TechNotes May 6 - Preemergent Activity, Soil Temps

PREENERGENTS STILL WORKING. With the relatively cold wet weather that has occurred the last few weeks, the question arises what effect has this weather had on pre-emergent herbicide applications?  Little, if any, detrimental affect has occurred to the pre-emergent herbicide during this cold wet period.  The rainfall that has occurred so far as not moved the herbicide out of the weed germination zone.  The cool temperatures have kept soil temperatures low reducing soil microbial activity.  With lower soil microbial activity there is less microbial breakdown of the herbicide molecule occurring.   If a pre-emergent herbicide was applied prior to the cold snap and prior to annual grass germination, the product should still be effective.

SOIL TEMPERATURES.

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