Tag Archives: Arizona

Cutworms in Alflafa

Ayman Mostafa

There have been many cases of cutworm infestations in alfalfa in central Arizona over the last few weeks. Cutworms are frequent pests in the low desert of Arizona. The granulate (Feltia subterranea) and the variegated (Peridroma saucia) cutworms are the two most common species in alfalfa.

Full grown caterpillars are about 1.5 to 2 inches long and vary in color and patterns. Larvae frequently roll into a C-shape when disturbed. Cutworms feed at night and hide during the day in soil cracks and under debris.

 

Cutworm populations may develop in weedy areas and migrate into seedling or mature stands.

Established fields are damaged when cutworms cut off new growth or feed on the alfalfa foliage. Established alfalfa fields can be severely injured when cutworms cut off new shoots at or below ground level following harvest. The pest often goes undetected after cutting and hay removal but the problem becomes apparent when the field is irrigated and there is little or no regrowth.

Seedling alfalfa stands can be severely damaged by cutworms cutting the seedlings off at or just below the soil surface. Cultural control is important in managing cutworms in alfalfa, especially for new stands. Cutworms are most injurious in fields with high plant residue. Tillage helps to limit cutworm populations; seedlings in well-tilled fields, especially when there is an interval between crops are less likely to have cutworm problems. Keep the field and field edges weed-free. Flood irrigation can drown many cutworm larvae. Flood irrigation during the day will attract many birds that prey on the cutworms as the advancing water forces larvae from hiding. When damage is severe in seedling fields, apply an insecticide bait.

Treatment guidelines have not been established in Arizona. Check for cutworms by looking under duff and carefully digging to a depth of 1 inch in loose soil near alfalfa crowns. When cutworm numbers exceed one or two per foot of row or severe damage is apparent, it may be necessary to treat. If treating with baits, apply baits in late evening or at night when cutworms are on plants.

References:

http://ipm.ucanr.edu/PMG/r1300911.html

Click to access 05-111.pdf

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=10705

Click to access 06-113.pdf

 

Say Stink Bugs

L.M. Brown & P.C. Ellsworth
Recently, high densities of Say Stink Bugs have been reported in Central Arizona. On April 4, Fox News 10 ran a story about “beetles” taking over a Buckeye neighborhood. After a trip to the neighborhood and surrounding areas, we identified them as Say Stink Bug nymphs and concluded that they were coming out of Russian thistle (tumbleweed), which had recently dried down just outside the neighborhood. On April 22, we collected large numbers of Say Stink Bug adults out of a barley field in the Casa Grande area. It is unclear how much damage they cause in small grains; however, they are easily found in wheat and triticale as well. The populations of Say Stink Bug in central Arizona are likely well synchronized this time of year, with most individuals at the same life stage.
http://www.myfoxphoenix.com/story/25169473/2014/04/04/beetle-infestation
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Notes from Your Extension Agent:

“Tent Talks” Meetings: Mark your calendars for the upcoming “Tent Talks” meetings in Central Arizona. The events will run from 7:00 to 10:30 AM

June 26th, 2013 “Tent Talks” meeting will be at A Tumbling T Ranches, Corner of W. Broadway Rd. and S. Estrella Pkwy, Goodyear, AZ 85338
Click Here for the agenda

July 10th, 2013 “Tent Talks” meeting will be at Le Smith’s Farm, Corner of E. Bella Vista Rd. & N. Quail Run Ln, San Tan Valley, AZ 85143
Click Here for the agenda

The meetings will highlight early and in-season agronomic and pest management of field crops.
Presenters include: Paul Brown, Peter Ellsworth, Ms. Shawna Loper, Bill McCloskey, Ayman Mostafa, Randy Norton, Mike Ottman, and Mr. Ron Rayner.
CEUs have been applied for.
An RSVP form for this event can be found under the “Events” page of this website.

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Cotton:

Long term research at the University of Arizona have found that the Upland and Pima cotton varieties grown in Arizona can be tracked over their growth cycle by the use of several simple measures. Plant mapping is a method of measuring cotton growth and reproductive development. Measurements of height to node ratio, fruit retention and nodes above white flower can be correlated to crop management, and yield estimation. As a reminder, members of the UA Extension Ag Team have produced set of short videos demonstrates basic cotton plant structure and plant mapping procedures.

Basic Structure of a Cotton Plant

Estimating the Vegetative/Reproductive Balance in Cotton: I. Height to Node Ratio

Estimating the Vegetative/Reproductive Balance in Cotton – II. Fruit Retention

Estimating the Vegetative/Reproductive Balance in Cotton – III. Nodes Above White Flower

You can find counties/crops advisories at http://ag.arizona.edu/AZMET/az-crop.htm

The hot and dry forecast will ensure high rates of water use in the coming weeks. Water stress at this time of year can reduce plant stature and lead to square abortion. Monitor soil moisture closely and avoid water stress through timely irrigations.