Nothing Beats Low-Tech When It Comes to Mapping Cotton Plants Developing in the Fields

Remember those days when book stores sold street maps and county map books.

  

Baby boomers can still visit AAA and pick up the old-fashioned folding maps. Millennials will snicker and pull out their smart phones tap into their Google Maps, Apple Maps or QuickMap apps.

So far, we haven’t found one for cotton plant mapping. Growers still have to do their mapping the old fashioned way as they keep track of developments in the field to help reap a successful yield at harvest time.

Plant mapping, or monitoring, comes in handy because it allows growers to identify potential problems and better manage their cotton. For example, mapping can aid in the timing of pest management decisions.

Field scout Damien Jelen has been mapping to monitor plant development. He reports fields are showing about 70 percent retention in squares. 

As a rule, there usually is only 25 to 60 percent retention of first position squares on fruiting branches 10 through 12. You start to worry when the first position  square retention on the upper five fruiting branches come in under 80 percent. This could be caused by insect damage or the lack of moisture.

In past, the routine was very labor intensive because it mirrored the detailed plant maps used by researchers, who recorded every fruiting part of the plant. But subsequent studies found gathering numbers for a few sites will produce useful information.

Rather than comb the field, you can go to four areas of a field and measure five plants in each area. The cotton season can be divided into four management periods:

·         From plant emergence to square: This is when you count plant stand and height and the number of nodes. Walk around the field and check for drainage issues, missing rows and pest damage. This information will help with replanting and pest management decisions.

·         From firstsquare to first bloom: In this stage, sample at least five plants in four different sections of the field. Then collect information about plant height, the number of nodes, fruiting branches and square retention. Also record fruit set and growth. This information is important for crunching numbers and guiding decisions on pest control and the possible use of growth regulators. For example, square retention calculations can assist in developing pest management strategies.

·         From first bloom to cut-out: This is the time when the plant becomes larger. You record plant height, number of nodes, nodes above first position white flower and first position squares above the white flower and first position bolls below white flower in the first or second position. This information indicates how the crop is developing and provides insights about vegetative growth and boll development as you approach cut-out – the final stage of plant growth before the bolls open.

·         From Cut-out to defoliation:Measure the plants for boll retention, boll re-growth and boll opening. Noting nodes above cracked boll will help with the decision about the timing of defoliation.

UC IPM offers a wealth of information and tools for cotton growers monitoring cotton plant growth. Perhaps one day some app developer will come up with a cotton plant mapping app.on their website

Meanwhile, on the almond front, field scout Jenna Mayfield reports hulls are starting split in trees on the outside margins of orchards. Mites are starting to show up and a number of growers are starting to apply miticides.

FIELD DAY: Learn about the latest developments in cotton during a 10 a.m. field day  Tuesday at Pik-A-Lok Farms on Bass Avenue in Mendota. Featured speakers  at the free even are:

·         Dr. Pete Goodell, UC Cooperative Extension and UC Statewide Integrated Pest Management emeritus, who will cover pests and pesticides and how to manage the crop for lint yield and quality.

·         Dan Munk, UCCE Fresno County farm advisor and cotton specialist, who will discuss monitoring cotton for improved yield performance.

·         Bob Hutmacher, UCCE extension specialist  of the Westside Research and Extension Center, who will provide an update on Race 4 fusarium in the region, cotton diseases and plant development issues.

Continuing education credits of 1.5 hours have been approved. The field day is sponsored by the San Joaquin Sustainable Farm Project. For more information, contact Project Director Marcia Gibbs at (530) 370-5325.