No. 12/July 16, 2012
We've been getting calls about flying lint and tiny drifting angels from throughout the state. These are the winged adults of woolly aphids appearing as a white fuzzy, close to ¼ inch in diameter, which seems to float through the air. If you try to catch one, you soon realize that it is capable of powered flight. These aphids are green to blue and covered with white waxy strands that stand out from the body.
Pest of hollyhock, including hollyhock weevils and hollyhock plant bugs, are discussed.
Genista caterpillar, Uresiphita reversalis, is common this year on wild indigo, Baptisia. The caterpillars web the leaves together with silk, eat holes in the leaves, and eat leaf margins to the midvein. There are two generations per year. This is probably the second generation as we had some reports in early June.
We have been receiving reports of high numbers of sod webworms throughout the state. Sod webworm caterpillars are more common in nonirrigated turf in Illinois during seasons of drought. The larvae are very susceptible to microsporidia disease, particularly under cool, damp conditions.
Testing for Bacterial Leaf Scorch of Trees
Scorch may be of the noninfectious or infectious type. Environmental stress, root injury, drought, and many other factors may cause leaf margin necrosis, a condition we call scorch. It is usually widespread in a tree and is fairly uniform. Such a condition is not necessarily repeated in following years and is noninfectious. Unfortunately, we are seeing a lot of scorch symptoms on leaves brought on by this season's environmental stress.
Botryosphaeria Dieback of Rhododendron
Several fungal pathogens are known to cause wilt and dieback on rhododendrons. Phytophthora Dieback and Phytophthora Root Rot are often our first suspects when diagnosing in the field. Phytophthora dieback usually appears during flushes of new growth. The disease causes individual shoots and leaves of new growth to wilt and curl inward.
The tomato is one of the more popular vegetable grown in home gardens. With it, however, come a plethora of problems and this season has no shortage. A number of the problems that gardeners may be seeing are discussed.
The Drought of 2012--How Should I Water my Lawn?
Is my lawn dead? I hear that question every year, but particularly this summer. The good news is that turfgrasses have an excellent dormancy mechanism that allows them to tolerate most droughts. The bad news is that there is no way to visually tell whether grass is dead or just dormant.