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Update from the Field: Plum curculio and San Jose scale

Hello everyone,

Quick update from the field. The field generation of plum curculio are emerging now, so activity is on the rise. Just as a reminder Imidan, Actara, Belay, and Avaunt provide excellent control and good residual control of plum curculio and Oriental fruit moth. As such, rotation of Imidan, Actara, Belay, or Avaunt with pyrethroids should help protect the resistance-prone pyrethroid class. Check out the 2021 management guide for current recommendations for plum curculio management.

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Plum curculio adult.

San Jose scale has been a little quiet, but I am seeing a little more activity with them too. With the degree day timings, I expect the second large peak of crawler activity to occur within the next 10-14 days in middle Georgia (~1,900 degree days). Thus, the ridge has about two weeks and upstate SC has about three weeks from now until we would expect to see a peak in crawler activity.  As a reminder, scale crawler activity can me monitored with electrical tape and double-sided tape (or vaseline).

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San Jose scale crawler.

If you have blocks where you have had a history of San Jose scale issues or have noticed problems this season, 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 Esteem or Centaur alone are good options, or 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.  

Lastly, in post-harvest blocks, consider applying 2% summer oil in at least 200 gallons of water/acre.

Please note that that while crawlers seem to be active all season long, there will be a third peak of activity in early August. I will post a reminder when we get closer to that date. That may be another option for a knocking the scale population back prior to our normal dormant management options.

I hope everyone is doing well!