Issue 9, June 20, 2016

Herbicide Drift

The weather is finally warm (almost hot) and the planters are rolling full speed across central Illinois. Gardens are being planted as well. Planting preparation in farm fields often includes the use of herbicides to kill off any unwanted weeds that have set up residence this spring. Invasive species and other miscellaneous weeds in non-crop areas are being sprayed as well. 'Tis the season for much growth, and much death of plants. We humans are kind of funny like that.

Speaking of death, the curled, yellowed, and necrotic spotted leaves have started to arrive at the U of I Plant Clinic. Puzzle pieces then have to be put together to determine if nearby pesticide (often herbicide) applications are possibly to blame for the injured plants that are dead, yellowed, curled, etc. Of course environmental conditions, diseases, and insect problems can mimic these symptoms which makes a proper diagnosis especially challenging.

Herbicide drift on viburnum.

Couple this with all the different herbicides and various plants we have gracing our Illinois landscape and things can get complicated quickly. Then factor in the unknowns such as not knowing when a neighbor sprayed, what they sprayed or even if they sprayed.

The process has been likened by us as being "CSI for Plants". We are easily entertained you think, but at least we are enthusiastic about what we do. "CSI – Urbana". I like that.

Prevention of this unwanted pesticide injury to your plants is certainly important. It makes things the easiest for all involved. The reality is that pesticide applications are going to happen across Illinois this summer. Producers, landscapers, and others have crops, lawns, and other investments to protect from weeds, insects, and diseases.

Herbicide drift on apple.

If you are a grower of a sensitive crop, build good relations with your neighbors and ask them for advance notice when they spray. By law and depending on the type of application, they may not be required to give you notice. But, most are willing to provide this information if asked. Most applicators will do everything possible to prevent off target movement of pesticides. However, wind gusts and sudden changes in wind direction can occur. Talking with your neighbors is the FIRST step towards preventing drift. Applicators, please do everything in your power to keep your applications on target.

A helpful publication on this topic is "Reducing Pesticide Drift: Specialty Crops and Conventional Crops as Good Neighbors". It can be viewed at:
Also available is an online training module that includes information and helpful tips on preventing and dealing with the off-target movement of herbicide applications. "Herbicide Tolerant Crop Stewardship" is available for free at:

Additionally, if you have a particularly sensitive crop or area that must be protected from pesticide drift, let neighboring applicators know about it. Commercial crop producers can register their sites at (part of FieldWatch, Inc.), which is an online registry designed to help pesticide applicators, specialty crop growers, and stewards of at-risk habitats communicate more effectively to protect pesticide-sensitive areas. Sensitive crop areas registered on this site include beehives, certified organic crops, fruits, grapes, nursery crops, pumpkins, melons, tomatoes, and vegetables.

If apparent herbicide damage is present, the applicator and owner should meet to talk about the injury symptoms being shown and what possible causes there are. Consider when the symptoms first appeared and when the application was made.

What pesticide was applied? Is there a pattern to the injury? Are many species showing symptoms or is it only one plant in a group of similar plants? What have the weather conditions been and what were they like at the time of application? Is the applicator willing to pay for damages or replace dead plants? It is often faster, easier, and cheaper to settle these disputes without legal involvement.

Compare what you are seeing to other plants. What does herbicide injury look like on landscape plants? Check out some pictures at Search by problem and then type in "herbicide". The pictures were the result of some U of I demonstration plots.

You can send affected plant samples to the University of Illinois Plant Clinic. For information on how to do so, go to Be sure to include as much relevant information as possible. Keep in mind that the Plant Clinic does not perform pesticide residue tests, and without such tests, the cause of a symptom cannot be attributed to pesticide drift with 100% certainty. However, it is possible for Clinic staff and specialists to rule out other possible causes and establish whether the likely cause is drift.

If you choose to file a complaint with IDA, time is of the essence. The pesticide drift complaint process is started by calling IDA's Bureau of Environmental Programs at 1-800-641-3934 (voice and TDD) or 217-785-2427 for a complaint form.

Complaint forms must be received by IDA within 30 days of the incident or within 30 days of when the damage was first noticed. Complaints filed after that will be kept on record, but no administrative action can be taken.

Once a complaint is filed with the department, a field inspector is assigned the case. In most cases, the inspector will interview the complainant and inspect the site. Various types of samples, such as plants, water, or soil, may be collected for analysis at an approved laboratory.

The inspector may also interview applicators in the area, examine pesticide records and collect weather data in an attempt to determine the nature and cause of the damage. The field investigator will then submit a report to the Department for review.

Both parties will receive written notification if the Department finds a violation and takes an enforcement action. Penalties range from advisory or warning letters to monetary penalties of $750 to $10,000, depending on the type and severity of the violation. Penalties are determined through a point system defined in the Illinois Pesticide Act.

Even if a violation of the Illinois Pesticide Act cannot be substantiated, both the complainant and the alleged violator will be notified in writing of the complaint's status. Remember, the Department's role in pesticide misuse incidents is limited to determining whether a violation has occurred. IDA cannot help complainants recover damages.

The degree to which the plant is affected depends on several factors: the type and amount of chemical applied, the time of year, the growth stage of the plant, overall health of the plant, etc .

The healthier the plant is (adequate moisture and light) the more likely it is to survive. Although adding fertilizer is typically helpful to a stressed plant, fertilizer can also stimulate growth, which can further increase the appearance of abnormal growth caused by certain herbicides.

For more drift resources, check out the University of Illinois Pesticide Safety Education website at: (Michelle Wiesbrook)

Michelle Wiesbrook

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