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General view Aug 11, 2003Our field continues to mature.  Kernels are filling (getting bigger). It appears the lower leaves are starting to show
drought symptoms.  We caught a little shower today, but only 0.14 inches. That will hardly settle the dust. 
 

Back of headThe back of this head is more of a buttery-yellow than it was last week. The bracts are still green, but they are
starting to turn yellow too. This plant is in the R8 stage of maturity.  You can see several brown lesions caused by head moth larvae. 


Cross sectionIn this cross section of the head you can see the kernels are developing well, but there are signs of head moth
larvae.   Lets look inside a kernel before we start looking for larvae.


Kernel seedBy opening the hulls you can see the well-shaped, white seed. This seed is developing well, but as it matures it  will turn more gray. 


Larvae peeking outWell, what do we have here? This head moth larva appears to be a little camera shy. 

 


Head moth larvae This is a little better picture of a head moth larva. They have alternating long brown and light stripes. Also, they
have a brown head capsule.  They burrow through the head and damage tissue and seeds.  


Mature Rhizopus headThis is a head near the field edge that has been infected by Rhizopus head rot.  If you didn't see the
neighboring heads that are in the R8 stage, you might think this was a mature head.  This disease can be quite severe resulting in high yield losses.  There's not much a farmer can do about it other than try to control the sunflower head moth.  


Close up Rhizopus headThis is a closer view of the same head.  There's no mistaking that this is a diseased head.  There will be no
harvestable seeds in this head, rather the seeds will be small and shriveled.