Arizona Cooperative Extension generates and distributes weather -based Planting Date and Cotton Development Advisories for 14 cotton production areas (Marana, Laveen, Paloma, Litchfield Pk., Pinal Co., Parker, Mohave Valley, Queen Creek, Safford, Yuma Valley, Aguila, Cochise Co., Greenlee Co. and Harquahala). Planting Date Advisories are distributed from mid -February through the end of April and stress 1) planting cotton varieties according to heat unit accumulations rather than calendar date and 2) the importance of soil temperature to good germination. Cotton Development Advisories are distributed from early May through mid September and provide updates on crop development, insects, weather and agronomy. The Cotton Advisory Program will continue in 1996 and growers may obtain advisories by mail or fax from the local county extension office, and by computer from AZMET or the University of Arizona College of Agriculture World Wide Web Page. Major program changes planned for 1996 include 1) adjusting the Crop Development Advisories to reflect the revised legal first planting dates in low elevation production areas and 2) the addition of an advisory for Harquahala.

Arizona Cooperative Extension generates and distributes weather -based Planting Date and Cotton Development Advisories for 11 cotton production areas (Marana, Laveen, Paloma, Litchfield Pk., Pinal Co., Parker, Mohave Valley, Queen Creek, Safford, Yuma Valley, and Aguila). Planting Date Advisories are distributed from midFebruary through the end of April and stress 1) planting cotton varieties according to heat unit accumulations rather than calendar date and 2) the importance of soil temperature to good germination. Cotton Development Advisories are distributed from early May through mid -September and provide updates on crop development, insects, weather and agronomy. The Cotton Advisory Program will continue in 1994 and growers may obtain the advisories by mail or fax from the local county extension office, and by computer from the AZMET computer bulletin board. Improved normal weather statistics and the addition of an advisory for Cochise County are the main changes planned for the 1995 program. Introduction Arizona Cooperative Extension has published and distributed weekly weather -based advisories for Arizona cotton producers since 1991. This program will again be provided for growers and others in the agribusiness community in 1995. This document briefly reviews the advisory program, then details plans for the 1995 program. Advisory Content The Cotton Advisory Program provides cotton growers weekly updates on crop development, agronomy, pests and weather from mid -February through midSeptember. Two related but distinct advisories are used during the season long program: the Planting Date Advisory and the Cotton Development Advisory. ThePlanting Date Advisory is generated each Monday from mid -February through late April or early May (depending on location) and emphasizes planting cotton in windows defined by heat unit (HU, 86/55 °F thresholds) accumulations rather than calendar dates. The HU windows represent a compromise position between planting early for maximum yield performance and planting late to avoid early season pink bollworm (PBW) infestations. A simple graph showing annual HU accumulation and the desired planting windows is used to illustrate the proper planting time (Figure 1). The remainder of the Planting Date Advisory is devoted to weekly updates on 1) weather conditions (current situation, long -term normals and 5-day forecast), 2) early season pest management, and 3) agronomy. The importance of soil temperature to rapid and uniform germination is stressed in the weekly agronomy updates. Cotton Development Advisories are issued beginning in late April or early May and provide growers information on cotton development, pest management, and season -long crop management (Figure 2). A simple graph tracking HU accumulation for cotton crops planted on four representative planting dates is located at the top of the advisory. HU -based development timelines are used to indicate when growers should expect particular phenological or physiological events such as pinhead square, susceptible square, first flower, cut -out, etc.

RCB with 3 (wheat) or 4 (barley) replications 12/20 & 12/21, 1985 06/09 & 06/10,1986 Wheat 90 lbs. /acre Barley 90 lbs. /acre 12/22/85 5.4 acre /in. 02/08/86 6.0 acre /in. 03/05/86 6.0 acre /in. 03/22/86 3.6 acre /in. 04/09/86 3.24 acre /in. 04/22/86 2.52 acre /in. TOTAL: 26.76 acre /in. 12/18/85 132 lbs. N per acre as NI-13 03/05/86 29 lbs. N per acre as NH3 Cotton None Thimet 20 03/07/86 5 lbs. per acre Wheat 25 x 860 Barley 25 x 800 Wheat Indio Silt Loam, Ripley Silt Loam Barley Meloland Sandy Loam, Holtsville Silt Clay, Indio Silt Loam, Ripley Silt Loam