Southern  Rolling Plains cotton farmers are on the brink of making the best cotton they’ve had in recent years, thanks to early rainfall that got the crop off to a good start—and in some cases resulted in replanting—and some  August rains that helped finish it out.

Texas AgriLife Extension integrated pest management specialist Rick Minzenmayer, who works Tom Green and Runnells counties, expects to see some two-bale dryland cotton harvested this year. “The crop looks good,” he said during a recent field day on the Wilde farm just outside San Angelo. Cotton is better to the east of San Angelo than to the west, he added.

Seed company representatives on hand to provide updates on new varieties also noted that cotton across the region looks promising as farmers near harvest.

The crop faced challenges and will face more as harvest approaches.

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Doug Wilde, at the field day that’s been an annual event since the early 2000s, said his crop will be “good, overall. We had 14 inches of rain in late May and had to replant some hailed out cotton, including some Pima. June and July turned dry but we got some more rain in August.”

He had just started harvest preparation the last week of September and expected to see some challenges with new growth spurred by September rainfall.

Those late rains likely will create defoliation issues with regrowth. Also, determining the best time to initiate defoliation with immature bolls will require evaluation of whether to risk losing open bolls on the bottom of the plant while waiting for those younger bolls to crack.

Defoliation challenges

“Defoliation will be a challenge with this crop,” Minzenmayer said. “A lot of farmers had just finished their last irrigation when they got a 3-inch to 4-inch rain that stimulated new growth. We hope to find a combination of products that will work well to defoliate this cotton.”

He said a Ginstar and Prep combination and Dropp are good options. “With temperatures at 90 degrees and above Dropp works well.”

Growers may need to increase defoliant rate to get results growers will be looking for.

“Texas AgriLife Extension agronomist David Drake, San Angelo, said timing and thorough coverage will be critical in harvest aid applications.

Drake said farmers have a mish-mash of cotton maturity with “plants that are still blooming and other plants that have shut down.”

A strong recommendation for successful defoliation is to “go back and read the manual, and then go back and read the manual again. We have nothing new,” he said, but he encouraged growers to make certain they were familiar with the products available and the application techniques and timing necessary to get the most yield and best quality out of the crop.

He recommends growers check online instructions at the TAMU cotton website. Then look for harvest aid information.

Determining when the crop is ready to defoliate may seem easy, he said. The general rule is when 60 percent of the bolls are open. It’s a bit more complicated, however. “A lot of variables are at play. Variety and the condition the plants are growing in are also factors.”

The nodes above cracked boll (NACB) option provides a good guide for defoliation. The TAMU guideline reads: “…if the uppermost first position-cracked boll is within three nodes of the uppermost harvestable first position boll then no lint weight will be lost if a defoliant-type harvest aid is applied at that time. However, if the uppermost harvestable first position boll is four or more nodes above the uppermost first position cracked boll, then potential for some lint loss exists. The lint loss potential increases as the NACB increases.

“Micronaire reduction generally follows a similar pattern when using the nodes above cracked boll criterion. When defoliant-type chemicals are applied, some slight subsequent fiber development may occur before defoliation. If applying desiccants, more bolls must be mature in order to reduce the risk of fiber weight loss or reduction of micronaire, thus two to three NACB would be a better target.”

Heat units

Heat units also play an important role, Drake said. A bloom on Sept. 1 would need about 800 heat units to make a harvestable boll into October.

“Some bolls on plants now will not mature,” Drake added. He also recommended the knife test. A sharp knife will cut through an immature boll with little resistance. A mature boll will be almost impossible to cut through.

Because farmers face lower prices they need to harvest every boll they can from this crop but need to weigh potential loss of the bottom bolls as they decide on a defoliation date. “Most of the yield comes from the first bolls.” He also noted that early harvest will affect quality and loan value. “Two to four nodes above cracked boll is a good target,” he said.

Timing also depends on the type of defoliant selected. With a desiccant, producers need to understand that after they spray, the crop is done. “Be certain everything you want to harvest is ready,” before applying a desiccant. He also cautioned growers against defoliating more acreage than they can harvest in a timely manner. He said a PPO defoliant will sometimes “kill the leaf and stick it if you’re not careful.

“Good coverage is necessary,” for successful defoliation, he added. “Use a high volume of water, 10 gallons per acre or more. If the product doesn’t touch the leaves, it will not defoliate. Adequate coverage is essential to get into the canopy.” Drake also advised growers to look back at what they did last year, evaluate products and look at current prices when deciding on defoliants.

The TAMU harvest aid website includes products, by type, and recommended rates. Drake mentioned Aim, Sharpen, ETX, Display Ginstar, and Finish Pro.

Another positive about this crop year, says Wilde, is limited damage from cotton root rot. He and his late father, John, worked with Texas AgriLife Research and Extension for years screening fungicides for root rot control. Topguard is now a routine application for the Wilde farm.

“We saw a little,” he said, “but the summer was dry and we used Topguard on everything so we are not seeing much.”

Others said they’ve seen some root rot in scattered fields. In some cases, those fields were not treated, observers said.

Wilde said he’s also a bit concerned with reniform nematode infestation. He treated some infested fields but would like to see variety resistance. “Most of the nematode resistance work has been for root-knot species,” he said.

Following three straight years of drought-ravaged cotton, Southern Rolling Plains cotton farmers seem willing to put up with the challenges that come with a bit of rain at an inconvenient time. Having extra challenges as they decide on harvest aid procedures is better than having little or no cotton to harvest.