In 2014 I planted on Sept 11th and got army worms really bad. Had a 8 day forecast of rains and was heading to Kansas to hunt Mule Deer is why I planted early. Did not get the rains early but got some in late Oct and that is when the worms hit. In 2015 I planted on Oct 4th and got rains on it within 2 weeks. No army worms that year. In 2016 I planted on Sept 13th due to another chance for rain for 10 days. No rain but got some later on into October. Got army worms again but not to bad. In 2017 I had the hurricane moisture and good rain forecast again so I planted on Sept 16th. Oats came up back lack of good follow up rains and heat cause them to not do well till Nov. Got a few army worms also in Oct. I wanted oats up for archery season is why I tried to plant early. If I were planting for hunting deer in South Texas during the rut for rifle season I would not plant till mid October. Heat and moisture would be the two things I would plan to plant around. Army worms have become more of an issue down here than in years past. They even had hit as late as Nov 5th in hotter fall year.
I'm about 35 miles NE of stxranchman and usually plant about the same times he does. I waited a month, because of the armyworms I was seeing and planted 13 acres of oats on October 18. I saw one worm on my windshield while I was planting and thought "crap".
Everything worked out very well, an incredible stand with a lot of seed on the ground with nice flights of morning and whitewing doves. I even mowed it down to no-till native grass seed into the 13 acres but the oats are back up with the cool temperatures. So far, five months of food.
I don't use my food plots for hunting so I don't face the need to get the plants up. I'm going to wait from now on. I also planted another 5 acres with other seeds and it worked out the same. Post rut buck numbers on my place were absolutely crazy. My focus will be hunting very late December & January based on my experience this year.