The perfect soil-applied herbicide would control weeds for the necessary time, then instantly degrade, and never move off-site into surface water or groundwater. It would never be present to affect the growth of subsequent crops. Herbicides have played an important part in increasing farm profits in Illinois, and few topics better portray the need for balance between environmental, crop-production, and societal interests. Atrazine contamination of rural and community water supplies is a classic example of a problem that has financial, environmental, and agronomic aspects.

Despite the recent introduction of transgenic crops that rely primarily on post-emergence herbicide applications, most crop acreage in Illinois receives a soil-applied herbicide application. Once herbicides are in the soil environment, they are subject to many types of physical and chemical dissipation processes. The fate of herbicides has far-reaching consequences, such as water quality, weed control, and herbicide carryover to rotational crops.

Current issues that are being addressed include the efficacy of early preplant herbicide applications, the efficacy of grass-control herbicides in dry soils, the behavior of herbicides under heavy rainfall, herbicide carryover to rotational crops, and the role of soil-applied herbicides in transgenic cropping systems. An emerging topic of environmental interest is the release or binding of commonly used herbicides in the aquatic environment. Recent flooding in the Midwest has raised questions about the fate of soil-attached herbicides that are either inundated in place or that travel as sediments.

Herbicide persistence is an important property of soil-applied herbicides, and some postemergence herbicides, that allows for extended weed control. When the herbicide remains unaltered in the soil during the crop season of application, it is advantageous. If a herbicide remains in the soil and is present when a rotational (and susceptible) crop is planted, the persistence causes herbicide carryover. Most herbicides do not carry over. Degradation rates in the soil under normal environmental conditions typically reduce herbicide concentrations to sub-lethal levels for rotational crops. Some herbicides have additional safety in that they are not injurious to rotational crops.

Shifts in the timing of herbicide application to earlier points have put a premium on herbicide persistence to coincide with weed emergence. In a broad sense, the resistance to degradation and the downward movement within the soil profile are both important for obtaining satisfactory weed control.

Herbicide persistence in soil
Persistence is an important characteristic of an herbicide, affecting efficacy, exposure to environmentally important transport, and carryover to subsequent crops. Persistence is the integrated result of all herbicide-loss pathways that act upon the parent compound when it is in the soil environment.

Degradation of many herbicides follows first-order kinetics, meaning that the rate of degradation is roughly proportional to the herbicide concentration. The "half-life," or time when 50 percent of the parent compound is gone, is a herbicide property frequently cited in technical information and promotional literature. Under field conditions, the half-life is quite variable and dependent upon environmental conditions.

Factors affecting persistence
The primary herbicide-loss pathways in soil are microbial breakdown and chemical breakdown, primarily driven by reactions with water. The effects of soil temperature and moisture on herbicide degradation are straightforward in that degradation mechanisms involving microorganisms operate best at optimal conditions for biological growth. In addition, nonbiological chemical reactions also typically are enhanced with increased temperature. Water is essential for microbial activity and increases aerobic processes up to the point that saturation occurs and gas transfer with the atmosphere is hampered.

Soil texture and organic-matter content have a surprisingly small effect on carryover because the differences in water and nutrient availability are often counterbalanced by the difference in herbicide adsorption. Thus a fertile soil, rich in organic matter, may promote faster degradation of a herbicide but also have less available to degrade, based on its greater adsorption sites.

Soil pH is important in affecting the stability of some herbicides and herbicide families. High soil pH associated with calcitic soils, overliming, or proximity to limestone gravel lanes may reduce herbicide degradation and increase carryover. This effect may be important for triazines and some sulfonylureas. Hydrolysis, an important breakdown mechanism, slows significantly at soil pH values near 7.0.

Soil moisture is often the key to efficacy of soil-applied herbicides in the field. Too much water and some soluble herbicides may be washed from the weed-seed germination zone. Wet springs following early preplant herbicide applications may delay planting and put the time of weed-seed germination out of reach of many herbicides. Too little water may hamper herbicide effectiveness and allow weeds to germinate and emerge without satisfactory control.

