Exposed female SJS

Good afternoon everyone, we have started to see some San Jose scale crawler activity in middle GA. With the relatively cool spring weather we have been having, the first large peak of San Jose scale crawler activity is going to be similarly timed compared to last year, which I anticipate to occur within approximately 7-10 days from now in Fort Valley, GA.

Following the degree day (DD) timing starting at February 1st using a base of 51oF and a max of 90oF, at this point last year we had accumulated 537 DD and this year we are at 579 DD (UGA Weather). I anticipate the first main peak of crawler activity to occur at approximately 700 DD since Feb. 1, which will be in roughly a week in Fort Valley. As such, for the Ridge, (Clarks Hill, SC is at 462 DD) I’d expect the peak to be in about a week after Fort Valley and then the upstate a week or so after that.

This image has an empty alt attribute; its file name is P6141363-1024x908.jpg
Closeup of a San Jose crawler on double-sided tape.

Remember that scale activity can be monitored relatively easy (although a bit tedious). Visually inspect limbs for live scale and/or wrap a branch with a strip of electrical tape plus a strip of double sided tape around that (see image below). Focus particularly on trees in blocks with a known history of scale issues.

This image has an empty alt attribute; its file name is IMG_3193-1024x723.jpg
Monitoring San Jose scale crawlers with double-sided tape

Management of San Jose crawlers is not necessary for all blocks peaches if all blocks received two dormant oil applications this season. If a dormant spray was missed or you have a block with chronic scale issues, then I would suggest considering crawler management.

Once crawler activity begins to increase, consider management insect grower regulators, such as Esteem (6 oz/acre) or Centaur (34.5 oz/acre). Alternatively, when targeting the scale crawlers, Venerate XC (2 qt/acre applied twice over a 7 day period; 4 qt total) or diatomaceous earth (i.e. Celite 610 @ 10 lb/acre applied 3-4 times bi-weekly) have both showed efficacy at suppressing San Jose scale.

If management occurs later, once the crawlers have already settled and/or you cannot find active crawlers in a block with a history of scale, it may be best to treat with Movento (6-9 fl oz/acre). Note that Movento should be applied once the trees have substantial leaf area, flushing new growth, and should be tank mixed with an adjuvant that has spreading and penetrating properties. Anecdotally, I have applied Movento late April and have had good success.

As always, please check out the management guide for more detailed recommendations. And don’t hesitate to let me know if you have any questions.

Last thing, if you are bored and want to learn a bit more about, check out the UGA circular about San Jose scale.

Take care, everyone!

Posted in: