UGA Cotton Team Newsletter May 2022

Articles in this month’s issue include:

  1. Early Season Growth and Canopy Development (John Snider, Gurpreet Virk, Ved Parkash, and Camp Hand)
  2. Herbicides and Dusting in Cotton can be a Mighty Challenge! (Stanley Culpepper)
  3. In-field Planter Considerations (Simer Virk and Wes Porter)
  4. Weather and Climate Outlook for May 2022 and Beyond (Pam Knox)
  5. Early Season Irrigation Requirements for Cotton Production (Wes Porter, David Hall, and Jason Mallard)
  6. General Thoughts and Last Minute Decisions (Camp Hand)
  7. Early Season Disease and Nematode Update (Bob Kemerait)
  8. When to Spray Thrips (Phillip Roberts)
  9. Your Weed Management Toolbox is in Trouble; Are You Paying Attention? (Stanley Culpepper)

Early Season Growth and Canopy Development (John Snider, Gurpreet Virk, Ved Parkash, and Camp Hand): The previous newsletter covered the different processes occurring during germination and emergence and some important factors affecting stand establishment. Post-emergence, cotton is well-known to have poor seedling vigor compared to other major row crops such as peanuts, corn, and soybean. One of the main reasons for slow early season growth is that cotton has smaller sized seeds with fewer energy reserves compared to the aforementioned crops. Another reason is that true leaves must develop after emergence from an undifferentiated region called the epicotyl, whereas some other crops have their first true leaves present at emergence. Another cause of slow early season shoot growth is higher plant investment in root growth during early development. For example, by the time the cotyledons have unfolded, the tap root may be up to 10 inches deep, and root growth will continue rapidly until flowering. At the onset of flowering, the plant redirects more of its resources to boll production, drastically slowing or even halting root growth altogether. Similar to germination and emergence, early season growth temperatures also impact root growth and early season canopy development. Therefore, it is important to minimize stress in the early season to maximize root growth and promote vigorous canopy development. Figure 1 (A) shows the effect of two different day night temperature regimes- optimal (86/68 °F) and suboptimal (68/59 °F), on root and shoot growth in cotton. Sub-optimal growth conditions can result in reduced root growth along with substantial inhibition of leaf area development. Figure 1 (B) below shows the relationship between average leaf area per plant and total root length per plant at two weeks after planting. Healthy roots are positively associated with healthy shoots. [READ MORE]