Herbicide performance in dry soils
Herbicide performance is dependent on soil­water relations as they affect weed-seed germination and herbicide concentrations in the soil solution. How well a herbicide works is determined by the net effect of (1) herbicide distribution in the target zone, (2) inherent strength or activity of the herbicide, and (3) herbicide solubility and concentration in the soil solution. In general, greater herbicide solubility increases diffusion into the soil and results in a greater soil-solution concentration. Under drier soil conditions, these properties may be advantageous.

After a soil-applied herbicide is sprayed onto a surface consisting of soil and crop residues, it is subjected to dissipation processes. The ability of a herbicide to remain as the parent molecule under photolytic and volatilization loss mechanisms is a function of the herbicide chemistry. Producers interested in controlling weeds are interested in several general properties of a herbicide. They want to know how well a herbicide works under dry soil and climatic conditions and how much rainfall is required to "activate" or increase efficacy to an acceptable level. Furthermore, they are interested in how long a herbicide can sit on the soil surface before rainfall comes and still work well once "watered in." The general research questions fall into two areas: (1) How much rainfall is needed to provide efficacy to soil-applied herbicides shortly after they are applied; and (2) what are the interactive consequences of delayed rainfall periods and amounts? Little is known about the behavior of common acetanilide herbicides and related compounds in limited-moisture conditions. Rainfall and soil water are critical to performance of surface-applied (PRE) herbicides, less so with incorporated (PPI) applications.

What conditions lead to carryover?
Application timing, soil pH, and climatic conditions in the intervening months between target crop and follow crop also may be important in determining the potential for herbicide carryover. Late application of postemergence herbicides that put next year's planting close to the labeled recrop interval has the greatest chance to cause crop injury. Late herbicide applications occur primarily due to planting delays caused by wet weather or wet soil conditions that prevent field operations. In temperate climates, late applications followed by dry weather minimize the time that processes such as microbial degradation and hydrolysis can operate efficiently before cold weather.

Precipitation and warm temperature reduce the chances for herbicide persistence because the potential loss pathways of leaching, microbial degradation, hydrolysis, and even surface runoff are all enhanced. Soil pH is important for herbicide families such as the sulfonylureas that exhibit a dramatic change in solubility and hydrolytic breakdown over typical pH levels of agricultural soils. Incidence of sulfonylurea injury to follow-crop soybean are associated with subtle pH differences close to the soil surface due to liming and limited tillage.

Techniques for estimating bio-persistence (herbicide carryover)
The primary reason for estimating the biologically active fraction of a herbicide in soil is to evaluate the potential injury to a rotational crop. The potential for follow-crop injury is greatest when a herbicide with soil activity on broadleaf weeds is used on a monocot and the follow crop is a dicot. Examples would be triazine carryover to soybean, cucurbits, and other dicots; and chlorimuron, prosulfuron, and other sulfonylurea carryover to dicots. Herbicides with grass and broadleaf activity that exhibit safety to soybean may carry over to injure corn, sorghum, or wheat the following year.

Summary
Bio-persistence, or the ability of the parent compound to exist in the soil, is an important feature of soil-applied and some postemergence herbicides and determines the suitability of early preplant applications, residual weed control, carryover potential, and the threat of off-site loss to surface water or groundwater. To optimize the application timing of soil-applied herbicides, a balance between persistence and the requirement for rainfall must be considered. To avoid herbicide carryover, close attention to herbicide chemistry, timing of application, and environmental conditions over the period preceding follow crops must be considered.

(F. William Simmons, Extension specialist, soil and water management)

The University of Illinois Cooperative Extension Service formally established the Pesticide Applicator Training (PAT) office in November 1996. Several functions were consolidated into one office, and accountability given to one person. Teamwork between Illinois Extension and the Illinois Department of Agriculture continues to grow, thus providing efficient services and enhancing our information resources. There have been procedural changes and added functions that may be of interest to PAT customers.

