North Dakota State University
NDSU Extension Service
Volume 16, No. 1, January 1998
IPM
NDAWN Beneficial to Integrated Pest Management
1998 Fungicide Guide–Small Grains
Pest Control
Words of Wisdom Concerning Pest Control
Are There Desirable Weeds?
Meeting the Challenges of pH Sensitive
Herbicides
New Products: Maxim registered for potato seed
piece treatment
New Products: Ridomil Gold
Sugarbeet Diseases
White Mold on Dry Beans
In This Issue
Coordinator Comments
Law
Pesticide Perceptions
Storage and Handling
Safety
Education
Pesticide Training
The development of the North Dakota Agricultural Weather Network (NDAWN) has been of great benefit in implementing integrated pest management programs in North Dakota. Weather data from 49 automated weather stations located in North Dakota and along the Red River Valley in Minnesota are readily available through computer access or telephone access. The automated weather stations provide hourly data on air temperature, relative humidity, dew point, rainfall, solar radiation, barometric pressure, bare soil temperature at 4 inches, turf soil temperature at 4 inches, wind speed, and wind direction, plus daily averages are available for total corn growing degree days, total wheat growing degree days, and total sunflower growing degree days. Additional information is available on crop water use, plus summary maps of various weather parameters.
These timely weather data have become keys to more efficient and more profitable pest management. The data have been used by NDSU researchers to develop crop, insect, and disease prediction models, which in turn have been taken to the growers and crop advisors via extension educational programming and use of telephone hotlines and industry pest alerts. Specific examples include the use of the growing degree day information for prediction of emergence of orange wheat blossom midge, and use of weather parameters in the prediction model for early blight and late blight of potato. Use of NDAWN for information about wind speed and wind direction also has helped pesticide applicators in applying pesticides at a time that would be of less risk to non-target crops.
Back in 1989, Dr. John Enz, NDSU Soil Science Department, in cooperation with the High Plains Climate Center at the University of Nebraska, established a network of six automated weather stations in North Dakota. Sixteen stations were added in 1993 through a joint project with the Department of Atmospheric Sciences at the University of North Dakota. Further cooperative efforts with the NDSU Extension Service, private and public cooperating landowners and commodity organizations allowed the network to expand to 49 locations by 1997. Many of us are dependent on this network for timely information for pest management and greatly appreciate the efforts by Dr. Enz and his cooperators in establishing and maintaining this vital weather network.
(Submitted by Marcia McMullen, Extension Plant Pathologist/IPM Coordinator)
Few changes have been made in the small grain sections of the 1998 Fungicide Guide. This guide can be found in the 1998 Crop Production Guide and also will be available at county extension offices as a separate publication. The 1998 guide does indicate a change for Dividend seed treatment products. Dividend (difenoconazole) is now sold as a combination product, combined with mefenoxam or Apron, for additonal control of Pythium damping off. The trade names are Dividend Apron XLLS Twin Pak or Dividend XL RTA.
(Source: Marcia McMullen, IPM Coordinator)
Pests will always be with us, and we will need to use pesticides to control them. That statement has nothing new in it. The problem with pesticide use today is not so much the pesticide residue or environmental problems they may cause, but the emotional reactions they provoke from a small minority of the population. You, the pesticide applicator, are in the "public's eye" — watched closely for not so much for what you do that is right, but for an opportunity to pounce when you slip up.
I have found the people involved in this business - both the applicators and the inspectors — to be rational, reasonable individuals. No one in their right mind wants to degrade the environment we live in to the point of non-support. It is in the interest of all, then, to use pesticides wisely, according to the very expensive labels that were developed with each pesticide product. While I will not claim to be a pesticide expert, it seems the manufacturers are attempting to come up with products that are more environmentally friendly, require less per unit area of treatment, and more target pest specific.
Additionally, resistance is being bred into many of the plant materials available on today's marketplace. The endophytes in cool season grasses, Acremonium spp., are providing the homeowner, parks manager, and sports turf manager with not only surface feeding insect control, but with increased resistance to disease and weed pressures as well. Researchers have also studied the effects of various nutrient regimes on the turf grass system's ability to resist weed, insect, and disease invasion. Irrigation management scrutiny has come into the scene as well, with more sophisticated equipment becoming available to monitor water needs in turfgrass. For most homeowners, about the only action needed by those who have automatic irrigation systems is to cut their watering practices in half!!
