Issue 9, June 17, 2011

Avoiding and Handling Chemical Injury to Non-target Plants

Well, it is June and the curled and yellowed leaves have started to arrive at the U of I Plant Clinic. Puzzle pieces then have to be put together by me and other diagnosticians 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. 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.

Injury Prevention. 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. If you are a homeowner or perhaps a grower of a sensitive crop, I STRONGLY encourage you to 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. If you are concerned about the health of your plants or maybe that of your family, share your concerns. If you know "what" will be sprayed "when," you can plan accordingly by covering your garden with old blankets, making sure the windows are shut, or keeping the kids out of the yard during that time. I'm not saying drift is permissible. 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. I would discourage you from automatically filing a complaint with the Illinois Department of Agriculture (IDA) when you see the sprayer nearby. Not surprisingly, that is bad for good neighbor relations! You will have your neighbor's attention, but is that the type of attention you are looking for? Growers don't want their pesticide products to land on your plants any more than you do. With good neighborly communications, not only can herbicide injury be prevented but also long drawn out court cases can be avoided.

A helpful publication on this topic is, "Reducing Pesticide Drift: Specialty Crops and Conventional Crops as Good Neighbors" (Adobe PDF).

Additionally, if you have a particularly sensitive crop or area that must be protected from pesticide drift, let neighboring applicators know about it. You can register your sites at, 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.

What to do if you suspect spray drift. Once again, neighborly discussions are important. Perhaps the two of you can 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 row 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 photos of herbicide injury on landscape plants. Search by problem and then type in "herbicide". The pictures were the result of some recent U of I demonstration plots. You can even use your smart phone to view the pictures. Also, these pictures and more are available as a pocket sized, spiral bound flip book for $10. To purchase, call U of I Crop Sciences at 217-333-4424.

You can send affected plant samples to the University of Illinois Plant Clinic. 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 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.

The complaint process. 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.

Will affected plants die? That is the million dollar question and the answer is that it depends. 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 fertilizer, moisture, and light) the more likely it is to survive.

For more drift resources, check out the University of Illinois Pesticide Safety Education web site. (Michelle Wiesbrook)

Michelle Wiesbrook

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