Illinois Pesticide Act 1997 Fee changes
The major changes in the Illinois Pesticide Act in 1997 were related to fees associated with the registration of pesticide products and the licensing of pesticide users. Changes have been made to the fee structure to increase funding stability for the Illinois Department of Agriculture as it relates to the state's pesticide program. The new fee structure increases generated revenues at a very gradual rate through the year 2007 (see table 1).

PAT office update
Telephone upgrade: To better serve those calling the PAT Extension office, a new telephone system was purchased that includes 24-hour voicemail, an automated attendant to walk you through available options, and a direct-rollover option to the Illinois Department of Agriculture. There are currently 56 voicemail lines, so encountering busy signals should be eliminated. With the high volume of calls per day, this system helps direct patrons to the phone service they need in a timely manner (see Quick Reference Guide).

One-stop shopping: Beginning this year, anyone desiring to buy study materials for enhancing their PAT knowledge base may do so by contacting the PAT officeby phone, fax or mail (see the Quick Reference Guide). Prior to this, two contacts were needed to register and buy publications. By combining the two options, efficiency is realized. Please note: Using your VISA or MC (including expiration date) expedites the mailing of your publications. Any order received that includes payment is processed within 72 hours.

Database enhancements to deliver professional service: A detailed analysis of our data entry needs was conducted during the past summer. As a result, our program is tailored to match exactly the needs of our PAT clients. Included in the enhancements was the addition of two relational databases that work behind the scenes to automate the customer's registration and/or publication order. The capability is now available to enter data as we talk to clientele, have the program calculate exactly what the total cost is, and provide patrons with a confirmation number before they hang up the phone. The intent is to add professionalism and confidence to the interaction between the PAT office and our customers.

PAT Quick Reference Guide Pre-registration for a commercial clinic and/or ordering of study materials may be done by fax, phone, or mail. Phone: (800)644-2123 or (217)244-2123; choose one of the following options: #1 = Register AND order study materials #2 = Register for future clinic only #3 = Order study materials only #4 = Rollover to Springfield (IDA) 800-641-3934 #5 = To speak to someone Fax: (217)244-3469 Mail: Department of NRES PAT Program 1201 S. Dorner Dr. Urbana, IL 61801 Illinois Pesticide Safety Education Website: http://www.aces.uiuc.edu/~pse/

Table 1

Pesticide-related fees from 1986 to 2007+; contained within the Illinois Pesticide Act (415 ILCS 60/1 et seq.).
Period Effective1
Fee Type	Before 86	86­87	88­90	91­93	94­97	Step 1 98­00	Step 2 01­03	Step 3 04­06	Step 4 2007+
Product registration:
per company	$0	0	250	250	250	250	250	300	300
per product	$15	15	50	100	50	100	100	130	130
Licensing fees:
Private applicators	$0	0	10	10	10	10	15	15	20
Commercial applicators	$25	30	30	50	30	35	45	45	60
Commercial operators	$10	20	20	20	20	25	30	35	40
Pesticide dealers	$0	0	100	200	100	100	100	100	100
1The effective period is shown by step and the calendar year when the fee applies.

- Rhonda Ferree

http://www.aces.uiuc.edu/~pse

The University of Illinois Pesticide Safety Education Program has joined millions of others with Internet sites. There you will find facts on pesticide safety. Annual reports and summaries areprovided for many programs, including Pesticide Container Recycling, Educational Materials, Commercial and Private PAT Programs, Worker Protection Standard, Homeowner Programs, Operation Safe Fly-in Workshops, Drift Education Activities, and Agricultural Product Misuse in Urban Settings.

The site also provides:
PAT training schedules for both the Commercial and Private clinics; pesticide-related fact sheets; training resources of ICES Pesticide Safety Educators; and additional University of Illinois pesticide-related web sites.

