Monday, August 20, 2012

It's Time for Cotton Growers to Bid Farewell to Lygus Worries, Say Hello to Aphid Concerns

 Hello Houston, we’re at cut-out.

More than four months since the seeds were planted, growers are getting a good indication about how much cotton they can bank on at harvest time. Cut-out is the final stage of plant growth before the bolls open. You have mostly mature fruit on the plants and new terminal growth stops taking place.

So, we can pretty much scratch lygus off our list of pests to watch. Of course, we’re far from out of the woods. Now, growers are on aphid watch and their concern (what farmer doesn’t worry) turns to risk of sticky cotton.

Cotton plants are at their final stage of plant growth.
To a lesser extent, Mother Nature has added another thing to worry about – plants stressed by the recent heat wave. In one plot that I’ve scouted, I found cracked bolls. It’s too early for bolls to normally open up. But in this field, the last irrigation came a little early – before the recent parade of triple-digit temperatures, which accelerated the timetable for bolls to open. There’s an interesting article about boll shed and high temperatures in this month’s UC Cooperative Extension Cotton Field Check newsletter.

We can live with more seasonal temperatures in the uppers 90s to 100-degrees. Forget the scorching 110-plus weather. Let’s hope we can stay a little cooler this month.
Growers turn their attention to aphids.
Aphid numbers are up in the fields. I’ve seen some fields treated. Usually, you see higher populations in cotton planted later in the season – around late April. To enhance biological controls, I’ve been releasing beneficial insects – green lacewings – in various fields. They have held back the aphids for a few days. Since the bolls are still closed, I believe growers can be a little more patient and wait a little longer before applying materials. Check UC IPM for more information about aphids in cotton and treatment thresholds.

Green lacewings are released to help control aphids.
Meanwhile, alfalfa growers are finished with their fifth cutting and preparing for the next harvest. They should have two to three more cuttings before wrapping up the season. There have been some worm issues, prompting a few growers to apply treatments. Overall, though, pests have been pretty light.

Our almond field scout Jenna Horine reports pests have been light in the almond orchards in the past week. “That’s good,” she remarked.

Some almond growers already are shaking nuts off the trees.
The harvest varies greatly around here. Some growers are shaking the nuts from the trees. Others are still irrigating their trees with no signs of hullsplit yet. The crop on the westside seems to be maturing faster than the eastside. Soon, she’ll be picking up samples for crack-out to check for pests and help growers develop pest management plans for next season.

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