Plant pests and invasive species
Control and eradicate pests, diseases, and invasive species threatening the agriculture industry
Whether it's pests destroying your crops or invasive plants crowding out native species, we have information to help with prevention, control, and eradication.
Here are the final reports from the 2022 surveys.
Invasive species and pests
In 1992 the Boll Weevil Eradication Law (R.S. 3:1601-1617) was established, authorizing the creation of the Boll Weevil Eradication Commission and clearing the way for a grower referendum to fund the Boll Weevil Eradication Program. The Commission was charged with oversight of the Eradication Program. Grower assessments, State funding, and Federal in-kind services provided the funding necessary to implement the Eradication Program, which began in the Red River Valley and stretched into Northeast Louisiana two years later. The program utilized a combination of field trapping and electronic technology in daily operations, gathering cotton field data using GPS units and overlaying that data onto a computerized mapping program. Weevil trap counts were monitored in each field, recorded with barcode readers, and transmitted electronically. Aerial applicators were required to use DGPS systems with printout capabilities for tracking pesticide applications.
As the program progressed, boll weevil trap captures dropped from 4 to 5 weevils per acre to only a handful of weevils per 1000 acres. In May 2010, the last boll weevil was trapped in the state, and in March 2012, the boll weevil was declared eradicated from the state of Louisiana. The Eradication Program is now at a maintenance level, funded through grower maintenance inspection fees. Traps are placed and monitored according to an approved trapping protocol. Cotton producers have seen increases in yields along with a reduction in the cost of insect control.
Citrus canker ( Xanthomonas axonopodis pv. citri ) is a bacterium that causes lesions on the leaves, stems, and fruit of citrus plants. Lesions have raised, brown, water-soaked margins, usually with a yellow halo. It spreads by wind-driven rain (storms) and on infected equipment. Citrus canker causes leaves and fruit to drop prematurely; infected fruit has an unattractive appearance but is safe to eat.
Citrus Canker Quarantine Map - The following parishes are quarantined for Citrus Canker: Jefferson, Lafourche, Orleans, Plaquemines, St. Bernard, St. Charles, St. James, St. John, and a portion of St. Martin.
Citrus greening ( Candidatus Liberibacter asiaticus ) is a bacterial disease of citrus that is spread through grafting and is transmitted by a tiny insect called an Asian Citrus Psyllid. Citrus Greening does not spread through rain or equipment. The disease was first found in Florida in 2005; in 2008, it also was found at limited sites in Louisiana. Symptoms include leaf mottling that often ignores the leaf veins. New leaves may show symptoms resembling zinc deficiency; older leaves have green, asymmetrical mottling. Other symptoms are yellow shoots, twig die-back, poor flowering, and stunting. Fruit is inedible (sour), small, poorly colored, and/or lopsided.
Citrus Greening Map - The following parishes are quarantined for Citrus Greening: Jefferson, Orleans, Plaquemines, St. Bernard, St. Charles, and Washington.
Asian Citrus Psyllid
Asian Citrus Psyllid ( Diaphorina citri Kuwayama ) is a small insect resembling a tiny cicada that feeds on the sap of citrus and related species, including orange jasmine. It is a known vector that transmits citrus greening disease. ACP eggs are laid on flush growth citrus leaves; there are five nymphal stages that feed on the plant sap and remain fairly stationary; adults are very small (~3mm, 1/8”) and can jump and fly but tend to move only short distances (1/4 mile) and may live two months or more. The real concern regarding Asian Citrus Psyllid is the citrus greening disease the insect transmits.
Asian Citrus Psyllid Quarantine Map - The following parishes are quarantined for Asian Citrus Psyllid: Jefferson, Orleans, Lafourche, Plaquemines, St. Bernard, St. Charles, St. James, St. Tammany, Tangipahoa, and Terrebonne.
In order to reduce the risk of citrus nursery stock being moved from a quarantined area, the LDAF has added a new labeling regulation.
