This image has an empty alt attribute; its file name is sjs-300x225.png
San Jose scale

These above 50°F weather makes for a lovely day, but the scale insects enjoy it too, becoming developmentally active above 51°F. That means it is a good time to nip these guys in the bud.

For delayed dormant timing, apply dormant horticultural oil at a rate of 1.5% oil to water. It is recommended to apply the oil:water mixture at high gallonage in order to maximize coverage. As you have probably heard me say over and over again, if you are applying the delayed-dormant application to pre-pruned trees, then it is important to aim for 150-200 gal/acre to get effective coverage, especially in areas with a history of scale pressure. If the trees have already been pruned, then lowering the rate down to 100 gal/acre seems to be effective. Increasing the rate to 3% oil at 100 gal/acre may also achieve effective coverage.

Additionally, combining an insect grower regulator, such as Centaur or Esteem with the oil can enhance the control of the scale. Similarly, combining Venerate with the delayed-dormant oil application has also shown to significantly suppress scale numbers compared to oil alone.

Also, note that after the recent court order, chlorpyrifos tolerances are now in effect and can be used again in accordance to the registered labels (more info here). As used in the past, chlorpyrifos may help suppress both scale insects and borers when applied with oil at bud swell.

Also note, do not apply oil sprays within 2 weeks of (before or after) making a spray that contains sulfur.

For more information and additional management options, please see the updated peach management guides:

Here’s to a great 2024 season!!

Posted in: