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Adult twospotted spider mite, Tetranychus urticae.

Monitor for Spider Mites—Bloom to Postbloom

Monitor orchards for both spider mites and their predators at least once every 2 weeks from March to early May. Observe individual leaves in the lower interior portions of trees throughout the orchard for light stippling that may indicate mite feeding. Sample a minimum of 5 trees per block and 15 leaves per tree, focusing on leaves in the lower interior region of the tree.

The best way to detect the presence of mite eggs, hatched spider mites, and predators is to use a hand lens and examine leaves. As a rule of thumb, if more eggs than spider mites are present, the mite population is increasing.

Miticides in the early part of the season are seldom required if predators are already present. Monitor predatory mites along with pest mites to determine predatory mite:pest mite ratios. Treatment is not needed if either of the following is true:

  • The predator:pest mite ratio is greater than 1:10.
  • At least half the leaves with pest mites have at least one predatory mite on them.

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