Field Scouts Poised to Help Growers Battle Pests

Cotton fields are planted. Almonds are growing nicely and pest traps are in place. And alfalfa fields are being irrigated after the first cutting of the season.

Yes, everything is progressing well for cotton, almond and alfalfa growers as we prepare to turn the page on another month. In the Valley, May means warmer weather – and pests – are ahead.

“When it heats up bug populations explode,” almond and alfalfa field scout Damien Jelen says.

Once again, Damien and almond field scout Jenna Mayfield are poised to provide another set of eyes to help growers monitor pest populations in their fields and orchards in Fresno, Merced and Madera counties. 

A sweep net snags pests living in an alfalfa field.

They will keep growers informed and updated on field and orchard conditions, providing reports such as fruit retention data to cotton growers and petiole samples for almond growers. Damien and Jenna also are connected to leadingUniversity of California crop experts to stay on top of any problems.

Field scouting offers an economical and environmentally sound way to help growers make timely pest management decisions before major crop damage occurs. Regular scouting also can help prevent unnecessary treatments.

As field scouts, Jenna and Damien make daily rounds around fields and orchards and write up weekly field notes for each grower. Jenna monitors pest traps set up around almond orchards. Damien uses a sweep net to monitor pest levels in cotton and alfalfa. They know where pests live and what the bugs look like and how to count them.

Jenna checks a pest trap during her field scouting rounds.

So far, Jenna has reported on an early uptick in leaffooted plant bugs. Growers have tackled the pest, but it’s hard to tell how much damage this pest has caused until after the harvest.  Jenna says peach twig borer eggs are on her watch list after inspecting traps in the orchards. So far, the numbers aren’t worrisome – for now.

  

In alfalfa, weevil numbers are on the rise but they dropped after the first cutting. Damien expects aphid populations to increase once the weather heats up. But overall pests are under control in alfalfa for now.

Pima: King of California Cotton as Season Begins In the Valley

Despite a little rain and unseasonably cool temperatures last week, cotton growers continued to plant the seeds for the coming season. That meant soil temperatures have reached the perfect threshold for planting this year’s Acala and American Pima crops.

Cotton growers are busy planting their crop this season.

Field scout Damien Jelen estimates about half of growers have planted their crop. The rest will wrap up over the next week. For some early bird growers, they are seeing seedlings already emerging from the ground.

“By April 30^th, everything should be planted in order to make the fall harvest in time,” Damien says.

If growers plant too late, they risk trying to harvest their cotton in less than ideal weather conditions. We all know how nature can be so unpredictable.

For now, we can say let the cotton season begin. Of course, the race to harvest is like a marathon – a slow, lumbering season that lasts 180 to 200 days from seed to cotton bolls.

Seedlings are emerging in some cotton fields.

This year, forecasters are predicting a slight increase of cotton acreage in California – thanks to a boost in planting of the high-end American Pima variety. The USDA National Agricultural Statistics Service forecasts growers will plant82,000 acres of Upland/Acala cotton in the state, a 6.8 percent drop from 2017.

In contrast, Golden State growers, primarily those in the San Joaquin Valley, expect to plant 230,000 acres of Pima, up 7 percent from last year. Once again, California will account for the lion’s share of Pima acreage – 88 percent – planted in the United States.

Nationally, the USDA estimates the planted area for all U.S. cotton in 2018 at 13.5 million acres – a 7% increase over 2017.

It’s easy to say Pima serves as the backbone of California’s cotton industry, which has steadily declined over the decades. The fine, extra-long fiber is dubbed by some as “cashmere of cotton,” rivaling fine Egyptian cotton. It commands a higher price than Acala, which can allow growers to continue growing cotton despite rising water prices.

Pima was introduced to the state in the 1990s. The arid Valley weather was ideal for growing the variety.  Moreover, heavy marketing by the trade group, Supima,sparked demand by textile mills and the fiber eventually became the choice for premium sheets and shirts.

 

Special cotton gins also emerged to gently process Pima to preserve the quality of the fiber. Damien noted a Pima gin opened recently in Dos Palos.  Thanks to Pima, cotton remains relevant in California agriculture.

Something is Already Starting to Bug Almonds This Season

Things are getting a little buggy for almond growers.

