Our cotton is now progressing 7 – 8 leaves on into squaring. As be begin reproductive growth, we think about irrigation and new insect issues. There are some reports of plants bugs now. If they are not in a field yet, they are hanging out on field edges now in particular flowering plants/weeds.
Although irrigation requirement is higher for blooming cotton than for pre-bloom cotton, stressing cotton during squaring has more negative effects than we realize. Cotton does not rebound if stressed from no irrigation through squaring. UGA Extension Irrigation Specialist Dr. Wes Porter says we have to be careful about losing squares from drought stress. Data on this using the UGA Checkbook Method where pre-bloom irrigation was eliminated found no difference in non-irrigated cotton. The reason for this is that cotton grows vegetatively and reproductively at the same time. During its vegetative growth, cotton is setting nodes. If it is stressed during this time, less nodes are set.
Dr. Porter has been looking at soil moisture sensors and the irrigation apps we can download on our phone. Research does show that the Smart Irrigation App is keeping us from putting out more water than is needed during both drought and rainfall situations. This is interesting because these apps do not monitor soil moisture, and the Smart Irrigation App is no charge to download. We go one step further when we use soil moisture sensors.
Tarnished Plant Bugs
We will now begin scouting for tarnished plant bugs. TPB have piecing/sucking mouthparts (like stinkbugs). Adults have a yellowish triangle behind the thorax with 5 distinct black dots. We want to retain 80% of our squares. Sometimes, less retention can occur even when plant bugs are not present. We need to monitor both square retention and plant bugs. Plant bugs are mobile and can move in and out of fields fast. They can be present and not causing square loss. Here is a threshold from UGA Extension Entomologist Dr. Phillip Roberts:
At cotton scout school this week, Dr. Roberts showed us plant bugs and other insects he is seeing at this time. Colquitt Ag Agent Jenna Brock is seeing some and also some reported by Jodie Stringer down here. I ran a sweep net through one field, and did not see any plants bugs. In a field where I looked, I did find a bigeyed bug. These are not problem insects. They actually feed on small caterpillars and eggs. Minute pirate bugs look somewhat similar and are beneficial also.