IPM Update – Cotton Growth and Fleahoppers

Cotton maturity ranges from 5-6 leaf to third-grown square.  Continue to scout for cotton fleahoppers, I have fields with more than 40 per 100 plants.  The Economic Threshold is 15 per 100 plants so these field should be treated to prevent square loss.  Some fields or parts of fields are yellowing due to excessive soil moisture making nitrogen less available.  This should be corrected once the soil dries if the field was properly fertilized.

I have had several conversations about the temperatures we have had so far this year.  Some of them start with “Its finally warming up.”  This got me to looking at historical temperatures and what I found was we are experiencing slightly above normal heat unit accumulation.

It is important to note that we have had some cold spells that have delayed some crop maturity.  My calendar shows my cotton should have had its first squares May 1-2.  But I did not see many squares until May 9-10.

Heat Unit Accumulation (DD60s) from date until May 16
HU in 2023 10-year average difference from average
1-Mar 920 669 +251
10-Mar 821 660 +161
20-Mar 757 630 +127
30-Mar 639 578 +60
1-Apr 606 565 +41
10-Apr 515 493 +21
20-Apr 407 391 +16
30-Apr 294 264 +30
10-May 129 116 +13

Plant Growth Regulators are also a topic of discussion.  If you are already planning a herbicide or insecticide application, it is reasonable to add a mepiquat chloride (MC) product at 4-8 oz/A. I would not apply higher rates prior to bloom.  Keep in mind what cotton variety is planted as there is considerable difference in varietal response to MC. Some varieties can be hurt with too much MC at prior to bloom. Others may get away from you if you don’t get the MC into the plant soon.

Monday morning

Crop Scouting Meeting

When: 9 am, Monday, May 22

Where: FM 1679, just south of Sanders Rd.

We will be looking at a new way to scout for cotton fleahoppers.

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