Weathering This Unusual Growing Season: Field Days Offer Answers

Record-setting rainfall is the talk of the Valley as we continue to see some wild weather and yo-yoing temperatures. It’s turning out to be a short season for cotton growers. How should growers approach their crop this summer?. Well, there will several opportunities in the coming week to ask questions and learn what to do this season from top cotton experts.

On Thursday, I will participate in our Cotton Pest Management Field Day from 10 a.m. to noon at the Bettencourt Farm in Mendota. The featured speakers: Dr. Pete Goodell of University of California Statewide Integrated Pest Management at the Kearney Ag Center on managing lygus and Dan Munk, UC Cooperative Extension farm advisor and cotton specialist, on plant development and its role in IPM. Check our Sustainable Cotton Project website for directions.

 The following week on Wednesday July 6, there will be two Cotton Production Meetings focusing on making realistic crop, nitrogen and water management decisions in a short season. Growers can attend either one. The presenters include Dan Munk, UC Statewide cotton specialist Bob Hutmacher, UCCE Tulare and Kings counties farm advisor Steve Wright and UC extension entomologist Larry Godfrey.

The first session will be from 8 to 9:15 a.m. at the Comfort Inn, 10 N. Irwin St., Hanford. Breakfast and registration begins at 7:15 a.m.

The second session will be from 10:30 a.m. to noon at the West Side Research and Education Center, 17353 W. Oakland Ave., Five Points. A lunch will follow. For more information, call Steve Wright (559) 684-3315 or Dan Munk (559) 456-7561.

Bring your questions to these free events. See you there.

Cotton: The Case of the Missing First Squares

As I travel around the Valley, I’ve been noticing an unusual trend in many cotton fields.

The plants are at the seventh or eighth node, or true leaf, and showing the first pinhead squares. In all my years of scouting, though, I’ve never found so many first squares missing on young cotton plants. The first square location is important and can impact profits in the long run.  Losing the first square position causes the plant to become more vegetative and experience problems retaining fruit.

   I’m seeing missing first squares in 20 to 30 percent of the cotton fields that I’m scouting this season. In the past, the highest rate 5 to 10 percent of the fields.

   The squares are nibbled off by pests we had this spring. The growing      season is eight to 10 days behind schedule.

   Some growers irrigated too soon and ended up lowering the soil     temperature, which affected plant development. UC IPM is a good resource to learn about monitoring early squaring in cotton growth and development.

   Of course, this plant condition is worrisome to growers. Some might be tempted to apply growth regulators such as Pix, which are designed to increase boll retention and cut back vegetative growth.  Regulators can reduce yields if applied when plants are going through stressful, especially moisture-related, conditions. They also can lead to stunted plants, which could prompt growers to increase nitrogen into the soil to help the plants grow taller for easier harvest in the fall.

Determine the reasons why the first squares are missing. Some pest control advisors might want to start treating for lygus now.

Remember to keep monitoring the fields for pest pressures and be familiar with the surrounding fields. If you’re growing safflower nearby, you might want to treat it for lygus. If you have alfalfa, let borders or strips to prevent migration of worms and lygus. You could treat the alfalfa strips rather than the cotton field.

Lacewings are natural enemy to aphids.

Meanwhile, I’ve spotted some aphids in the cotton fields. Natural predators such as ladybugs and lacewings could take care of small problems. Spot treatment is another alternative.

I am starting a weekly release of 10,000 to 15,000 lacewings for each field I’m scouting to control the aphids.

Field Day Alert: I will participate in our Cotton Pest Management Field Day on Thursday, June 30 from 10 a.m. to noon at the Bettencourt Farm in Mendota. The featured speakers: Dr. Pete Goodell of University of California Statewide Integrated Pest Management at the Kearney Ag Center on managing lygus and Dan Munk, UC Cooperative Extension farm advisor and cotton specialist, on plant development and its role in IPM. Check our Sustainable Cotton Project website for directions. It’s sure to be extremely informative and give growers an opportunity to meet cotton experts directly.

                        

Butterflies a Warning Sign for Alfalfa Growers

Alfalfa caterpillar butterflies.

Photo buffs might get a thrill taking snapshots of colorful yellow and white butterflies fluttering around amber fields of alfalfa.

Growers, though, might get a chill when they spot dozens of these insects in their fields. It’s a warning sign that alfalfa caterpillar populations are on the rise.

Sweep the net in a 180-degree arc.

With summer around the corner, I’m starting to see an increase in worms around Valley alfalfa fields as growers prepare to cut their crop for the third time this season. If left unchecked, caterpillars and armyworms can eat away a grower’s profits as they feed on leaves and stems and defoliate the crop.

I can’t stress it enough: Monitoring your fields pays off. It’s a smart way to manage pest threats effectively and economically while helping you determine when to schedule treatment. In the long run, you avoid unnecessary treatments and save money because your decisions are based on need instead of the calendar.

