Pest Patrol

Texas is using GIS to reduce the boll weevil infestation responsible for destroying billions of dollars worth of crops.

by / April 16, 2002 0
The boll weevil is one of the most destructive pests in American agriculture. A native of Mexico, it first appeared in Brownsville, Texas, around 1892. Since then weevil depredations to U.S. cotton crops have run into the billions of dollars. It was not until the recent decade that federal and state agencies and cotton growers combined forces and brought advanced technology to bear on the problem.
Texas was among the first to adapt geospatial technologies to the monitoring, decision-making and treatment processes involved in cotton production. The need was clear: Cotton is the state's number one cash crop, contributing over $1.3 billion annually to the Texas economy, even after losing 10 percent of crops to weevils each year. Losses would be upward of 20 percent had Texas, the federal government and cotton growers not taken action, according to Carl Anderson, agricultural economist and cotton marketing specialist at the Texas A&M Cooperative Extension Program.
In an effort to banish the weevil once and for all, the State Legislature in 1996 established the Texas Boll Weevil Eradication Foundation (TBWEF), a quasi-government entity funded by cotton growers, the state and the U.S. Department of Agriculture. Since 1999, the Legislature has appropriated $125 million in support of the foundation's eradication program.

Eradication Plans
At the time, TBWEF Program Director Osama El-Lissy, along with others, proposed using geospatial technologies in concert with proven labor-intensive monitoring and treatment methods as a practical approach to large-scale weevil eradication. El-Lissy said a combination of GIS, GPS and advanced database-management technologies could accelerate the foundation's eradication program.
"Based on GIS analysis of predefined biological, meteorological and operational parameters, such a system could indicate which fields to treat and when," El-Lissy said. "If the system is user friendly and practical to integrate into the Boll Weevil Eradication Program, fewer, less-experienced workers will be able to produce the same results as those achieved by many experienced personnel, but faster and more efficiently."

Role of Spatial Technology
In 1996, the TBWEF introduced the Boll Weevil Eradication Expert System (BWEES) to facilitate the eradication program. A GIS-based application developed by El-Lissy and the foundation's IT group, the BWEES incorporates data from a wide range of sources. Differential GPS point files of field coordinates, field shapes, acreage and weevil trap locations are downloaded to MapInfo Pro GIS and integrated into the base map of a cotton field and its surrounding environment. Grower data, planting dates, cotton variety, numbers of weevils found in the traps and related agricultural information are all stored in an Oracle database-management system and integrated into thematic maps of the respective cotton fields.
Trap data are collected with bar code scanners during weekly field inspections. The scanner automatically records date, time and trap number, and prompts the user for the number of weevils in the trap, the growth stage of the crop and related information. Data from the scanners is downloaded to the GIS and linked to the map location of each trap, enabling supervisors and producers to precisely locate weevil infestations in the field.
MapInfo MapX compares this data against parameters established for cotton fields at various stages of crop growth and infestation. Based on the number of weevils caught in traps over time, MapX color-codes fields meeting various growth and treatment criteria. Data on fields marked for treatment are entered into a contractor's DGPS-based flight-tracking system, which is designed to trigger spray only on the infested areas of the field. After treatment, the swath tracks and related data from the aerial applications are incorporated into the BWEES and used to assess the progress of eradication and monitor the health of the field.
The foundation has also Web-enabled the BWEES. Cotton producers can now query a TBWEF site to find out if weevils are present in their fields, where they were trapped, the degree of infestation and progress toward treatment and eradication. The same network links program offices across the state. Supervisors can query eradication operations in any part the state. They can look at trap and field data for specific fields, and plot the migration and population densities of weevils.
El-Lissy said the ability to produce data in near real time allows managers to carry out the eradication program more efficiently. "Timely information on weevil populations, and on when and how much to spray translate to lower production costs for producers," he said.
TBWEF Executive Director Lindy Patton estimates that eradicating the boll weevil from all eleven cotton-growing zones in Texas will cost about $600 million. "Growers will be paying 70 percent to 75 percent of that; the state, probably 15 percent to 20 percent; and the federal government, probably 10 percent," he said. "Of course, those numbers can change, depending on what Congress and the State Legislature decide, and on the available funding."
Patton said the BWEES has already helped lower the cost of the eradication program for producers and the state.
Brian Murray, Texas Department of Agriculture special assistant of producer relations, said "Elimination of the boll weevil means we will no longer need to appropriate eradication funds on the scale we have seen since 1999." He stresses that the goal is eradication. "We hope that one day this job is completed."

Assessing Results
Anderson said the weevil eradication program is spreading rapidly in the production zones across Texas. "I believe some zones, such as San Angelo, have already been declared essentially boll weevil free," he said.
Since initial development of the program, the BWEES capabilities have also been adapted to weevil eradication in other cotton-growing states. Already developed is a special module for eradicating another cotton pest, the pink bollworm. The TBWEF has also helped train cotton producers and agriculture departments in several states on the eradication program and the use of the BWEES. They include Arizona, New Mexico, Arkansas, Oklahoma, parts of Louisiana and Georgia. El-Lissy, who now heads up the USDA's National Cotton Pest Program, said only minor adjustments are required to adapt the BWEES to the eradication of other agricultural pests, such as the Mediterranean fruit fly, citrus canker, etc. "The system can accommodate all of the biological, meteorological and operational parameters necessary for any of these applications," said El-Lissy.

Prognosis
The BWEES has proven highly effective in automating many of the monitoring, administrative and decision-making processes involved in boll weevil eradication. Anderson pointed out that as the program expands, it will result in other benefits as well. "For example, we know that in the long run this program is going to reduce the amount of insecticides currently used. It's also going to reduce the need to employ as many people as we have now. It takes a lot of people to check traps in every cotton field, conduct spraying operations and carry out administrative tasks. As the severity of the infestation diminishes, there will be no need to spray every acre or to employ as many people. It is pretty clear that regions without this program will not be able to compete very well with other regions in the state or with other states that have adopted it."
Susan Combs, Texas commissioner of agriculture, said the program has made eradication an achievable goal. "With 21st century technology and the hard work and commitment of Texas cotton producers and the Texas Boll Weevil Eradication Foundation Inc., we are beginning to win the war on one of the most devastating pests in American agriculture. We have already declared one zone to be functionally eradicated of boll weevils. Doubters are becoming supporters."