No. 11/July 11, 2016
Wild Parsnip
The cultivated parsnip that we eat heralds from the appropriately named wild parsnip (Pastinaca sativa). Wild parsnip has recently been making the rounds on social media, as the plant can leave individuals with burn-like blisters on their skin. Severe cases appear somewhat gruesome, though according to some, it is still not as bad as the itch of poison ivy.
Black Knot
Black knot is a fungal disease that affects most cultivated and wild Prunus species in the United States, including cherry, plum, and chokecherry trees. The disease is caused by the fungus Apiosporina morbosa (also known as Dibotryon morbosum), and can be incredibly destructive once established. Symptoms are not obvious in the early stages.
Iron Chlorosis and Manganese Chlorosis of Shade Trees
Are the leaves on your tree a little more yellow than you remember them being in previous years? They may be chlorotic, a condition in which leaves turn yellow as a result of destruction of chlorophyll or lack of chlorophyll production. In most cases, chlorosis is the result of a nutrient deficiency resulting from either a lack of nutrients, or the inability of the plant to uptake the nutrients. Iron (Fe) and manganese (Mn) deficiencies are two of the most common nutrient deficiencies seen in woody landscape plants.
White Grubs
White grub eggs are primarily laid during the first half of July. In southern Illinois, most of the eggs have been laid; in northern Illinois, many of the eggs will be laid during the next couple of weeks. Where these eggs are laid and how many are laid rely on several factors, which determine whether preventative insecticides need to be applied to turf during July.
Billbug
Bluegrass billbugs have been reported as numerous in northeastern Illinois. Bluegrass billbug occurs throughout the state, with hunting billbug being present in southern Illinois on zoysia and bermudagrass.
Planthopper
We have been receiving reports of planthoppers in various areas of the state. The nymphs of these insects are covered with and leave behind white, fluffy tufts of waxy strands that get stuck on leaves and stems by the honeydew that these insects excrete. They are unlikely to cause enough damage to warrant control.
Daylily Leafminer
Daylily leafminer, Ophiomyia kwansonis, is being found in many areas of Illinois. This Asian native was first detected in Florida in 2011 and has since spread through much of the U.S., apparently by the movement of infested plants.