Revised Planting Window for Full Season Cototn Varieties

Abstract

A heat-unit-based planting window was introduced in 1991 as a means of reducing early season problems with pink bollworm (PBW). Growers were encouraged to plant full season varieties when the annual heat unit (HU) accumulation ranged between 600 and 900 -- a window designed to ensure 75% suicidal emergence of PBW yet maintain acceptable yield levels. New research findings and a reexamination of past PBW emergence studies now support making an adjustment to the planting window. For 199Z the recommended planting window is 450 - 700 HUs after January 1.