{"id":125,"date":"2014-06-27T11:33:18","date_gmt":"2014-06-27T15:33:18","guid":{"rendered":"http:\/\/site.extension.uga.edu\/brooksag\/?p=125"},"modified":"2014-06-27T11:33:18","modified_gmt":"2014-06-27T15:33:18","slug":"cotton-pgrs","status":"publish","type":"post","link":"https:\/\/site.extension.uga.edu\/brooksag\/2014\/06\/cotton-pgrs\/","title":{"rendered":"Cotton – PGRs"},"content":{"rendered":"

\"PGR<\/a><\/p>\n

At this point, much of the earlier planted cotton is squaring and it is time to consider our options and \u00a0begin applying plant growth regulators (PGRs). \u00a0I want to share information related to the timing of these applications and various strategies we can use with PGRs. \u00a0First, recalling our objective with the application of PGRs is important. \u00a0We are wanting to decrease the activity of gibberellic acid (a natural plant hormone)\u00a0resulting in a shorter than normal plant.<\/p>\n

The benefits of working with this size cotton plant include;<\/p>\n

1. \u00a0Decrease in lodging, prevent plants from getting to tall with heavy boll load and falling over.<\/p>\n

2. \u00a0Keeping the plant canopy short assists in decreasing boll rot and helps prevent hardlock. \u00a0This positive effect is due to improved drying and air flow to bolls and lint.<\/p>\n

3. \u00a0Improved penetration of all chemicals used.<\/p>\n

4. \u00a0Improves harvests efficiency.<\/p>\n

As you can see, there are numerous benefits with the application of PGRs. \u00a0However, yield response to PGRs is inconsistent. \u00a0Dr. Guy Collins, UGA Cotton agronomist, states that most of the time (65-70% of time) PGRs have no affect on yield. \u00a0Dr. Collins suggest that if you do see a response in yield it is most likely due to indirect effects (increased light penetration, diversion of photosynthates to boll, improved harvests).<\/p>\n

We have three basic choices of products to choose from to help us achieve this overall reduction in plant size.<\/p>\n

1. \u00a0Mepiquat Chloride – 0.35 lbs. of active ingredient\/gl. \u00a0Several trade names available.<\/p>\n

2. \u00a0Pentia – Mepiquat Pentaborate – 0.82 lbs. of active ingredient\/gl. \u00a0Claims to be more rainfast.<\/p>\n

3. \u00a0Stance – Mepiquat Chloride(0.736 lbs. of active ingredient\/gl.) + Cyclanilide (0.184lbs. active ingredient\/gl.) \u00a0The amount of mepiquat chloride in this product is double the amount found in standard mepiquat chloride and will be used at a much lower rate. \u00a0For example, 6.5 oz. use rate of standard mepiquat chloride is equal to 3 oz.use \u00a0rate of Stance. \u00a0The cyclanilide ingredient in this product acts as a synergist to mepiquat chloride.<\/p>\n

When we apply PGRs we are only affecting the upper 9-10 inches of plant. \u00a0Most of the PGR activity will occur in the upper 4-5 nodes providing slow down rate of terminal growth. \u00a0This shortened terminal growth will allow the developing boll load to catch up with new growth.<\/p>\n

The use of PGRs becomes even more important for later planted cotton. \u00a0Later planted cotton would be that cotton that was planted between June 7 – June 15. \u00a0When we are in this later planting window, we really only have a 3-4 week bloom period to make crop. \u00a0So, we need timely PGR applications to improve retention on lower nodes. \u00a0PGRs play a major role in later planted cotton production.<\/p>\n

The environment is going to be the main indicator for the need of PGRs. \u00a0Any conditions that promote rank\/excessive growth will require the application of PGRs. \u00a0I have attached a chart listing relative PGR requirements of cotton varieties. \u00a0This information, developed by Dr. Guy Collins and Dr. Jared Whitaker, is only be used as a tool and to supplement the consideration of current environmental\u00a0conditions and\u00a0information available.<\/p>\n

\"Whitaker-and-Collins-PGR-Variety-Chart-2014\"<\/a>(Click to enlarge)<\/p>\n

I want to list a few plant measurement options to help determine when to apply PGRs. \u00a0Dr. Collins suggest to keep in mind the overall plant size relative to where it is in bloom period. \u00a0At the end of the season, UGA recommends\u00a0that ideally we would like to see,\u00a0no cotton less than 36″ tall and no cotton more than 50-55″ tall. \u00a0This cotton plant height range is tall enough to support good boll load but not too tall that it results in negative effects produced by rank cotton.<\/p>\n

PGR Plant Measurement Tools:<\/p>\n

1. \u00a0Consider current plant height relative to target end season plant height.<\/p>\n

2. \u00a0Nodes above white flower, if greater than 9 or 10 nodes, consider slowing the plant down with PGR application.<\/p>\n

3. \u00a0Internode distance near plant terminal provides us the cotton plant’s current growth rate. \u00a0This is the best indicator of current plant growth. \u00a0Look between 4-5 true leaf if we have 3″ or more of growth consider PGR application.<\/p>\n

\"PGR<\/a><\/p>\n

4. \u00a0Height to node ratio. \u00a0But, this doesn’t measure current growth rates only assesses overall growth rate.<\/p>\n

5. \u00a0Fruit retention.<\/p>\n

Once you have determined the need for PGR application, you have three basic application strategies. \u00a0It is important to remember that timeliness of application is more important than rate. \u00a0We can achieve more growth suppression by being timely than by using higher rates.<\/p>\n

1. \u00a0Low Rate, Multiple Applications – Make 3 to 4 applications of low PGR rates @ 6-8 oz. \u00a0This application technique begins at first square and is reapplied every 10-14 days until first bloom.<\/p>\n

2. \u00a0Modified Early Bloom – Make 2 to 3 applications of moderate PGR rates @ 8-10 oz., beginning at 8-10 leaf stage. \u00a0This is usually followed by another application at first bloom and if needed at mid bloom. \u00a0Rates will go up as plant size increases.<\/p>\n

3. \u00a0Early Bloom – Make 1 to 2 applications of high PGR rates @ first bloom. \u00a0A mid bloom application is necessary in some situations. \u00a0Use caution when applying this strategy, especially in early maturing varieties and in dryland situations. \u00a0We do not want to force pre-mature cut out with applications of PGRs while plant is under stressed conditions. \u00a0If cotton appears wilted no PGRs are necessary. \u00a0The sun and dry weather are conducting all plant growth regulation needed.<\/p>\n

There is no one PGR plan that works for every situation. \u00a0PGR decisions have to made on a case by case and field by field evaluation strategy.<\/p>\n","protected":false},"excerpt":{"rendered":"

At this point, much of the earlier planted cotton is squaring and it is time to consider our options and \u00a0begin applying plant growth regulators (PGRs). \u00a0I want to share information related to the timing of these applications and various strategies we can use with PGRs. \u00a0First, recalling our objective with the application of PGRs […]<\/p>\n","protected":false},"author":40,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-125","post","type-post","status-publish","format-standard","hentry","category-cotton"],"_links":{"self":[{"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/posts\/125","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/users\/40"}],"replies":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/comments?post=125"}],"version-history":[{"count":12,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/posts\/125\/revisions"}],"predecessor-version":[{"id":143,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/posts\/125\/revisions\/143"}],"wp:attachment":[{"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/media?parent=125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/categories?post=125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/brooksag\/wp-json\/wp\/v2\/tags?post=125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}