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Resistan is a mechanistic simulation model of the process of selection of fungicide-resistant
biotypes of a hypothetical fungal pathogen of a hypothetical crop. The fungus is a polycyclic
organism with many generations per season. There is no genetic component in this simulator.
Reproduction is assumed to be asexual. A small proportion of the initial inoculum is designated
as the fungicide-resistant biotype at the start of the season, and the response of that
population to various fungicide spray programs is observed as the season progresses.
General Instructions
In order for the simulation to run on your computer, your browser must be Java-enabled.
For a free download of the necessary software and the installation instructions, go to
http://www.java.com/en/download/manual.jsp.
Click the Start Simulation
button to the left. The simulation opens in a new window,
across the top of which is a menu bar. Check each menu and note the
selections in each. The menu at the far right is a Help menu
that gives you an explanation of each command and menu selection.
There is also context-sensitive help for each menu item.
The simulation behaves somewhat differently with different browsers and from one
computer to the next. If the model does not load fully on the first try, close it and
open it again. If the scrollbar just below the graph does not appear, increase the
resolution of your monitor and/or enlarge the simulation window. If the help window
will not appear, check to see that the browser's popup blocker is turned off for this application.
You can select up to four fungicides for use during each simulated season
by choosing Select... from the Fungicides menu. By selecting
Schedules..., you can set the dates and doses of fungicide applications.
Begin execution of the simulation by selecting Begin New from the
Simulation menu.
For a detailed description of how the simulation works and how the model is
constructed, see the Resistan Model Description.
....proceed to Getting Started
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Introduction
One of the problems arising from the intensive use of fungicides is the selection
of biotypes of the target fungus that are resistant to the fungicides being used.
This is particularly a problem with the new systemic fungicides with specific,
single-site biochemical modes of action.
The only sure way to avoid problems with fungicide resistance is to avoid using fungicides,
or at least avoid using those fungicides that are "vulnerable" to fungicide resistance.
There are important reasons for using these fungicides, however, so avoiding their use
is not a satisfactory solution to the problem of resistance. The alternative is to learn to
manage the resistance and to obtain maximum
benefit from the fungicide without selecting a fungus population with a high frequency
of resistance.
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Arneson, P. A. 2005. Selection of Fungicide Resistance: Simulation with Resistan. The Plant Health Instructor. DOI:10.1094/PHI/A-2005-0720-01.
Resistan was
first written in Fortran by Phil A. Arneson in 1980 for use as an interactive
learning exercise on a main-frame computer. Three years later, with the
growing use of microcomputers in the classroom, it was adapted to run under
DOS on an IBM PC, still with the line-commands and the line-by-line output.
In 1988 Barr E. Ticknor rewrote the program in "C" to create a menu-driven
version with graphical output for DOS. In 1992 Arneson and Ticknor teamed
up to rewrite Resistan
as a Microsoft Windows application. It was rewritten into Java and modified
as a web application in 2002 by Joshua M. Goldfarb.
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