The contest will consist of four major events plus a mystery event. Inclement weather may delay the contest; however, it will continue as soon as conditions permit.

This contest (in 2026) will be hosted over 2-days therefore coaches may be taken to the contest site to review all aspects of the contest after the students have completed the contest. Coaches will be able to review the six phases of the contest: weed identification, herbicide identification, sprayer and written calibration, crop/weed situation and recommendations, and mystery event. During the event, the host has requested the coaches aid in grading and/or judging as needed.  A committee meeting will also be conducted, if needed, either the day before the contest or on the day of the contest.

1. Weed Identification (100 points)

From the contest weed identification list of 100 weeds and weed seeds/tubers, the host will pick a total of 50 weeds and/or weed seeds to be identified. Plants could either be grown in a field, weed nursery, or pots or presented in digital picture form (must be of good quality and clarity) and may be in any stage of growth or development within reason. A complete weed identification list is provided with the correct spelling of each species (Table 1). Students will be responsible for the correct common and scientific name and spelling (WSSA Composite List of Weeds). All answers must be printed (no cursive allowed) and must be legible to be awarded credit for correct answers. Undergraduate students will only use common names. The fall preceding the contest the host should evaluate its weed seed supply and obtain additional seeds/tubers if needed so that an excellent representation of the weed species can be selected for identification. It is important to utilize as many plant species as possible. The plants will be grown in sufficient numbers so that adequate samples are available so that 30 to 70 contestants can have specimens for identification. The contestants will be allowed ample time to identify each specimen. The percentage of samples will range from 75 to 90% weeds and from 10 to 25% seeds. Uncontaminated samples are essential for effective identification. Pure samples are essential. The contestant’s score will be figured as follows: 2 points for each correctly identified species (1 point for common name and 1 point for scientific name with 0.5 points for genus and 0.5 points for species) x 50 = 100 points. If names are not spelled correctly or capitalized correctly, they are wrong. Likewise, answers must be in the correct column. Teams will not be supplied with weed seeds for studying but rather rely on their own training resources.  However, teams are encouraged to expand/improve their training resources through contact with other weed scientists. This approach may better reflect individual and team preparation for the contest.  There will be a tie breaker question/specimen for weed identification to prevent ties.  It will not be included in the contest score and only be used in the instance of a tie.

2. Calibration (100 points)

This event consists of two sections: an individual written test worth 50 points and a team sprayer calibration event worth 50 points.

The individual written test will cover problems and factual information about sprayer and seed treatment calibration of all types; the written portion will be scored as an individual and team event (50 points per person). The host should take particular care to ensure all banded application and skip-row calibration problems are stated clearly. Individual team members and alternates will be given a maximum of 1 hour to complete the written exam. The host will provide calculators and students will not be allowed to use their own. The three or four individual team member scores will be added and divided by the number of individuals on the team to give the number of points out of 50 for the team score.

In the team section, the host will provide a hands-on calibration activity that focuses on team, rather than individual performance. Students should have practical calibration knowledge for air blast sprayers, tractor sprayers, backpack sprayers, granular applicators, greenhouse spray chambers, etc. Differences in time for the competition will count no more than 40% of the overall score. Accuracy of calibration is critical.

To determine final team score for the calibration event, the number of points scored out of 50 obtained in the team event will be added to the average score of the three or four high team members from the individual calibration problems for a maximum possible of 100 points. 

Reference material includes various Weed Science textbooks, Herbicide Handbook, and various unit conversions.

3. Herbicide Identification (100 points)

This is an area of extreme difficulty for the students. Thus, the host must have available a sprinkler irrigation system so that residual herbicides may be activated and weeds and crops maintained in an active growth stage for postemergence treatments. A list of possible crops and herbicides with rate and method of application are provided in Table 2. The test must contain at least 6 crops and 6 weeds and will be planted and treated with a wide range of preemergence and postemergence herbicides from the list. Each herbicide plot will contain a 1X rate of the unknown herbicide. It is suggested that the test be planted 3 to 5 weeks prior to the contest, with postemergence herbicides being applied 4 to 14 days prior to the contest. Each contestant will be required to identify the unknown herbicides by the WSSA group number and common name by observation of crop and weed responses. Both names and group numbers will be given equal credit; in other words, missing common name or group number will behalfright.

There should be from 10 to 15 plots. Herbicide plots may be duplicated, and check plots can be utilized. It would be of great benefit to the students if they could be led back through the plots following the event. Students will not be allowed to pull any portion of the plants in the plots. If plants are pulled, the student will lose the points for the event.

4. Crop/weed Situation and Recommendations (100 points)

Contestants will be required within 15 minutes to determine and evaluate a crop/weed situation and recommend the most effective legal remedy to the problem. Each contestant will have two field problems to solve. Contestants will all have the same two farmer problems. Recommendations must comply with the label of each herbicide recommended. Students should consider such factors as stage of growth, crop tolerance, climatological factors, agricultural spraying procedures, weed control, economics, and impact upon the environment. The host will determine the best answer considering all alternatives for a situation, although several possible answers may be correct. The latest Federal (Section 3) or State (Section 24C) labels of the product constitutes legal control. The event will be conducted as a “role-play” situation, and the potential problem will be in one of the crops on the problem-solving sheet. Also, the crop/weed situation will involve only the listed herbicides and weeds on the predetermined problem-solving sheet. The contestant will be asked to assume the role of a chemical company representative, state extension specialist, or independent crop consultant when dealing with the farmer and scored as follows:

5 points – proper approach/greeting to farmer

20 points – understanding and solving the problem(s)

12.5 points – recommendations for this year’s crop

12.5 points – recommendations for next year’s crop

Each team will be divided at random into two groups in order to handle one of two different problem situations. Following completion of the first problem, the groups will switch problems and repeat the procedure. Each graduate level contestant will evaluate the same two problems.  If possible, undergraduate contestants could compete in a farmer problem.  This will be decided by the host once team names are submitted on July 4, 2026. Alternates and other individuals will be equally divided between the two groups. The assigned judge and farmer will independently score each participant from a predetermined scoring sheet with assigned points for each statement, compare scores, and adjust if necessary. Prior to the contest, judges and farmers will be tested to ensure that the scorers will give equivalent scores within each individual field problem. Each field problem will be worth 50 points and to obtain the participants’ score, the two scores will be added for a maximum of 100 points.

5. Mystery Event (15 points)

This team or individual event will be an agronomic related problem and the contestants will not be advised of the area to study prior to the contest. The mystery event will count toward the team score and individual scores.