No. 11/July 2, 2010
Last Weekly Issue
This is the last weekly issue of the Home, Yard, and Garden Pest Newsletter for 2010. We will continue with issues every other week through July, August, and September. We will follow with a final issue in late October.
Japanese beetles and masked chafers are actively laying eggs at this time in turfgrass. The severity of this infestation is primarily governed by the adult population size and rainfall patterns.
Diplodia Blight Vs Pine Wilt and Dothistroma Blight
We have seen quite a bit of Diplodia blight on pines lately through the clinic. Many Plant Clinic clients ask for help in distinguishing this disease from pine wilt or Dothistroma blight. All three diseases will cause needles to turn brown.
Spruce Rhizosphaera Vs. Cytospora
Rhizosphaera needle cast has been a common Plant Clinic sample in the last two weeks. Spruce trees with purple/brown one- and two-year-old needles are suspect. The newest growth will appear green. Affected needles are cast (dropped).
Bacterial Blight of Ornamentals
Bacterial blight, caused by Pseudomonas syringae, has been common this past spring and early summer. In most plant pathology literature, Pseudomonas syringae is considered a weak pathogen. It requires a wound to enter the plant and does most damage to plants under stress.
Common Teasel: Highway Invasive
Teasel is a frequent sight along Illinois roadways and in abandoned lots. This plant was introduced in the 1700's from Europe, most likely as an ornamental. Teasel prefers open and sunny habitats, often along roadsides and at disturbed sites. Once established in an area, teasel will crowd out native plants and reduce plant diversity.