Illinois Pesticide Review
November / December
In This Issue
Good Things to Know for a Simplified Registration and Licensure Process
Letters received from IDA (Illinois Dept. of Ag.)
If you haven't received your retest (white paper) or renewal (pink or yellow) letter from IDA, you should soon. If you need to test this year, it will say so in sentence two. Ignore the return envelope that was sent if you got one. The "Instructions for Attending a Clinic" is really just a check list of information you will need to know to get your license. Do not return it.
Your Social Security Number will be needed when you take the test. Testing is required every 3 years. However, Commercial (not Private) licenses must be renewed yearly (expire 12/31). For renewals, fill out the enclosed application form and mail the specified payment to IDA.
IDA does not take debit or credit cards. Some companies have expressed concern because they do not have a checking account. Alternate payment options include using a money order or personal check and being reimbursed. Universities may use account transfers. Please plan accordingly and allow for extra time that may be needed for paperwork.
For testing only (without training), it is recommended that you either attend a Test Only clinic or schedule an appointment with IDA at DeKalb or Springfield. Walk-ins for testing at training clinics will be seated as space allows. Attendance at training will guarantee a saved seat for testing.
Test early to have your license when you need it!
The IDA encourages applicators & operators to take the test early in the year and not wait until the last minute as there are hundreds of people taking exams each month.
Passing the exam does NOT make you licensed. You cannot apply pesticides until the IDA receives a check and a completed application. Afterwards, the IDA will mail your license to your employer's address. Only then you are licensed to apply pesticides.
Have a New Employer?
The IL Pesticide Act says you must inform IDA.
Important Testing Information
• For Training Clinics:
o Commercial (toll free) 800-644-2123 or 217-244-2123
o Private (toll free) 877-626-1650
o Website (Commercial and Private) www.pesticidesafety.illinois.edu
• For Test Only Clinics:
o Commercial – (toll free) 800-644-2123 or 217-244-2123, www.pesticidesafety.illinois.edu
o Private – Contact the individual site. For the name and number, refer to www.pesticidesafety.illinois.edu.
• For Private Clinics: Training 8:00am-11:30am; Testing 12:30pm-2:30pm
• For Commercial Clinics: General Standards training 8:00am-11:30am; for Categories and Testing refer to www.pesticidesafety.illinois.edu or the orange schedule booklet.
• Testing only (Private and Commercial both) is free
• Training Clinics:
o Private $30 (Online training is $15)
o Commercial $40
o Private $30.00
• Dealer $100
• Applicator $60
• Operator $40
• Public1 Applicator $20
• Public1 Operator $15
• Commercial not-for-hire2 Applicator $20
• Commercial not-for-hire2 Operator $15
1) Public Examples: County forest preserves, municipalities, public golf courses, etc.
2) Commercial Not-For-Hire Examples: Building services for corporate complexes, schools, grounds maintenance, private golf courses, large greenhouses, etc. (apply on property of their employer only).
What's the Potential for Herbicide Carryover in 2012?
Producers contended with precipitation "extremes" in the 2011 growing season that could lead to herbicide carryover, said Aaron Hager, University of Illinois Extension weed specialist.
"Wet soil conditions slowed spring planting and delayed applications of soil-residual herbicides in many areas, whereas particularly dry conditions were encountered across large geographic areas as the season progressed into July and August," he said.
Dry soil conditions undoubtedly contributed to less-than-ideal performance of some foliar-applied herbicides, he said. Weeds growing under hot and dry conditions were frequently "hardened off" and difficult to control with post-emergence herbicides.
"Poor weed control is one obvious outcome of a dry growing season, but herbicide degradation and dissipation also can be reduced when soil moisture is limited," Hager added.
Reduced herbicide dissipation in soils may result in herbicide residues high enough to cause injury to rotational crops. Hager said several factors should be considered when determining the potential for herbicide carryover, including the herbicide applied, when the application was made, soil pH, and soil moisture.
The labels of most soil-residual and many foliar-applied herbicides indicate the required amount of time between application and planting a rotational crop. Late-season applications of herbicides that possess soil-residual activity can result in rotational crop injury if the rotational interval is not achieved, he said.
In addition, soil pH affects the stability and persistence of some herbicides. Soil pH of 7.0 or greater may slow the dissipation of certain herbicides by reducing the degradation process known as hydrolysis.
"Even under conditions of adequate soil moisture, degradation of some triazine and sulfonylurea herbicides under high pH soil conditions can be reduced enough to result in carryover," he said. "Soil moisture is often the most critical factor governing the efficacy and persistence of many other soil-residual herbicides."
