This project provided strategic leadership for pest management and resistance stewardship across the cotton industry whilst also conducting research to better understand the relationship between early season fruit retention and the pursuit of very high yields. Key project outcomes were: 

• A successful campaign was conducted during the summer of 2019/20 to inform advisors and growers throughout the industry that drought conditions could significantly alter accepted silverleaf whitefly (SLW) management paradigms for honeydew lint contamination. This campaign involved various stakeholders (ginners, marketers & researchers) who collectively gave timely updates across the industry for locations spanning Griffith to Mungindi about the need for more stringent SLW management. Messages presented at these meetings were reinforced by newsletters, videos and online forums with the CCA to ensure the rapid dissemination of updated information for SLW management under dry conditions. Consequently, SLW were well managed across the industry with no reports of sticky cotton. 

• Numerous extension products (videos, newsletters and industry articles) and services (field walks, workshops, training and formal presentations) were created and provided to industry during this project. This extension was strategic with the purpose of encouraging longer term change for pest management practices across the industry as well as responsive to emerging issues (e.g. lint stickiness and locusts) each season. 

• A survey of Cotton Pest Management Guide (CPMG) users identified opportunities for content improvement. As a result, changes include a foldout chemical guideline, new images and re-written chapter sections. A range of resources that compliment the CPMG have been created including CottonInfo YouTube videos, an updated SLW management guideline and relevant responsive newsletters. 

The impacts of early season square loss on the growth, yield and quality of commercial irrigated Bollgard® 3 cotton was investigated at numerous locations spanning Emerald to Leeton. The ability of Bollgard® 3 varieties to compensate for early season square loss was high with no impact on yield and quality except for one research site (Leeton). Compensation occurred primarily through retention of bolls on more distal FB positions (>P2) immediately adjacent to lost positions. Consequently, crop maturity was minimally affected but the pattern of boll opening was altered (which may change defoliation commencement timing). For warmer regions north of Narrabri, the ability to rapidly compensate reinforces that square loss within the previously recommended range of 60-70% is inconsequential for yield potential, with experimental damage treatments far exceeding these levels without negative impact for yield, lint quality and final crop maturity. However, the results at Leeton and Whitton suggest caution is required for far southern sites and a need for additional replication across seasons and fields to better understand the circumstances and potential frequency under which suboptimal results arising from poor retention may occur. 

NOTE that this work is ongoing and therefore recommendations for industry practice for managing early season retention cannot be provided at this stage.