Any citrus nursery stock that is sold or moved into a parish that is quarantined must have a label attached to the plant or container with the following statement: " Prohibited from movement outside of the citrus quarantine areas - Penalty for violation, Louisiana Department of Agriculture and Forestry .")
The labeling requirement is only for the Citrus Canker and Citrus Greening Quarantines. It is not required for the Asian Citrus Psyllid Quarantine.
To avoid confusion with the citrus quarantines, a good rule thumb is to purchase citrus nursery stock from the parish in which you plan to grow it.
A picture of the label is below.
Cogongrass is an extremely destructive invasive species we must control and monitor to help preserve our forest and pastureland. If we stay aggressive with the treatment and continue to inform landowners about this pest, we can make tremendous progress and minimize its effects on our state.
Our Office of Forestry implemented the Cogongrass Treatment Program in the fall of 2018. This program aims to control cogongrass ( Imperata cylindrica ), which is an invasive plant species from Japan. It was introduced in the U.S. through the Port of Mobile in the early 1900s and has since spread throughout the southeastern United States. Cogongrass is considered one of the world’s top 10 worst weeds, according to the Global Invasive Species Database. Cogongrass establishes very easily and replaces native vegetation. Cogongrass also presents a fire hazard due to the temperature at which it burns, has little nutritional value, irritates the mouths of livestock, and creates a monoculture that is unfavorable to wildlife.
Cogongrass is currently known to occur in at least nine parishes, primarily in the Florida Parishes. We have enrolled over 230 landowners in six parishes in the treatment program. In 2021, LDAF treated 1,429 spots for a total of 248 acres.
We investigate any suspected infestations and continue to educate the public about this invasive species. We also continue to enroll landowners in our program.
If you suspect that you have cogongrass, call LDAF at 225-922-1234.
About Emerald Ash Borers
Emerald Ash Borers ( Agrilus planipennis ) is an invasive insect pest native to eastern Russia, China, Korea, and Japan. They did not appear in North America until around 2002, but since then, they have spread across eastern and central North America from Quebec to Tennessee. As the name implies, they prey mainly on Ash trees, which they destroy by eating the water and nutrient-conducting tissues under the tree's bark.
Spotting an infested tree
The first sign that Emerald Ash Borers have infested a tree is when the tree's "canopy" - the dense bunches of leaves that grow on its branches above ground level - grows thin and sparse. This happens because Ash Borers have destroyed the wood fibers that move water and soil nutrients from the tree's roots to its upper branches.
Feral swine are present in all 64 Louisiana parishes and have become a nuisance for landowners and farmers. An ongoing effort to eradicate feral swine on private lands has led to many abatement efforts, including aerial gunning, trapping, and hunting. Though the efforts are being maintained, it is estimated that over 70% of the feral swine population must be eradicated to gain control.
Through partnerships with private entities and state and federal agencies, Soil and Water Conservation Districts (SWCDs) are working with private landowners to assist in the eradication of feral swine. For more information on professional trap system rentals, contact your SWCD .
About Giant Salvinia
Giant salvinia, Salvinia molesta, is a floating aquatic fern found in lakes, ponds, and reservoirs throughout Louisiana. Giant salvinia forms dense mats on the water's surface that can clog waterways, decrease oxygen levels in the water, and displace native species. Commonly confused with common salvinia, giant salvinia can be correctly identified by determining the shape of the leaf hairs.
Eradication techniques vary from mechanical removal to chemical control and biological control. Currently, the LSU AgCenter maintains a biocontrol program for giant salvinia by mass-rearing weevil-infested giant salvinia in outdoor ponds similar to crawfish ponds. Ponds are managed year-round and harvested in the spring or fall once infestation rates are high enough for distribution.
Through an ongoing partnership, the LSU AgCenter and LDAF Office of Soil and Water Conservation (OSWC) and Louisiana Soil and Water Conservation Districts (SWCDs) assist landowners in acquiring salvinia weevils for distribution.
Landowners interested in receiving salvinia weevils can contact the LSU AgCenter for more information.
Guava root-knot nematode (Meloidogyne enterolobii) is a highly pathogenic and invasive nematode species.