No. 9/June 21, 2013

Japanese Beetle Adult Emergence
Japanese beetle adults should be emerging in southern Illinois and will be emerging in central Illinois during the last week of June. They will emerge in northern Illinois during the first week of July. Look for them first on golf courses and other well-watered turf and then on smartweed, one of their favorite host plants.

Pesticide Concerns
It is important when trying to keep landscapes looking as good as possible to be aware of the consequences of some of your actions. Perhaps the likeliest situation where unintended consequences can result is in insecticide and other pesticide applications.

Bagworms will have hatched in southern and central Illinois. They should hatch by the end of the week in northern Illinois. When newly hatched bagworms emerge from their mother’s bag, they climb to the top of shrubs, trees, and any other erect object. They spin out two to three feet of silk which catches in the wind and blows them to new locations. They repeat this process, called ballooning, for about two weeks before settling down to serious feeding.

Boxelder Bugs
Boxelder bugs have two generations per year, with the second generation becoming adult at this time. Boxelder bugs feed primarily as nymphs and adults on seeds of box elder, a native maple. They also feed on the seeds of silver maple and other maples, but apparently not very heavily.

Bacterial Leaf Spot of English Ivy
English Ivy (Hedera helix) is a ground cover/clinging vine with attractive, dark green, and glossy leaves. In the landscape, it is commonly used in shaded areas, where grass and other plants may be difficult to become established. Several leaf spots are known to infect English Ivy, but one of the more common is Bacterial Leaf Spot caused by Xanthomonas campestris pv. Hederae.

Why in the Heck are my Tomato Leaves Curling?
There can be several causes for tomato leaves to roll or curl. Some of the main causes for these symptoms to occur are physiological issues, herbicide exposure, viral infection, or less common problems such as nutritional issues, insect infestation, or phytoplasma infection. When determining the cause of tomato leaf curling/rolling, first take note of any abnormal growing conditions early or during the growing season. Check to see which leaves (old, new, or all) are rolling, determine the direction of the leaf rolling, and whether any other plant parts, including fruit, are showing abnormal symptoms. Therefore, if symptoms are not determined to be a result of virus or herbicide, the cause could be physiological. It takes a bit of detective work to determine the problem and don’t forget there could be a combination of issues.

Quackgrass - Also Known as Devils-grass and Some Other Not So Nice Names
This morning I saw the tallest, thickest stand of quackgrass I think I’ve ever seen growing in a perennial landscape bed.  Certainly, the cool temperatures with timely rains we’ve had this growing season have been very conducive to growth of this cool season, perennial, grassy weed.  It can grow up to 4 feet and from what I saw, it was just about there.  In fact, a quick prayer for the gardener might be in order.  Has he or she simply given up on this weed?  This weed may be choking out the perennials but let’s hope it hasn’t choked out the gardener.

Modified Growing Degree Days (Base 50°F, March 1 through June 14)
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 below with the degree day accumulations above to determine what insect pests could be active in their area.