February 25, 2017

1 – Pecan weevil quarantines in New Mexico are limited to the areas where the weevils were found, but New Mexico gardeners should be watching for the weevil in their pecans.

Yard and Garden February 25, 2017

Q.

According to an Associated Press report in the Albuquerque Journal, in January the New Mexico Department of Agriculture imposed a temporary restriction on movement of pecan trees within a few New Mexico cities, including Roswell. Do you have any idea why restrictions are limited to City of Roswell and not encompassing Chaves County? I doubt if the weevils stop at the city limits and there are many residential growers, not just commercial, in Chaves County.

- TJ

Roswell

A.

I contacted Dr. Carol Sutherland, NMSU Extension Entomologist about the pecan quarantine. She provided information about the quarantine and a description of the pecan weevil so other New Mexico gardeners can be watching for it in their gardens. Her reply follows:

Briefly, the current temporary quarantine (60 days) only affects pecan growers within the city limits of Roswell, Artesia, Hobbs, Lovington, and Clovis because that is where the pests were found in nuts from landscape pecan trees in people’s yards.

In at least one of these situations, the homeowner had found ‘little white worms in her pecans’ for several years. After several years she contacted the NMSU Cooperative Extension Service the weevil was identified. This may have happened in the other affected counties also, with either the backyard growers or local pecan buyers suspicious of the damage in local nuts. Either the county agents or the NMDA inspector intercepted these questions and damaged nuts, resulting in a flurry of regulatory activity and the quarantine to keep infested pecan nuts from leaving their points of origin.

The odds of eradicating this most serious pest of pecan nuts in the US are much higher if the pests are confined to limited areas - and those limited areas are identified. Eradication has been done several times before in New Mexico and it has been successful in all of these cases. New Mexico is the only state in the nation that strives to find and eradicate pecan weevil as quickly and efficiently as possible. Elsewhere in the U.S. pecan growers are stuck with managing the pests.

Dr. Sutherland stated “This is still a very ‘fluid situation’ with lots of nuts in people’s yards” so it will be good for homeowners across New Mexico to watch for this pest in their pecans.

The ‘evidence’ of the pecan weevil infestation: “Pecan weevil (larva) emergence holes in pecan shells will be perfectly round and about the diameter of a BB. It is NOT an impact wound made by a bird pecking a hole in the shell. The latter will have an irregular margin, likely with bits of shell punched into the nutmeat.

Pecan weevil larvae are multi-segmented, creamy white, legless grubs with a reddish-brown head capsule and chewing jaws. One or more larvae may be inside a nut. Growers would have to be really ‘lucky’ to see these inside the nut or emerging through the shell.

For a cracked nut with a BB-sized hole through the shell, the nutmeat may be partly or totally consumed by the pecan weevil larvae that used to be inside the nut. Affected nutmeats will often turn black, as may the inside of the shell. Pecan weevil larvae do not produce any silk.

If ANY pecan grower - whether you have one tree or thousands - finds suspect damage like this, put it into a plastic bag and into your freezer right away. Contact your County Extension Agent (every county has one) immediately; they should travel to your location to evaluate your evidence.

For more gardening information, visit the NMSU Extension publications Web site at http://aces.nmsu.edu/pubs/_h, or to read past articles of Yard and Garden go to http://aces.nmsu.edu/pubs/periodicals.html.

Send your gardening questions to Yard and Garden, Attn: Dr. Curtis Smith at cwsmith@nmsu.edu or leave a message at https://www.facebook.com/NMSUExtExpStnPubs.

Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist, retired from New Mexico State University's Cooperative Extension Service. NMSU and the U.S. Department of Agriculture cooperating.