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General View Aug. 5, 2003Our field is still in good shape. The leaves have a nice green color, however, you'd have to admit, the field doesn't look as good as it did when it was in full bloom. But that's what we expect this time of year. The heads continue to droop.  Since August 2nd, we've had about 0.19 inches of rain, but today it was 98 F. 

Head Nodding DownThe heavy heads are causing the stalks to have an extreme bend or crook. That's because the seeds are getting heavier by the day.  Usually, we don't  worry about the stalks breaking, but sometimes when the head is bigger than we like to see and combined with wind, we'll see some stalks will break over.  It will be a while before we see any stalks breaking.


backside of headThe back side of the head or receptacle is losing its green color and it's turning a pale yellow.  The bracts are still green.  This plant is in the R7 stage. It is maturing normally.


RhizopuslesionLet's take a little closer look at a different head. Here we see a brownish lesion. That can't be good . . . and it isn't.  That's damage from head moth larvae as it burrows around in the head.


Cross sectionIf we split the head so that we can see a cross section we can see the seed across the head.  We can also see darker areas across the head. That's head moth larvae damage. Let's look a little closer.


Head moth frassI don't see any head moth larvae.  I know they are there because you can see the brown frass of the larvae.  The sunflower head moth larvae causes damage, but quite often we see a disease called, Rhizopus head rot that's associated with head moth infestations.  The lesion on the back of the head allows disease organisms to enter the head and cause damage.


Early Rhizopus bractsLooking at the bracts around the head we can see brown spots.  Those brown spots could be the early symptoms of Rhizopus head rot. We'll have to watch for that over the next couple weeks.