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Scale Management Update 2022

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San Jose scale

The 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.

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.

Please note that after February 28, 2022, the EPA is revoking all tolerances for chlorpyrifos on food crops (more info here).

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

For more information, please see the updated peach management guides

Here’s to a great 2022 season!!