The second large peak of San Jose scale crawler activity is right around the corner, within the next couple of weeks in middle Georgia. We’ve been collecting a few crawlers on untreated trees for a couple of weeks, but we are now starting to collect considerably higher numbers on our research trees in Fort Valley, GA. As a reminder, scale crawler activity can me monitored with electrical tape and double-sided tape (or vaseline).
Also note that plum curculio (PC) adults are also still active in the orchards. In blocks that still have fruit, if you are and have been on top of your cover sprays, there should not be too much to worry about for PC, but we definitely do not want to slack off on their management either.
With the overlap of San Jose scale and PC activity, there is an opportunity to synergize management efforts for these pests. Please note the PHI for the listed chemicals
In blocks with fruit on the trees, a combination of Imidan (3.5-4 lb; PHI=14 day) with Esteem (6 oz; PHI=14 days) or Centaur (34.5 oz; PHI=14 day) is likely our best (albeit expensive) option, with high efficacy for both PC and scale. Alternatively, another effective option is to tank mix Esteem or Centaur with either Belay (6 fl oz; PHI=21 days), Actara (4.5-5.5 oz; PHI=14 days), or Avaunt (5-6 oz; PHI=14 days). I cannot recommend mixing scale chemistries with a pyrethroid at this time, as the pyrethroids will have a larger negative impact on our natural enemy communities that may provide some natural control of San Jose scales.
In terms of scale-only management, Venerate XC (2 qt applied twice over 7 day period; 4 qt total; PHI=0 days), which is most effective when targeting peak crawler emergence, is an alternative option. Additionally, there is Movento (6-9 fl oz; PHI=7 days), but Movento should be applied only if trees are still flushing with new growth. Lastly, in post-harvest blocks considering applying 2% summer oil in at least 200 gallons of water/acre.
That is a lot to digest, so please contact me if you have any questions.