Palmer amaranth started emerging in West Tennessee just over the past few days. The first pigweed I noticed emerging was on April 30. This late emergence is very different from past springs. In some years Palmer amaranth has emerged as early as late March. In most years the first Palmer emergence typically occurs in the first week to 10 days of April. From a weed management perspective Palmer amaranth is 3 to 4 weeks late in its arrival.
This is notable from a management perspective in that the April emerging Palmer amaranth is typically removed with the burndown application or tillage. That will not be the case this year for many fields of soybean and cotton. This means that the in-season weed management program will have to control all the potential Palmer amaranth in a given field and not just the second and third wave of emergence.
Palmer is not the only summer annual weed emerging. They all are at this time. Therefore do not forget all the “block and tackle” weed management tactics. The fundamentals of starting clean with tillage or a good burndown, spraying small weeds and utilizing residual herbicides at planting and early post emergence will be very critical in 2018.