Many herbicides are degraded in soil by the activity of soil microorganisms. When soil moisture is limited, these microorganism populations can be greatly reduced. Additionally, dry soils can enhance herbicide adsorption to soil colloids, reducing the availability of the herbicide for plant uptake and degradation by soil microbial populations, he said.
If herbicide carryover is a concern, a soil chemical analysis or bioassay can be performed to determine if herbicide residues are sufficiently high to cause injury to rotational crops.
"Soil chemical analyses are performed by commercial laboratories and can be a bit expensive," he said. "Bioassays, often conducted using the rotational crop of choice, will not quantify the amount of herbicide residue remaining in the soil, but can give an indication if the rotational crop might be injured by remaining herbicide residues."
(Submitted by David Robson from a University of Illinois ACES News press release.)
EPA's Pesticide Program has released a new online searchable database, called InertFinder. This database allows anyone to easily identify chemicals approved for use as inert ingredients in pesticide products, whether they're a formulator or applicator.
Users can search for inert ingredients by chemical name or Chemical Abstract Service (CAS) Registry Number to determine whether inert ingredients are approved for products that have food or nonfood uses. Search results will also provide any applicable use limitations and will flag inert ingredients for which companies have asserted data compensation rights.
InertFinder was developed in response to a longstanding need expressed by the regulated community and others for a resource that combines various lists of approved inert ingredients into a readily searchable format. For food use inert ingredients, InertFinder includes links to the Code of Federal Regulations, which is the legal record regarding inert ingredients that have exemptions from the requirement of a tolerance for residues on food.
NOTE: The system does not include information about ingredients in individual pesticide products.
The home page for InertFinder includes a link to another online searchable database called the Chemical Data Access Tool, which allows users to find health and safety information submitted to EPA under the Toxic Substances Control Act (TSCA) at http://java.epa.gov/oppt_chemical_search/ .
Pyrethrins/Pyrethroid Cumulative Risk Assessment
EPA's recently completed cumulative risk assessment indicates that exposures from the many current uses of pyrethrins and pyrethoid insecticides do not pose risk concerns for children or adults. Further, the cumulative assessment supports consideration of registering additional new uses of these pesticides. EPA issued its final pyrethins/pyrethroid cumulative risk assessment and requested comment, including information that may be used to further refine the assessment.
Once the agency completes and approves pyrethroid single chemical assessments, it is likely that new uses of these pesticides will be added, providing tools that may alleviate challenging new pest management situations such as the invasive stink bug and bed bugs.
However, cross resistance to pyrethroids is widespread in certain pests, particularly bed bugs. Pyrethroids disrupt neuron transmission, similar to the mode of action seen in organochlorine insecticides such as DDT and chlordane. Bed bugs were showing widespread resistance to organochlorines when EPA caused most organochlorine indoor pest uses to be taken off of the market in the 1970s. Organophosphates were effective against bed bugs from the 1960s into the late 1990s when EPA caused most residential uses of this chemical class to be taken off the market as a result of the Food Quality Protection Act of 1996.
The almost total reliance on pyrethroids for indoor crack and crevice pest control sprays resulted in very quick, high-level resistance development in bed bugs in buildings to one pyrethroid after another. Recent laboratory research indicates that bed bugs without pyrethroid resistance but assumed organochlorine resistance develop resistance to various pyrethroid insecticides within 18 months of heavy exposure.
The brown marmorated stink bug already exhibits apparent resistance to pyrethroids in the U.S. as treatments by various pyrethroids provide less control than on related pests. This insect was first detected in 1998 in the northeastern U.S. and is still most common in that part of the U.S. It is a serious pest of soybeans, soft fruits including peaches, and several vegetables including tomatoes.
The adults are also heavy invaders of buildings in the fall. It is native to China, Taiwan, Japan, and Korea, where it is undoubtedly treated with pyrethroids and may be developing resistance. Small numbers of this stink bug have been found in numerous states outside of the Northeast, including several Illinois locations.
The use of pyrethrins and the pyrethroids has increased during the past decade with the declining use of organophosphate pesticides, which are more acutely toxic to people and wildlife than the pyrethroids. In 2009, EPA identified the pyrethroid chemicals as having a common mechanism of toxicity and has now completed a human health cumulative risk assessment for all uses of the pyrethrins and pyrethroids.
