Answer: Although somewhat unusual, there are several different disease problems such as bacterial blight and verticillium that could cause symptoms similar to what you described. I would suggest you work with your Penn State county extension to obtain a specific diagnosis of the problem and based on knowing that, decide how to treat it.
I don't think the spikes would have caused this, however in general perhaps a more suitable fertilizer would be a spring top dressing with compost and then a general purpose granular or slow release granular fertilizer spread over the surface to provide a more evenly distributed dose of nutrients. You could try that next year.
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