Welcome to our Ag Blog. Our field scouts will offer a unique ground-level perspective from the field to you as an independent field scout with the San Joaquin Sustainable Farming Project. Our mission is to promote sustainable farming systems throughout the Central Valley and provide you with the latest information about cotton, almond and alfalfa crops. From time to time, you'll also find guest posts from our project team and other contributors. This Blog is produced by Gilbert Mohtes-Chan.
Monday, July 2, 2012
Patience Can Pay Off When Making Treatment Decisions
It’s a familiar scene: You’re stopped at a busy intersection
and another driver pulls next to you and starts revving up his engine like a
wannabe drag racer. Trying to time the signal, he punches the gas pedal and
speeds through the intersection – before the light turns green.
Lately, I’ve seen a few cotton growers resemble over-eager
drivers. They seemed to be jumping the
gun on treating their fields for lygus. I believe they could have waited.
This is where using a sweep net to take pest samples and plant
mapping to measure fruit retention becomes an important tool in the treatment
decision-making process. I wholeheartedly agree with this advice from UC IPM:
“If retention is higher than expected you may be able to wait and monitor again
that week before making a treatment decision. If retention is lower than
expected and lygus bugs are present, consider treating.” To read more about
this topic, here’s a link to the lygus pest management guidelines.
- UC IPM graphics
As I tell growers, cotton plants can’t hold all their fruit
and it’s normal to lose a certain amount. My rule of thumb is to hold off on
treatment for a fruit retention rate above 80 percent. The treatment threshold comes
into play when the rate falls below 80 percent retention, especially for Pima
varieties which have small bolls.
A cotton boll in pre-bloom.
I saw one field being treated even though fruit retention
was at 85 to 90 percent. When you’re above the 80 percent threshold, you should
continue monitoring your field and taking pest samples. You may see lygus
counts drop because the bugs are heading off to more preferred conditions in nearby alfalfa fields.
By jumping the gun, growers could impact the ecological
balance by harming natural predators which play a big part in using biological
controls to managing crop-threatening pests. Besides, beneficial insects are
good for the pocketbook as well as the environment. Using softer materials can help
preserve the beneficial insect population.
Alfalfa is drying around an uncut strip.
In the alfalfa fields, growers are cutting their crop for
the third time this season. Some already are preparing for the fourth cutting,
irrigating the fields and adding a bit of fertilizer to spur growth. Remember
to keep leaving strips of uncut alfalfa to keep lygus from migrating to nearby
cotton fields. Be a good neighbor.
I’m seeing an increase in worm activity. So far, there no
signs of growers treating their alfalfa for worms. Remember to keep monitoring
Looking ahead, July will be another busy month with little
time to rest – even on the Fourth of July holiday this Wednesday. Like farmers
around here, Independence Day is another work day for Valley agriculture.
Wishing everyone an enjoyable Fourth of July holiday.