Monday, September 23, 2013

Snorkels, Leaf Blight and Sympathy

That was just not called for.  Nobody ordered that much water.  
Pioneer Sales Rep Kevin Nixon, from Ilderton posted this picture.  With his ears in jeopardy he was ready to order a set of snorkels.

Some have been wondering about the bleached look that took over corn fields last week.  It looks like the crop was frozen, but not all fields look the same. How come?
The answer is it is not frost.  It is Northern Corn Leaf Blight.  It starts out looking like this.
The symptom for NLB is long cigar shaped lesions on the leaf.  NLB is a fungal disease that survives on corn trash and spread by rain and wind.  High humidity, heavy dews and moderate temperatures favour infection levels to increase and it can increase rapidly.
This diagram explains how NLB spreads quickly during the growing season.  Lesions can produce new spores in a week.  This rapid reproduction cycle allows the disease to spread more quickly than most other diseases.
When NLB becomes severe the leaf begins to look grey and "frosted" like the one above. Continuous corn where the previous year's trash is left close to the soil surface is more susceptible.  Hybrids can make a difference too.
I took this picture from a strip plot.  The hybrid on the left P9910XR scores a 4 for NLB resistance.  The hybrid on the right P0094AM scores a 5 for NLB.  Most years a 4 score is more than adequate, but not under heavy pressure.  Plants that have a lot of NLB infection lose photosynthetic capacity due to the reduced effective leaf area.  Test weight will tend to be lower and standability may be affected as well because the plant mobilizes reserves from the stalk in an attempt to fill the ear.

Finally a heart felt sympathy is extended to the volunteers of the International Plowing Match after Mother Nature forced them to cancel the last day of the match on Saturday.
Brian took this shot while going in to assist with the evacuation.  All the long hours of volunteer effort swamped in a sea of mud.  Very sad.  

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