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Weather Update
The end of May has turned cool and damp, thanks to a slow moving low pressure system ("trough") out of Canada.
The storm was so unusual, it was dubbed the "BIG SPIN" by the meteorologists on the weather channel.
This storm spun around over the upper Midwest for a week or more, bringing cooler temps and intermittent rains/thunder storms that were frequently interrupted by brief views of the sun.
In the Chicago area, we have been about 10 degrees colder than normal since May 24, and had one stretch of nine straight days with measurable precipitation.
The month will end close to normal for average daily temperatures and total rainfall, however.
In central Illinois, the weather picture has been similar, although temperatures have remained a little more moderate (warmish), and not quite as much rain has fallen.
Overnight low temperatures have been consistently in the low to mid 40s, and the high temp most days has been in the mid 60s to mid 70s.
Measurable precipitation has fallen in 8 of the last 12 days, although rainfall amounts still remain low for central Illinois for the 2001 season.
Diseases
Due to the drop in temperatures, late spring disease activity has significantly slowed across most of the northern half of Illinois.
Dollar spot symptoms that were showing up a couple of weeks ago should have subsided for the most part.
If you still have scars from this early outbreak, maybe you should check your fertility levels!?!
Dollar spot could still have some moderate activity in the warmer corridors of central IL, since there have been a few days with temperatures in the upper 70s to low 80s recently.
The cold nights and frequent light rain showers we have experienced in the north are conducive to Microdochium patch (aka Fusarium patch or pink snow mold), so watch out for small, copper colored spots that may expand to the size of a half dollar; don’t mistake this symptom for "copper spot" or "red leaf spot," these are totally unrelated diseases.
Poa annua is more often attacked at this time of year by Microdochium nivale.
If you have a concern about diagnosis, give a call to Hank or myself, or send us a sample of infected leaf tissue to confirm a diagnosis.
We have had a few questions lately about the possible activity (or inactivity) of the patch diseases, such as summer patch on bluegrass and take-all patch on creeping bentgrass.
Since there was a warm and dry stretch of weather earlier in the month, many believe there will be less patch disease activity - since, in general, the pathogens involved are more active root colonizers when soil temperatures are cool and there is ample moisture.
However, our shift back to more spring-like conditions with cooler temperatures and periodic rainfall may stimulate some summer patch symptom development later in the summer.
The prime time for infection by take-all patch fungi (Gaeumannomyces) may have already passed, so there may be little take-all on bent this year.
We will keep you posted if symptoms are reported across the region.
Since there isn’t much action with turf diseases, we thought we would take the opportunity to note a tree disease problem that is fairly new, and some of you may not be familiar with it.
Have you noticed any dying pine trees this spring - aside from the ones along the roadside that get sprayed with salt? There is a vascular wilt disease triggered by a nematode (Y-E-S-S-S!!!) called Bursaphelenchus xylophilus, aka the ‘pine wood nematode.’
Scots pines are the most frequently attacked, although the nematode induced wilt may be found on other species of pine (red and black eg), and other conifers such as spruce.
Early symptoms of the disease are a fading of the green color (wilt), and some yellowing that often quickly leads to brown needles that cling to the tree.
Small trees may wilt and die all at once; sometimes large trees first have symptoms on one or a few branches.
Symptoms may start to show from early summer (eg the last couple of weeks) through early fall.
The nematode is carried by, and introduced into pine wood by the feeding of wood-boring beetles in the family Cerambycidae.
Many of these beetles develop in and feed on diseased trees, pick up the microscopic nematodes, and then move to healthy trees to feed some more.
Diagnosis of this problem is fairly difficult, needless to say, and should be handled by professionals (ie send a sample to a woody plant clinic!)
Insects
The cold weather will slow the movement of winged insects somewhat, but we should be nearing the time of cutworm adults (moths) moving further north and laying eggs.
There have been no reports of serious cutworm larvae activity in northern Illinois to date, nor have there been many reports of adult Ataenius beetles roaming around on greens.
Ants continue their early season mound building activity, and earthworm casts continue to cause problems on fairways.
I have seen another tree-related insect problem in the Chicago area, which appears to be a leaf miner on white birch (or paperbark birch?).
The trees I have seen with this affliction look from a distance like they have been seriously burned (leaf scorch).
Birch leaf miner larvae are small black worms that feed on the tissue between the leaf surfaces and can be seen in the tissue by holding the leaf up to bright light.
The adult leaf miner is a small, black sawfly (3 mm in length).
Females lay eggs on newly emerged leaves only.
If a tree is seriously damaged, new leaves will emerge and these leaves can be infested with a second generation of miners.
Weeds
There is really nothing new to report here, the Poa is still seeding and the moss is still mossing.
We should have some good results of Poa seedhead suppression tests from around the state; we hope to have the web site up and running soon and have some PGR results posted there.
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