No. 7/June 8, 2015
Peach Leaf Curl
Recently, there have been a number of requests for information on how to control peach leaf curl, a disease caused by the fungal pathogen Taphrina deformans. Peach leaf curl is one of the most common diseases of peach and nectarines in home plantings. This disease also occurs in commercial orchards, but is much less common due to the frequent use of fungicides. A number of other Taphrina species are known to cause several common diseases in the landscape including oak leaf blister and plum pockets.
Lightning damage to trees may be one of the easiest problems to diagnose, and also potentially one of the most heartbreaking when the big old tree dies. However, lightning damage doesn't always mean death. Unfortunately, there's not much to be done once the lightning has struck.
Convict caterpillars have been found feeding heavily on daylily foliage in Metropolis in far southern Illinois. In previous years they have also decimated the foliage of surprise lilies in that area of the state. They also feed on spider lilies, narcissus, and amaryllis in the southeastern U.S., feeding not only on the foliage, but also on bulbs and rhizomes.
Bagworms have hatched throughout the state and are a little earlier than normal. Treatment is recommended in southern Illinois at this time as they have completed their ballooning and are settling down to feed in earnest. They will still be ballooning farther north, so treatment should be effective in central and northern Illinois after mid-June.
Modified Growing Degree Days (Base 50°F, March 1 through June 4)
Insect development is temperature dependent. We can use degree days to help predict insect emergence and activity. Home, Yard, and Garden readers can use the links in this article with the degree day accumulations listed to determine what insect pests could be active in their area.
Viburnum Leaf Beetle Activity Reported
Reports of viburnum leaf beetle injury continue to come in out of Cook and DuPage counties. A relatively new pest in Illinois, we saw feeding begin to be more noticed in 2014. That trend continues this summer.
Be on the Lookout for Giant Hogweed
Now is the time of year when Giant Hogweed starts to bloom. This invader has been found in Illinois a handful of times in the northeastern part of the state but we do not know of any active populations at this point.