Patty Bingaman,Cooperative Extension Service; and Warren Goetsch, Illinois Department of Agriculture

On December 5, the US-EPA issued a civil administrative complaint charging Microban Products Co., Huntersville, N.C., with making unsubstantiated public health claims for its pesticide Microban Plastic Additive. The complaint charges Microban with making claims that certain consumer products treated with the pesticide protect children from infectious diseases caused by bacteria such as
E. coli, staph, and strep, when in fact the treatment was approved only to protect the plastic in the products from deterioration. The agency is seeking $160,500 in civil penalties.

According to the US-EPA press release, this action against Microban is meant to assure that registrants limit their claims to those permitted by the product's registration. The US-EPA feels the use of unapproved public-health claims in conjunction with the sale of consumer goods such as sponges, toys, and cutting boards may pose a risk to the public. In the case of toys, parents and child-care providers could easily conclude from the claims authorized by Microban that the mere presence of Microban in toys provides protection from harmful germs and, hence, a public-health benefit. If parents and child-care providers believe that toys are sanitary or self-sanitizing, they may not practice standard hygiene to prevent transmission of harmful germs or be as careful as they should be. The net result may be that children's health is not protected as well.

Microban Plastic Additive is registered by the US-EPA to inhibit bacterial growth in plastic. No public health­related claims have ever been accepted for this pesticide. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), it is illegal to make claims for any pesticide that differ from those claims approved in connection with the pesticide's registration.

(Rhonda Ferree, adapted from US-EPA Press Advisory on Microban)

The Office of Prevention, Pesticides and Toxic Substances (OPPTS) is undergoing another reorganization. Lynn Goldman, assistant administrator, announced on December 9 her intent to realign OPPTS to include four offices, in addition to the current OPPTS Immediate Office. Dr. Goldman said the changes are needed "to ensure that we are structured in a way that provides the most effective delivery of our programs to the public."

Two of the four offices are new: the Office of Science Coordination and Policy and the Office of Consumer Safety and Right-to-Know. Dr. Goldman felt a need to strengthen "leadership of consumer protection and rightto-know efforts." That office will have responsibility for Food Quality Protection Act (FQPA) food-safety pamphlets, antimicrobial products, consumer labeling, worker protection (including PAT programs), and other consumer-based EPA programming. The Office of Science Coordination will address policy regarding OPPTS science issues.

The other two offices existed in OPPTS previously. The Office of Pollution Prevention and Toxics has responsibility in pollution prevention, new chemicals, design for the environment, and other related programs, including those dealing with lead, PCBs, and asbestos. The Office of Pesticide Programs will deal with FQPA implementation, the FIFRA docket, all other product-registration and special reviews, minoruse programs, biopesticides, ecological risk issues, and more.

(Rhonda Ferree, taken from 12-9-97 letter from Lynn Goldman to all OPPTS staff)

Consumer labeling initiative
In 1996, the Environmental Protection Agency (EPA) began a Consumer Labeling Initiative (CLI) with the goal of making pesticide labels more informative and easier to understand. The first fruit of this project is EPA's Consumer Labeling Initiative: Phase I Report. This CLI report provides information about consumer comprehension of and attitudes toward pesticide labels and includes comments and suggestions from both consumers and professionals on how to improve pesticide labels. Last fall, the EPA issued three "Pesticide Regulation (PR) Notices" to pesticide registrants; the notices are voluntary and based on recommendations made in the Phase I Report. Following are summaries of these PR notices.

Consumer-access numbers
Although the EPA requires that every pesticide label include the name and address of the registrant, it does not require the registrant to include his or her telephone number. However, a number of registrants, particularly larger companies, have voluntarily included their telephone numbers or even a toll-free hotline as a customer service. It is easy to see the benefits to the consumer when such direct access is provided. One can also appreciate the substantial expense of providing a highquality, direct-access service. The EPA encourages registrants to include the following information on their labels: (1) their company's telephone number and/or their toll-free hotline number, with a statement indicating the kinds of information for which the number(s) should be used; (2) the National Pesticide Telecommunications Network (NPTN) hotline number, 1-800-858-7378; and (3) their Internet home page address.

