Entomology and Pest Management

 Mapping Pest Populations

Last Updated: July 26, 2018

​GIS mapping allows us to better target our pesticide treatments or other intervention strategies so we can put our efforts where they are the most productive.

What is GIS?

GIS is an acronym for Geographic Information Systems. What does this phrase mean? Information systems help us manage what we know by making it easier to organize, store, access, retrieve, manipulate, synthesize, and apply the information to our benefit. Geographic, describes where events, activities, and things happen or exist on the face of the earth. This is a broad definition, and well it should be, because GIS is many different things to many different people.

General Uses for GIS
  • It can be used to simply create maps so that the “where” is clearly described.
  • It can be used to analyze data and relate it to other natural phenomena.
  • It can be used to take advantage of the tremendous amount of information presented by remote sensed data from aerial photography and satellites.
Entomological Uses for GIS
  • Map insect populations so we know where they are and are not so we can work more efficiently and achieve enhanced control with reduced effort.
  • Accurately calculate the area we need to treat so we can mix just the pesticide we need.
  • Identify other natural parameters which predict pest populations. Using parameters which have already been mapped or can be mapped using remote sensed platforms can reduce our in the field surveillance efforts.
  • Relate risk information to others.
Necessary hardware and software

To effectively employ GIS for pest management, tools are needed for both the field and office.

Requirements for georeferencing data

The key to utilizing GIS is to know, with some degree of accuracy, where you are on the face of the earth, where your data was collected from, and how to navigate to specific areas of the earth. Advances in just the last decade have made this task so much easier, and there are many systems on the market to choose from. Contact us for recommendations when purchasing a system. 

Requirements for producing pest maps

Some GIS Terms

Layers – GIS produces maps using layers. It is helpful to think of these as clear sheets with a specific type of information on them. For instance the first layer of a map may be an outline of the land, the second waterways, followed by a road layer and a building layer. In GIS programs layers can be turned on and off and their properties such as color and symbology, modified.

Projections – In order to represent the round earth on a flat surface it is necessary to project the image of the earth. Over the years many projections have been developed to do this. There are two key points the GIS novice should be aware of. First, they should collect all their data using Lat/Long decimal degrees, and Datum WGS1984. Second, they should have a GIS professional assist them in setting up their GIS project and map and insure that all the base layers have been converted to the same projection.

Remote Sensed Data – Remote sensed data is information that has been collected without a human standing at a given point and making and recording an observation. There are many types of remote sensed data available today such as airplane and satellite based photography using many different spectrums, and various types of radar. Resolution of 1 meter or better is readily available and with this data it is possible to determine species of vegetation, soil moisture, surface permeability, wetlands, water and soil temperature, to name just a few. Remote sensing has two advantages, these platforms can see things humans can’t, such as light in the nonvisible spectrum, and such data collection is much less expensive than sending people in to record information.

GIS Helpful Links

There is a wealth of information available on the web about GIS, how to use it, and where to get data, following are a few sites which provide a more detailed overview:

The Value of Mapping Pests

Maps have been critical to mankind’s successes. Frequently “where” is as important, or more important, than “what.” Maps best answer the question of where and allow us to store and pass this information to others. The amount, quality, and detail of information which can be mapped have increased dramatically over just the last few decades. Here are some of the benefits of mapping pest populations.

Better targeting for pesticide treatments

Mapping allows us to better target our pesticide treatments or other intervention strategies so we can put our efforts where they are the most productive. Generally, we have found that 80% of a pest population is located on just 20% to 30% of an area of interest. Being able to identify where the pest is and is not located allows us to achieve enhanced control with reduced effort.

The following case studies show how we have used mapping, to great benefit, for pest management purposes.

Developing pest population predictions

Mapping allows us to develop pest population predictions based on other landscape characteristics such as vegetation and soils. One of the great advantages of entering your data into a Geographic Information System is that you can take advantage of the tremendous amount of knowledge that is already known and routinely tracked regarding the earth’s surface. The amount of detail known about the earth's surface is incredible and continually increasing. For instance, vegetation type, soil type, slope, streams and wetlands, and rainfall amounts are mapped in some detail for the entire United States. Learning the relationship between a pest and the mapped landscape features can significantly reduce the amount of field work necessary to assess, avoid, or control populations.

The following are pest population prediction examples.

Improved risk communication

Mapping allows us to better communicate risk with the general public. The tick threat map developed for the Boy Scout Jamboree is an example. By looking at the map, the public can see where they are, where they are going, and the relative risk of encountering ticks. We believe a map such as this heightens awareness of the risk and results in more use of personal protective measures, since the scouts could see that they would in fact be entering a high risk area for ticks.

Preserving knowledge

Mapping allows us to preserve knowledge so future workers can take advantage of what is already known about the environment. Pest management personnel construct their own mental maps through years of surveys. The problem is that when they move on the new person must then start out with a blank map and do considerable work to relearn what their predecessor had spent so much time learning. By having access to mapped observations which illustrate where pests are most likely to occur, individuals new to an area can save a tremendous amount of surveillance work.

How the APHC Can Help

We offer several avenues of support to help you get started and be successful.

  • We provide suggestions on hardware and software.
  • We provide 1 – 2 day training classes on field referencing data and setting up your project.
  • We provide on site assistance in implementing your GIS and assist in determining the most efficacious sampling plan and analysis tools for your pest.

The APHC GIS Branch is another valuable resource.

  • They provide training, troubleshooting, and a help desk for ESRI’s ArcGIS software products.
  • They assist in obtaining imagery and processing it so it is compatible with your project.
  • Contact information for the APHC GIS Branch can be obtained by calling the toll free number for the Army Public Health Center

Related Army Public Health Center Programs