Southwest Plains IPM report

September 27, 2017

by Tyler Mays, Texas AgriLife Extension Agent, IPM

Harvest time is among us, as a few fields in Gaines County have been dug and harvested and multiple farmers around the area are talking about starting to defoliate their cotton crops. Pivots have run longer than normal thanks to the temperatures being in the upper 90s the last two weeks. Rain is predicted for most of next week, and this has made farmers change plans of digging peanuts to avoid needing to pay for mechanical drying. Cotton around the area ranges from almost ready to defoliate to just now opening bolls. The earlier cotton that is ready to be defoliated is on either dryland, or under limited irrigation that has not received much rain over the year.

Cotton defoliation is among us, and unless fields have already been defoliated, this rain should not lead to many issues, but excess green tender tissue on the top of the plant and may a delay in getting into the field when expected. There has been a lot of talk about producers getting ready to defoliate cotton fields around the area.

Over the last few days I have also received calls on optimum harvest aid application timing, I use two recommendations either when 60-70% of harvestable bolls are open, or when there are 4 or fewer Nodes Above the Uppermost Cracked Boll.

Both recommended times to not always occur at the same time, therefore when making the decision when to spray one should also take into consideration of future weather predictions, crop condition, and the amount of harvestable fruit on the plant that still needs to open. When getting ready to defoliate cotton, below are a list of considerations that should be used to help decide application time and chemical

• Crop Conditions: what type of regrowth do you have?

Terminal regrowth: Can be caused by excessive moisture or nitrogen along with temperatures favorable for growth. Terminal regrowth can be significant if favorable conditions are present after defoliation, and can lead to excess moisture in the module and lead to lint staining. Typically, can be controlled by our normal defoliation products, but removing the leaves are key, as dessicants can sometimes lead to stuck leaves, and lead to reduced lint quality due to leaf fragments not being removed by the ginning process.

Basal Regrowth: Can be caused by diseases such as Verticillium wilt where the plant is defoliated, and allows light to reach the base of the canopy. Basal regrowth can also occur after defoliation if weather conditions favorable for growth occurs after the crop has been defoliated. Basal regrowth can be controlled by products such as Tribufos or PPO defoliants, and/or thidiazuron+diuron (Ginstar and Generics). A mixture of thidiazuron and diuron such as Ginstar, Redi-Pik, and other generics are effective at inhibiting potential for basal regrowth.

•    Weather Conditions: Temperature and moisture between the time of defoliation and harvest can also affect harvest aid timing and chemical selection. Rain and warm weather shortly after defoliation can lead to regrowth issues if certain defoliation products are selected, and even lead to lint sting out and lint staining from excessive moisture in the module.

•    Crop Stage: Whether you apply harvest aid at 4 Nodes Above Cracked Boll or at 60-70% open bolls. Keep in mind the time needed for a field to be ready for harvest the quickest a field will be ready for harvest is a minimum of 7 days and as long as about 14 days, depending

•    Yield Potential: Not all fields will be able to afford the top-notch harvest aid. When choosing a harvest aid, look at what product you can afford on a field by field basis.

PEANUTS:

Peanuts harvest has begun on a few fields in Gaines county. Over the last two weeks, I have been pod blasting and boarding peanuts to check for optimum digging time. Fields in Terry and Yoakum have ranged as close as 14 days and as far away as 24 days. Fields in Gaines County that were brought to the pod blasting meeting on the 12th of September were as close as 7 days away from digging and as far away as 14 days from digging. When determining when to dig peanuts there are a few common practices, some of which are not as accurate as others. These common practices include digging based on calendar days since planting, digging when neighbors are starting to dig, the hull scrape method and pod blasting. The most accurate ways are the hull scrape and pod blasting, with pod blasting being the most accurate of the two methods. Hull scraping involves pulling pods out of the ground and scaping the saddle of the peanut to see the color of the mesocarp. Based on the number of pods that are black, brown, and orange one can get an idea of when the optimum time is to dig peanuts. Pod blasting is probably the most accurate method for determining when to dig peanut fields, as maturity can vary based on irrigation capacity, moisture received during growing season, soil type, and farming practices. Pod blasting includes pulling up a sample of 150 to 200 pods per a field and using a pressure washer to expose the pod’s mesocarp. Once the mesocarp of the pods are exposed these peanuts are placed on a peanut maturity profile board, which based on the color of the mesocarp and where the pods line up on the chart determines the estimated days to digging. If pod blasting leads to greater than 10 days a second or even third pod blast should be conducted as weather conditions can slow or speed up the maturity of peanuts.

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Category: Agriculture