July pest watch (16951 bytes)

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  • Continue slug control. See June tips.
  • Watch for sugar-like droppings on tomato plants. These are a sign of psyllids--tiny, flat, oval insects--on the undersides of the leaves. Top leaves may be curled and yellowed and leaf veins may be purpling. As soon as possible, spray with insecticidal soap or dust with sulfur.  CSU Fact sheets 2.945 and 5.540
  • Thoroughly spray aphid- or spider mite-infested plants with insecticidal soap or a strong water spray. Repeat as needed.
  • Hand-pick and destroy Mexican bean beetles. Squash the spiny, yellow larvae found under skeletonized bean leaves.
  • Dust or spray Bt (Bacillus thuringiensis) if hornworms on tomatoes or cabbageworms on broccoli, cabbage, and cauliflower are causing a lot of damage. CSU Fact sheet 5.556
  • If you sprayed fruit trees for coddling moths once in the spring, it's time to spray again now.
  • Survey American elms for wilting and yellowing leaves and branches, initial symptoms of Dutch elm disease. If these symptoms are present, immediate action is required. See CSU Fact sheet 5.506 for control and sanitation measures.

For more information:

The Insects of July

View Pest Alert newsletters 1994 to present


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Date last revised: 01/05/2010