InteractiveTurf Newsletter newsletter@interactiveturf.com July 23, 2003 We are so COOL (and wet) !! Weather review: Since July 7, much cooler air has settled over the upper Midwest, but the weather pattern has continued to include frequent and sometimes violent thunderstorms with heavy rain. Rainfall totals for July to date exceed 5-6 inches in many locations in northern and central Illinois (see July summary table below), and flooding rains fell again on northwestern Indiana. The week ahead looks to be dry (finally!) and should continue to be much cooler than normal. Last year we suffered through 15 days in July with high temps in the 90s, and July was almost two degrees warmer than normal; this year we may have as few as 7-10 days of 90+ heat and finish well below the normal temperature range. Dig it! Diseases: We have had very few reports of disease activity since the heat and humidity left town. We have observed some Rhizoctonia patch/ring activity on both bentgrass and Poa annua, with a significant amount of this still due to Rhizoctonia zeae, a fall/spring cool season pathogen, as well as R solani, summer warm season pathogen. Patches caused by R. zeae will have a ring of dead leaf tissue sorrounding healthy plants (see photo above), much like fairy rings, while R. solani symptoms are the more typical smoke -ringed completely necrotic patches. Normally, patches caused by these two Rhizoctonia species would not be evident at the same time, but this year, the environmental factors favorable for infection have been close together (hot humid weather in early July followed by cool wet weather later in July). To get more detail on this phenomenon, click here to read "A Wacky Year for Rhizoctonia" from the Ohio State University's SK Turfnotes. Fairy rings and localized dry spot (LDS) continue to be problems for many superintendents - although there should be very few dry spots around after all of this precip! If you see areas on putting greens that look like LDS but are not accompanied by obviously dry soil layers underneath, there are several alternative causes that can be diagnosed with a little extra observation. 1) anthracnose - look for stem base or stolon rot and fungal fruiting bodies in the foliage. 2) black turfgrass ataenius grubs - the affected area will have very shallow or no roots left what-so-ever… dig around! You may be surprised.. 3) nematodes - especially the ones that cause root stunting or swellings (root-knot, lance, cyst, lesion)… 4) bacterial wilt - becoming more common on Poa annua and less common on bentgrass. Insects: The big story besides the cool temps and T-storms has been insect activity. We have seen or heard reports of numerous bugs in the last week or so. For example: black cutworm activity has increased again, perhaps the second of three possible generations appearing. Also, sod webworm larvae are making their silk lined sand tunnels on our untreated test plots - birds are pecking away at these as well as the cutworms. Ataenius grubs are causing scattered damage, including a few greens that were attacked on the south side last week. Japanese beetle adults have been observed with increasing frequency, but overall it appears that the infestation may be much less than in years past (or maybe just LATER) - we will see. We have also observed some mild damage on Poa fairways from a billbug/weevil grub, which is another insect that feeds on lower stems and roots. Finally, we have seen some serious defoliation of a group of small crabapple trees by bagworms (see photos above) - which is one of the weirder insects - little dunce caps with worms inside crawling around on the tree trunks and flying through the air on fine strands of silk. For more information on these critters see this link to the UIUC Home Yard and Garden newsletter. Weeds: A few different summer broad leaf and annual grassy weeds are starting to appear in low maintenance or stressed/weakened turf. These include purslane, oxalis, spotted spurge, and grasses such as crabgrass, goosegrass, and foxtails, plus yellow nutsedge. We have them all here at Golf House! We don't have any moss in our greens yet, though - cutting heights haven't become an issue yet with the "members!" +++++++++++++++++++++++ Thanks for your support of this, as well as all of our research programs, Randy Kane CDGA Director of Turfgrass Programs Midwest Golf House 11855 Archer Ave Lemont, IL 60439 630-257-8126 Lee Miller CDGA Manager of Turfgrass Research Midwest Golf House 11855 Archer Ave Lemont, IL 60439 630-257-2005 x.111 Summary of IT data for July City or Town Rain from 7/1 - 7/23 Recent Pest Predictions (color level & dates) Degree days St. Louis* 3.53 inches Brown Patch (yellow: 7/16,19,20, orange: 7/17) Pythium (orange: 7/17) Japanese Beetle grubs (red: 7/13 - ) 2,110 Peoria 5.56 inches Brown Patch (yellow: 7/17, 21) Pythium (7/15, 17) Japanese Beetle adults (orange: 7/16-22) 1756 Rock Island 3.93 inches Brown Patch (orange: 7/10 - 18, 7/20 - 22) Pythium (orange: 7/15) Japanese beetle adults (orange: 7/19 - 22) 1,669 Orland Park 4.76 inches Brown Patch (orange: 7/17, 21) Japanese beetle adults (yellow: 7/4 - 7/8) 1,485 Aurora 8.09 inches Brown Patch (orange: 7/15, 21, red: 7/17, 20) Japanese beetle adults (yellow: 7/7 - 12) 1,400 Elmhurst 3.53 inches Brown Patch (yellow: 7/15, 21) Japanese beetle adults (yellow: 7/9 - 14) 1,340 Naperville 5.38 inches Brown Patch (orange: 7/15, 17, 21-22, red: 7/20) Japanese beetle adults (yellow: 7/10 - 15) 1.305 Cary 3.09 inches Brown Patch (yellow: 7/15, 17) Japanese beetle adults (7/11 - 7/16) 1,295 Libertyville 4.17 inches Brown Patch (orange: 7/15-7/17, 7/21) Japanese beetle adults (yellow: 7/16 - 21) 1,175 N. Barrington 3.25 inches Brown Patch (orange: 7/15, 17, 20 - 21) Japanese beetle adults (yellow: 7/20 - 22) 1,104