That’s not good news, especially this early in the season, reports almond field scout Jenna Mayfield. This concern compounds the trouble already experienced by growers because of the February freeze and March and April rains. Oh yes, we forget to mention the dry December and January weather.

The sun made an appearance in the Valley last week.

“It has been weird. There will be all kinds of crop losses,” Jenna says. But that won’t be known until harvest time.

After a number of growers wrapped up another application of fungicides a week ago Sunday, Jenna had time later in the week to venture into the orchards to inspect the progress of almonds. The nuts are a good size, she says. 

Young almonds are growing nicely.

But she adds:  “Leaffooted plant bugs are out there. Everyone is worried about that.” Jenna says growers are staying vigilant and keeping a close eye for signs of pest damage.

The leaffooted plant bug (LFPB) gets its name because of the leaf-like enlargements found on the hind legs. Adults are about an inch long with a yellow or white zigzag line across its flat back. UC Integrated Pest Management called LFPB a sporadic pest for almonds.

Damage can be significant when weather conditions are right. Here’s what UC IPM says: “Feeding by adult leaffooted bugs on young nuts before the shell hardens causes the embryo to wither or abort or may cause the nut to gum internally, resulting in a bump or gumming on the shell. It can also cause nut drop. After the shell hardens, adult leaffooted bug feeding can still cause black spots on the kernel or wrinkled, misshapen nutmeats.”

Experts say the bugs often show up in April in search of food after overwintering in nearby fields. Jenna noted she usually spots the pest in May. “They seem to be a little early this year.”

Here's a leaffooted plant bug.

Two indicators of LFPB problems are gumming found on the outside of the nut or aborted nuts on the ground. However, there is a seven- to 10- day lag between feeding and when the gumming and nut drop take place. By the time these signs are evident, the pest may have already moved on.

“Treatment thresholds have not been developed for this pest in almonds, but low numbers of bugs can cause substantial damage. If bugs and their damage are evident, consider an insecticide application; apply insecticides through May to target the overwintering adults that have migrated into the orchard," UC IPM says.

You can see the LFPB damage to the almond kernel.

“Unfortunately, the broad-spectrum products that are most effective against leaffooted bugs are also very disruptive to biological control agents of spider mites and other almond pests. Later applications are not needed when numbers of overwintering adults have declined or nymphs are the only life stage present, as their mouthparts are too small to feed on the kernel.”  It’s important for growers to weigh the consequences when they are making an insecticide choice to avoid secondary problems that can flare up after use of broad spectrum materials.

Given the all the weather issues and early pest concerns, growers are pressing on and “hoping for the best,” Jenna says.

Warm April Showers Prompts Growers to Protect Almond Trees from Disease

The Pineapple Express rolled into the Central Valley at the end of last week, delivering warm rain to our region.

Variable weather hit almonds, including a hard freeze.

Like we mentioned last month, this wet stuff during the late winter and early spring continues tobewitch almond growers who are still trying to assess any damage from the freezing weather in February. 

David Doll, a UC Cooperative Extension pomologist and almond expert in Merced County, says the April showers may prompt almond growers to make another fungicide application.

“If a spray has not been made within the last seven to 10 days, consider making a spray with a rotating chemistry to reduce the occurrence of the spring time diseases of Anthracnose, scab and shot-hole. If there is a history of bacterial spot, a copper-manzate application should be considered,” Doll wrote in a recent Almond Doctor online column.

So far this season, Doll has observed cases of leaf lesions caused by bacteria. This condition, which is evident by a yellow halo on the leaf, could be compounded by more rain. Trees eventually recover after losing some leaves.

Almond growers need to protect trees from scale.

On the pest front, Doll recommends growers putting out traps and monitoring for navel orangeworm (NOW).  Orchards with a lot of mummy nuts are likely to need treating for NOW in the spring. Those growers who did a good job with orchard sanitation “are not going to have much value in a spring spray,” Doll told growers attending a recent almond field day.

Meanwhile in the fields, field scout Damien Jelen says the rain has slowed some cotton planting. A lot depends on the soil. Some soil will dry faster and allow growers to get back into the field and finish planting.

Alfalfa growers are finishing the first cutting of the season.

In alfalfa, growers have completed[ their first cutting. Now, Damien says, they are waiting for the cut alfalfa to dry more on the ground before baling the crop.

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