EPA's screening level cumulative assessment considers all registered uses of pyrethrins and pyrethroids and includes exposure from food, drinking water and residential settings through oral, dermal and inhalation routes of exposure. The agency considers this cumulative risk assessment to be highly conservative because it assumes that people are going to be exposed to the highest levels of residues in food, water, and in their homes all on the same day.
For example, in estimating residential exposure the assessment assumed no dissipation of the chemicals, all individuals were exposed on the day of application, and exposure for each scenario occurred as a result of the pyrethroid with the highest risk estimate registered for that scenario.
The assessment also assumed co-occurrence of certain residential scenarios as worst-case situations. Even using these very conservative assumptions that likely overestimate exposure to pyrethrins and pyrethroids, estimated risks to both adults and children are well below the agency's level of concern.
Interested parties are invited to submit comments and input on the Pyrethrins/Pyrethroid Cumulative Risk Assessment by Jan. 9, 2012, to docket EPA-HQ-OPP-2011-0746 at Regulations.gov. The assessment and supporting documents are available in this docket. See also the agency's Assessing Pesticide Cumulative Risk website.
For additional information: Assessing Pesticide Cumulative Risk/ Common Mechanism Groups; Cumulative Exposure and Risk Assessment visit http://epa.gov/pesticides/cumulative/common_mech_groups.htm
(Slightly modified EPA release of November 10, 2011, with the third through sixth paragraphs written by Phil Nixon).
Boom Height, Nozzle Spray Angle, and Drift
For the foreseeable future, my IPR articles will feature a review and an explanation of scientific journal articles related to pesticide application equipment and drift reduction. My goal is to take research project results, both current and past, and get them out of a dusty library and into the real world where they might do some good.
In this article I will focus on a paper that examined the relationship between boom height, nozzle spray angle, and drift potential (Miller et al., 2011). First, some background on why this is important. One of the common ways applicators are encouraged to lower their risk of drift is by lowering the boom.
The closer the boom is to the target, the less exposure the spray has to the wind. Raising the boom up means a longer distance the spray has to travel, which increases the time the droplets are exposed to the wind, which in turn increases the risk of drift.
Related to this is the nozzle spray angle and pattern overlap. In order to make a uniform application, flat-fan nozzle patterns need to be overlapped correctly. The amount of overlap required is determined by the nozzle fan angle (angle between the two outer edges of the spray pattern), nozzle spacing, and boom height. To increase overlap, you can decrease the nozzle spacing or increase the boom height. To reduce overlap, you can increase the nozzle spacing or decrease boom height.
Using a nozzle with a wider spray angle means nozzles can be mounted farther apart or operated with the boom lower without reducing their overlap. This is the advantage of using a wider spray angle: the boom can be lowered, thus reducing the risk of drift.
As an example, let's examine the optimum spray heights for extended-range nozzles as published by the manufacturer. With 20-inch nozzle spacing, the recommended height for an extended-range nozzle with an 80-degree fan angle is 30 inches. With the same 20-inch spacing, an extended-range nozzle with a 110-degree fan angle should be operated at an ideal height of 20 inches.
There is, however, a small negative and it is related to spray droplet size. For most nozzle types and sizes, a nozzle with a wider spray angle will create a slightly smaller droplet spectrum than a nozzle with a narrower spray angle.
If we compare the droplet size of two 04 tips (flow rate of 0.4 gallons per minute at 40 psi) operated at a pressure of 20 psi, we find that an extended-range nozzle with an 80-degree fan angle creates a coarse droplet spectrum, whereas the nozzle with a 110-degree nozzle angle creates a medium droplet spectrum.
As you are no doubt aware, spray droplet size plays the critical role in drift mitigation – smaller droplets are more prone to drift. So the benefit of using the wider nozzle angle to lower the boom is slightly offset because of the smaller droplet size.
The current trends in the application industry are towards wider-angle nozzles. In fact, many of the new drift reducing nozzle designs available from a variety of manufacturers are only available in 110 or wider spray angles. Two other important industry trends are longer booms and higher operating speeds.
What those two trends translate to is booms that are operated at greater heights in order to avoid damage to both the boom and the crop during an application. So in essence, applicators are not able to take full advantage of the wider spray angle because they need to keep the spray boom higher in order to avoid damage.
The objective of Miller et al. (2011) was to examine the relationship between nozzle fan angle, droplet size, and boom height. The researchers used a combination of wind tunnel and field experiments to see if using a narrower spray angle reduced drift compared to a wider spray angle when the boom was operated at a height above the recommended optimum.
