I’ve been asked by a few growers “Why is my cotton growing so slowly?”
The answer is primarily cold temperatures. The table below shows how many days are usually required to get from one stage to another. Notice emergence to first square usually takes 27 to 38 days. The difference between these is how warm or cold temperatures are. SOURCE
I planted a cotton variety trial in Austwell, TX on March 12, or 47 days ago. Today this test is at 6-7 true leaf and I am finding a few squares in the plots. The reason for this delay can be seen in the second table. Since planting, only 504 heat units have accumulated.
Based on the heat unit accumulation in this table, the latest planted cotton I would expect to find squares is fields that emerged before March 22. The way this year has been, I wouldn’t be surprised if March 15th planted cotton is not squaring yet. My Calhoun County Cotton was planted on March 26 and averages 4 true-leaves.
Plant maturity is important in pest management. Cotton is susceptible to insects at different times or maturities.
Early season damage windows and the primary insect pests are as follows:
- Emergence to 4-5 leaf – Thrips
- 1st square to bloom – Cotton Fleahopper
- Bloom to cutout – Bollworms and Stink Bugs
Outside of these times, thrips and cotton fleahoppers rarely if ever cause economic damage. In other words, prior to squaring spraying to control cotton fleahopper has not been found to increase grower profits.
Don’t make these unnecessary applications. Save it for squaring cotton.