BATON ROUGE — An executive order signed by Gov. Jeff Landry in response to record-high diesel prices ahead of peak harvest season has placed Louisiana under a state of emergency. The emergency order will allow Louisiana farmers and timber harvesters to use dyed diesel fuel they already have on hand. Dyed diesel is regular diesel fuel that has been dyed red to mark it as off-road fuel; the fuel is also nontaxable. Farmers and loggers buy it for t…