Use of common names for active ingredients.
Which of these descriptors do you recognize: (1) CAS # 63-25-2; (2) chemical name: 1-Napthyl-N-methylcarbamate; (3) common name: carbaryl; or (4) trade name: Sevin? Your answer largely depends on your type of employment: Are you a toxicologist, pesticide applicator, physician, chemist, or field inspector? Descriptors 1 to 4 all indicate the same active ingredient. To make things more confusing, some active ingredients have more than one chemical and common name (for example, mothballs and naphthalene are common names for the same chemical). Striking a balance between the information that is desired by users and the information that is critical to other persons (as just described), the EPA published a list of accepted active-ingredient descriptors (common and chemical names and CAS numbers) that must be used by registrants. The EPA urges registrants to use accepted common names instead of chemical names where possible. However, if the chemical name is omitted, registrants should also list the CAS (Chemical Abstract Service) number.

Use of the term "inert" in the label ingredients statement
How do you describe the phrase "inert ingredient?" We often describe it as the "filler" and leave it at that. If you look up the word "inert" in a dictionary, you'll find that its synonym is "inactive", which means, in biological terms, "having no significant effect on or interaction with living organisms." Although most inert ingredients are NOT known to pose health effects or environmental concerns, EPA has long known and acknowledged that some inert ingredients pose greater human health risk than the active ingredient! Thus, the term "inert" may not always be accurate. The topic of "active inerts" will be discussed further in the next issue of IPR. The EPA is encouraging registrants to replace the phrase "inert ingredients" with "other ingredients."

We will keep you posted as the Consumer Labeling Initiative progresses and related "Pesticide Notices" are released.

(Bruce E. Paulsrud, Extension Specialist, Pesticide Applicator Training)

Citations:
USEPA Pesticide Regulation notices 97-4, 5, and 6
Pesticide & Toxic Chemical News. July 2, 1997. Vol. 25(36).

One of the newer regulations that producers must learn about is the Worker Protection Standard (WPS), which affects those who use pesticides in the production of agricultural plants on a farm or in a forest, nursery, or greenhouse. The WPS requires that employers teach agricultural workers and pesticide handlers how to reduce exposure to pesticides and how to lessen the harmful effects of exposures that might occur. Although there are some exceptions for family farms, if you hire even one part-time worker, you must comply with the WPS requirements.

To meet the training requirements under the WPS, employers have two options: (1) to do the training themselves, or (2) to have someone else do the training for them. Anyone holding a pesticide license is already trained according to the WPS. Employers who have attended an approved train-the-trainer program or who hold a Pesticide Applicator license may train their own workers. Pesticide applicator training clinics taught by the Cooperative Extension Service meet the WPS training requirements. In addition, workers or handlers attending such clinics for WPS reasons only do not have to take the certification examination and will receive, upon request, a training card instead of a pesticide license.

There is a significant number of migrant and permanent, Spanish-speaking workers in Northeastern Illinois. Spanish WPS handler training is predominantly done by the individual employer. The employers in Northeastern Illinois have recently requested additional help in conducting such training. In addition, employers would like the Spanish training to be more in-depth than simply WPS training.

The Illinois Cooperative Extension Service is addressing this request by offering a workshop that will qualify Spanish-speaking instructors to train handlers and workers according to the US-EPA's Worker Protection Standard requirements. This workshop will include hands-on sessions on how to conduct effective training programs and what training is required for both handlers and workers. Because this workshop will be conducted primarily in Spanish, bilingual growers, farm supervisors, labor contractors, and others interested in becoming qualified trainers should attend. Participants will receive an instructor's handbook, EPA materials, and other useful resources.

