD, all others at 1450 DD. As we approach the first optimal timing against 2nd brood CM larvae, I will resume posting DD graphs twice weekly.

As of June 21, 1578 DD have accumulated since OFM biofix at Winchester, and we are beyond the point at which sprays against 2nd brood OFM larvae are warranted. The next optimal timings against OFM will target the start of 3rd brood larval emergence, as follows: PEACH – Assail at 2000 – 2100 DD, all others at 2100 – 2200 DD; APPLE – Rimon at 2300 – 2350 DD, Assail or Belay at 2350 – 2400 DD, all others at 2450 – 2500 DD. I will also resume twice weekly postings of DD graphs for OFM as we approach the first optimal timing.