Their theory was that since the boom was high, a nozzle with a narrower angle would still provide sufficient overlap for a uniform application, while also creating a larger droplet size, which would lower the risk of drift. They compared standard 03 flat-fan nozzles with 110, 80, and 65-degree fan angles. The droplet size of these nozzles was measured using an optical imaging pulsed laser system. For the wind tunnel they used boom heights of 14, 20, 28, and 34 inches. The field trial used boom heights of 20, 28, 35, and 43 inches.
The results of the droplet size measurements were as expected. At a pressure of 44 psi, the 110-degree nozzle produced 5.7 percent of its total spray volume in droplets smaller than 100 microns in diameter. For reference, 100 microns is about the diameter of human hair; spray droplets 100 microns in diameter and smaller are those considered most at risk of drifting off-target.
The 80-degree nozzle produced 4.9 percent and the 65-degree nozzle produced 3.0 percent of their spray volumes in droplets smaller than 100 microns in diameter. This confirmed that as nozzle angle increases, the amount of small droplets created and therefore the risk of drift increases.
The wind tunnel results showed, as expected, that increasing boom height increased the amount of drift. At every height, as spray angle narrowed, the amount of drift decreased. The 65-degree nozzle at a height of 28 inches produced less drift than the 110-degree nozzle at a height of 20 inches. However, the 80-degree nozzle at both 28 inches and 34 inches had more drift than the 110-degree nozzle at 20 inches.
This shows that keeping the boom as low as possible is an effective means of drift reduction, and that using a narrower angle nozzle will not completely compensate for a higher boom in terms of drift reduction. Field trial results showed the same trends as the wind tunnel experiment.
The authors concluded that when operating a boom at heights greater than 20 inches, the use of narrower spray angles will reduce the risk of drift. When using narrower spray angles, though, it is critical to make sure you still have sufficient overlap to provide a uniform application in order to achieve an effective application. The goal of any pesticide application should be to find a suitable balance between efficacy and drift minimization.
Source: Miller, P.C.H., M.C. Butler Ellis, A.G. Lane, C.M. O'Sullivan, and C.R. Tuck. (2011). Methods for minimizing drift and off-target exposure from boom sprayer applications. Aspects of Applied Biology 106 (2011): 281-288.
(Submitted by Scott Bretthauer)
Two Native Trees with Potential Disease Problems
Two diseases have the potential for wreaking havoc on two native trees – the bur oak (Quercus macrocarpa) and black walnut (Juglans nigrans).
The thousand cankers disease hasn't been confirmed in Illinois yet, but it has been found on black walnuts in Tennessee, Pennsylvania and Virginia in the past year. The disease has been reported for close to a decade in the Southwest US.
Thousand cankers disease, which cannot be currently treated, produces small and easy-to-miss cankers when few, but the cankers can become so numerous that they prevent nutrients and water moving throughout the walnut resulting in death.
Like Dutch elm disease (DED), small beetles, specifically the walnut twig beetle, carry a fungus (Geosmithia morbida) that is transmitted to the tree when the adult beetles tunnel under the bark.
In response to the disease, Purdue University have helped develop a website (www.thousandcankers.com) aimed at providing information about this potential disease to homeowners, landowners and foresters.
Bur oak blight (with the acronym of BOB) has been making its presence known in Iowa the last couple of years, though researchers suspect it has been around for awhile.
Bur oak blight is caused by a leafspot fungus (Tubakia spp.), most noticeably infecting trees after wet springs. Symptoms start on the lower limbs with leaves dying along veins and producing wedge-shaped areas at tips or sides of the leaves, usually with browning showing up in July and August. The symptoms appear to intensify year to year in trees, eventually affecting the entire crown of the tree. Without the leaves, the tree is weakened, stressed, and can die from the disease or invasion from other pathogens or insects such as the two-lined chestnut borer.
Dead leaves hang on throughout the winter, which is an identifying factor for the disease. The leaves allow fungus to overwinter on the old leaf petioles, produce spores in the spring and infect the newly emerging leaves, similar to anthracnose on sycamore and maples.
What's interesting is that there appears to be some resistance. It's possible one tree could be totally infected, while a bur oak right next to it shows no symptoms. In Iowa, upland bur oaks seem more affected than forested colonies or bottomland stands.
Injections of propiconazole (Alamo) into bur oak in late May or early June, before symptoms appear, have been effective. However, propiconazole can be phytotoxic to bur oak at high rates, and the treatment is costly.
As much as we hate to say it: stay tuned. In the meantime, scout your walnuts and bur oaks weekly throughout the summer and keep them healthy.(Submitted by David Robson and Travis Cleveland.)