This workshop will be held February 23 and 24 at the Countryside Extension Center in Countryside, Illinois. Training will begin at 9 a.m. and continue until about 5 p.m. each day. To become an approved WPS trainer, you must attend both days. Additionally, on February 25^th, an actual handler training session will occur at Kankakee Nursery and offer an opportunity for workshop attendees to practice their newly learned skills. Although the workshop and practice session are free, seating is limited. To register or request additional information, please contact Rhonda Ferree at (217)244-4397 (English speaker) or Susan Bauer at (312)795-0000, ext. 223 (Spanish speaker).

The development and/or publication of this newsletter has been supported with funding form the Illinois Department of Agriculture.

Rhonda J. Ferree, Extension Horticulturist, Pesticide Applicator Training

Bicep/Bicep Lite (metalachlor/atrazine), Novartis

Registrations were voluntarily canceled, effective 3-30-98.

Regent (fipronil), Rhone Poulenc

Received approval for use on corn to control rootworm and European corn borer.

Roundup Ultra (glyphosate), Monsanto

Added use on sugar beets and canola grown for seed.

Touchdown 5 (sulfosate), Zeneca

New burndown-herbicide formulation containing 5 pound/gallon active ingredient and requiring no tank-mix adjuvants.

"Unless otherwise noted, adapted from Agricultural Chemical News, November 1997, December 1997"

- Bruce Paulsrud

Intrepid (methosyfenozide), Rohm & Haas

A new insect-growth regulator for use on vegetables and ornamentals.

Neu 1165M Slug & Snail Bait (iron phosphate), W. Neudorff

A new active ingredient for noncommercial food crops, ornamentals, greenhouses, and lawns.

Pentac (dienochlor), Novartis

Due to the high cost of reregistration, Novartis has proposed to cancel registration for all uses of this product, including use on fruit trees and ornamental plants.

"Unless otherwise noted, adapted from Agricultural Chemical News, November 1997, December 1997"

- Bruce Paulsrud

Clearigate (copper complexes), Applied Biochemists

New aquatic herbicide claiming to eliminate algae in 24 hours and to knock down rooted plants within several days.

Novartis

The company is selling its worldwide spray-on Bacillus thuringiensis (B.t.) business to Thermo Trilogy Corp. for about $19 million. Labels include Able, Agree, Design, CoStar, Favelin, Delfin, Teknar, Thuricide, and Vault.

Plateau (imazapic), American Cyanamid

Received registration for weed control and turf-growth suppression on roadsides and other noncrop areas.

Verbenone Pouch (pheromone), Phero Tech Inc.

New forestry pest-control product.

"Unless otherwise noted, adapted from Agricultural Chemical News, November 1997, December 1997"

- Bruce Paulsrud

Eagle (fenbuconazole), Rohm & Haas

Added over 90 ornamental species to the label. Turf label changes include increased rates and application intervals.

J.R. Simplot

Jacklin Seed Company of Idaho, a major supplier of turfgrass seed, was acquired by J.R. Simplot and will be called Simplot-Jacklin.

Kansel + (pendimethalin/oxadiazon), Scotts

New combination product for preemergence weed control in turf, formulated on methylene urea controlled-release fertilizers.

Pre Pair (napropamide/oxadiazon), UHS

A new granular formulation for use on nursery stock.

"Unless otherwise noted, adapted from Agricultural Chemical News, November 1997, December 1997"

- Bruce Paulsrud

Ammo (cypermethrin), FMC

Added the use on brassica crops.

Apogee (prohexadione-calcium), BASF

New plant-growth regulator for use on apples to reduce vegetative growth, allowing more light to penetrate the canopy, resulting in improved coloring. Also claims to reduce the severity of fire-blight infection.

Champ Formula 2 (copper hydroxide), Agtrol

Added the use on parsley and the control of bacterial fruit blotch on watermelon.

(Rhonda Ferree, adapted from Agricultural Chemical News, November 1997, December 1997)

Final (brodifacorum), Bell Labs

New pellet and blox formulation for mouse and rat control.

"Unless otherwise noted, adapted from Agricultural Chemical News, November 1997, December 1997"

- Bruce Paulsrud