Pest Alerts

August 2014

Pecan weevil alert - read more.

August 2013

Pecan weevil management decision-making is upon us. Note that many pecan growing areas are facing drought conditions.  This may result in drought-delayed emergence well beyond the normal emergence time for this pest, particularly in orchards and groves with clay soils. Read more.

June 2013

A colony of walnut caterpillars.
Walnut caterpillar colony
Walnut caterpillar, 5th instar stage
Walnut caterpillar, 5th instar stage
Walnut caterpillar infestation
Walnut caterpillars on tree


Bill Ree reports walnut caterpillar activity on pecan. Pecan producers or those with urban pecan trees should be watching for this insect. The real damage will occur when the larvae reach the 5th (last) instar. This is the stage when the larvae is black with long white hairs (pictured). These insects can defoliate a tree in 3 - 4 days.

Infestation signs:

  • colonies on branch terminals
  • a mass of cast skins on the main trunk or scaffold limbs
  • a lot of frass on sidewalks or driveways
  • branch terminals with missing foliage but leaf rachis still in tact 

Control options:

  • For homeowners - Bt-based insecticides and products with spinosad (ex: Green Light Lawn and Garden with Spinosad)
  • For commercial producers - Intrepid, Confirm, Belt, Delegate are preferred.
  • For organic producers - Entrust, certified Bt insecticides, Azera and Neemix

August 2012

Pecan weevil alert and new publication.

July 2012

Walnut Sphinx
An outbreak of the walnut sphinx, Amorpha juglandis, was in early July 2012 infesting and defoliating about 100 acres of primarily native orchards between Highway 36 and 1702, south of Gustine, Texas.
Read more and see photos >>>

May 2012

Walnut caterpillars in pecan tree
Photo byHoward Arnett.
Click to enlarge.

Walnut Caterpillar Alert
Producers should be on the lookout for walnut caterpillars starting to lay eggs in the next generation in about 3 weeks and then expect one more generations to occur about 6 weeks after that. Walnut caterpillars have been found as 4th instar larvae and are occurring earlier than usual in Victoria (Victoria County) and Cuero (DeWitt County), Texas.

August 2011

Pecan Weevil Alert
Pecan weevil management decision-making is upon us. Note that many pecan growing areas are facing drought conditions.  This may result in drought-delayed emergence well beyond the normal emergence time for this pest, particularly in orchards and groves with clay soils.
Read more >>>

June 2011

Brown marmorated stinkbug

Brown Marmorated Stinkbug ALERT
A regional pest alert has been issued for the brown marmorated stinkbug. Please see this publication for important information.

August 2010

Pecan Weevil Alert
Pecan weevil management decision-making is already upon us. Note that many pecan growing areas are facing dry conditions, and this may result in drought-delayed emergence well beyond the normal emergence time for this pest, particularly in orchards and groves with clay soils.
Read more >>>

Thousand cankers disease of black walnut reported in Tennessee on July 26, 2010. See companion materials listed below for details. Based on limited research, pecan is not known to be at risk from this disease. Scientists at Colorado State University will provide expert assistance if this disease is suspected present and local scientists should also be informed.

July 2010

Leaf Nutrition Month
July is the time to collect and submit leaf samples for analysis to determine the amount of essential minerals your pecan trees are absorbing from the soil or from foliar treatments. Nitrogen, potassium, zinc and other nutrient deficiencies can be identified from leaf samples.

We have developed an information packet with instructions and locations for submitting leaf samples:
Instructions for Pecan Leaf Sample Collection for Nutritional Analysis [PDF]

June 2010

Walnut Caterpillar Alert
We are observing walnut caterpillar late instar larvae on pecan in Victoria and Cuero, Texas.  Hatch of the next generation at those locations is anticipated to occur about June 25th.

The last couple of years, infestations were observed in Cuero along the Guadalupe River, but so far these have not expanded into an epidemic that defoliates wide expanses of pecans and hickories. Past experience shows walnut caterpillar is capable of widespread defoliation over entire river systems and vigilance is needed to detect them and treat them, if needed, before defoliation occurs.

April 2010

The Pecan IPM PIPE Library is now open!

The Pecan IPM Library offers a wide range of research-based information that can help our constituents make informed decisions about integrated pest management in their pecan operations. Formats include Extension publications, journal articles, newsletters, slide and video presentations and proceedings articles.

January 2010

The Pecan IPM Pesticide search engine is available.

Search the National Agriculture Library's Thesaurus and Glossary from our site. See IPM Resources at the bottom of this page. The Thesaurus and Glossary are online vocabulary tools of agricultural terms in English and Spanish.

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