 As soon as caterpillars are spotted in the field, you can use this as a warning sign and begin regular sweeping for alfalfa caterpillars, western yellowstriped armyworms and beet armyworms. 

To make the task easier, the University of California Statewide Integrated Pest Management program offers a monitoring form (100 kb pdf) to record your observations and tips about sampling with a sweep net. The monitoring form includes treatment thresholds.

Here’s a summary of alfalfa caterpillar and armyworm monitoring guidelines from UC IPM: With a sweep net 15 inches in diameter, you should take weekly samples in fields where plants are at least plants 6- to 10-inches tall. Divide each field into four sections and take five sweeps per area – for a total of 20 sweeps. Lets confirm that these are taken from the site correctly.

Western yellowstriped armyworm larva.

After finishing your sweeps, identify, count and record the number of healthy and parasitized caterpillars (caterpillars with fatal parasitic wasps living in them) caught in the net. Then you divide the total by the number of sweeps. Use the monitoring form to list the average number per sweep. Here’s how you determine a parasitized caterpillar: Pull apart young worms (at least a half-inch long) and see if a white or green parasitic wasp larvae comes out. Population estimates are based on the average taken in a field, counting only armyworms that are at least a half-inch long.

Full-grown alfalfa caterpillar.
UC IPM photos by Jack Kelly Clark

If you’re not scheduled to cut soon after monitoring, you should follow these guidelines for scheduling treatment:

• An average of 10 or more nonparasitized alfalfa caterpillars per sweep.
• An average of 15 or more nonparasitized armyworms per sweep.
• An average of a combined 10 or more nonparasitized alfalfa caterpillars and armyworms per sweep.

Be sure to talk to your pest control advisor about organic and or targeted reduced risk materials that won’t harm beneficial insects or the environment.

Patience a Virtue When Scheduling First Irrigation of Cotton

Mother Nature is sure taking us on a roller coaster ride in the San Joaquin Valley. It’s warm and sunny one day. Cool and rainy the next.

The unseasonably cool and wet weather lately has left cotton growers sitting on the sidelines, anxiously waiting to irrigate their young crop for the first time this season. Normally, the first irrigation comes around the end of May or the first week of June. This year, the first irrigation might be 7 to 10 days later than usual.

My advice to growers: Be patient. Scheduling your first irrigation too early could hurt you in the “bucket” at harvest time. Watering too soon will lower the soil temperature by 3 to 8 degrees and slow plant development and growth. It can lead to vegetative plants using up valuable nutrients and make it difficult to manage the crop. In the long, this translates into lower yields in the fall.

Looking at the 10-year average, we should be seeing 6 to 8 true leaves or nodes this time of the year. Today, I’m seeing plants at 4 to 5 true leaves, with some showing the 6^th leaf.

University of California researchers indicate the proper timing of the first irrigation is crucial and can boost yields by up to 400 pounds per acre. Air temperatures, wind and plant root development are among the factors that go into the decision.

As a general rule, growers schedule the first irrigation when moisture in the soil is six inches from the top. Currently, I’m finding moisture at 4 to 5 inches deep. We’re close to the irrigation threshold, but not there yet. We'll have to see what the impact will be from the rainfall over the weekend.

Bob Hutmacher, University of California at Davis statewide cotton specialist, reminds us this spring’s roller coaster weather requires growers to be vigilant about monitoring soil moisture and assessing root development in making irrigation decisions. A good ’ol shovel comes handy for monitoring, he says. To read about crop conditions and irrigation decisions, download a pdf (64.7 kb) of Bob’s recent Cotton Field Check publication.

Ants Are Out on a Limb in Almond Orchards

Editor’s note: This week’s post is written by guest blogger Kevin Parkinson, almond field scout for the San Joaquin Sustainable Farming Project.

Most of us know by now that ants can cause significant damage to almond crops once the nuts have been shaken to the ground (see “The Almond Doctor” May 2, 2010). But something that many do not realize is that ants may begin to be a problem at hull split if the lower limbs of the almond tree are touching the ground.

Photos by UC Statewide IPM Program.

 If your limbs are touching the ground at this point in the season or you have a history of ant damage, the best thing you can do is monitor for ants following the guidelines of the University of California Statewide Integrated Pest Management program for ants in almonds and treat if necessary.

Result of ant damage in almonds.

To prevent ants from climbing limbs in future seasons, make sure limbs are pruned high enough off of the ground to prevent them from touching the ground with a full crop of almonds.  Remember: Ants do not climb up the trunks of almond trees.  If you have ants attacking nuts while still in the tree, they are climbing up limbs that are touching the ground.

On a final note, you should know that not all ants are bad.  Many are beneficial.  Check out this guide to help you identify common ants found in almond orchards.