The point I am attempting to arrive at is to try get you to become environmental managers, with pesticides as just one of your tools — not the only one! When a pest makes inroads in a home lawn, park, or athletic field to try and find out what caused it to get established before reaching for the pesticide. In some instances, it may be controlled through a change in cultural practices by the homeowner, grounds keeper, or pesticide applicator. Instead of taking the approach, "Sir/ma'am your lawn has a bad invasion of weeds, so I am going to spray this herbicide to take care of it," — say instead, "Your lawn is badly infested with a broad leafed weed, which will require herbicide treatment to bring it under control, much the same way a doctor would prescribe a medication to bring a particular malady you may have, under control. Now, what can we do to keep this from happening again?"
The operative ideas in the above paragraph are management and we. You are teaming up with the homeowner to help them manage the problems, making them in part responsible for the final product, with you being the expert and the homeowner being the assistant. You can then offer them a monitoring service rather than a spraying service. It is your time that is worth the money the customer is paying for, not the material being applied! Admit it, you are applying diluted water which isn't all that costly, but your labor is! This means that you must be more articulate, observant, and sensitive to customer relations as well as being a good technician at mixing and applying the pesticides.
Does this sound like IPM? You bet it does. Going back to the basic rationality that most people possess concerning pest control, if you make it known that your goal is to have a good looking piece of property without environmental degradation, using pesticides only when all other options fail, you are building a unique business — and making yourself "crank proof" from the minority vociferous elements.
I want to return to the concept of management, which is defined as: Determining what must be done and achieving results through the efforts of oneself and other people. Management is planning, organizing, staffing, directing, and controlling the business resources toward the accomplishment of established objectives and goals. Nowhere does management imply eradication. If you make your business management objectives and goals to include providing a better environment for human use, with the minimal use of pesticides, you will attract a lot of favorable attention. Management includes not just yourself, but the people you come into contact with — your employees, of course, and your customers as well.
Management means responsibility and authority. Nothing will contribute to employee or customer turnover faster than when the appointed manager or proprietor lacks these qualities. It often means "eating crow," which is humbling, but the taste stays for a long time, and before you know it, with continued efforts in management of time and resources, you will be eating less!
Winter in our part of the country is a good time to sit and think about what needs to be identified and diagnosed as recurring problems in your turf, or pest control business over the past season, and what you can do to minimize such problems for 1998.
(Submitted by: Ronald C. Smith, NDSU Extension Horticulturist and Turfgrass Specialist)
Phytoremediation, the use of plants to clean up sites contaminated by toxic waste, is being used as opposed to conventional methods. Heavy metals, such as lead, are being removed from soil by plants. Tolerant plants absorb the metal during growth. It is then removed when plant material is harvested. The process takes more time, but savings of financial and natural resources offset the time involved.
Mustard greens and pumpkin vines are boing used to clean an old Magic Marker factory site in Trenton by Phytotech, a New jersey based company that pioneered the use plants for this purpose.
Indian Mustard (relative of broccoli): Industrial heavy metals lead, chromium, cadmium, zinc, copper, and selenium.
Goosefoot (relative of lambsquarters, Russian thistle, and sugarbeet): Salt pollution from petroleum production.
River Reeds: Runoff from airplane de-icing agents.
Poplar trees: TCE (dry cleaning solvent), petroleum, other groundwater contaminants.
Alfalfa: Fertilizer spills — special alfalfa varieties that absorb nitrogen from ground and not air.
Horseradish: Chlorinated phenols and anilines (common industrial waste from metal production, paper bleaching, other processes.
Kochia and Multiflora Rose: Herbicide spills at agri-chemical dealer lots. Kochia must be mowed before it sets seed to prevent spread to desirable areas
(Submitted by: R.K. Zollinger, NDSU Extension Weed Specialist)
It will take a combination of producer education, soil sampling and mapping activity to more accurately describe soil pH levels in individual fields and industry involvement in better publication of pH restrictions to find practical solutions to the problem of pH sensitive herbicides.
Some companies have gone to great lengths in their labels to spell out pH restrictions for subsequent crops, while others seem to rely on local sales representatives to provide carryover and crop restriction information. Other companies may have limited knowledge of product performance under pH extremes, or the information may have been omitted by marketing personnel to improve the product image. Several products have been registered without reliable data on herbicide data on herbicide breakdown and degradation. Consequently, producers and ag retailers find two years later that local conditions of high/low pH produced areas of excessive crop damage and distrust due to carryover. Having good data in hand before product registration would help make product introduction of pH sensitive herbicides less painful for end-users and retailers. Making technical publications readily available to producers explaining the affects of pH on herbicide effectiveness and persistence would be valuable to ag-supply stores and the producers and help prevent unfortunate situations.
In no-till and minimum tillage fields, the traditional method of 0-6 inch or 0-8 inch soil cores may not be adequate. Instead, a 0-2 inch core depth and a 2-6 inch core depth may be needed, since application of limestone to the surface may increase surface pH more than expected or application of nitrogen fertilizer to the surface may cause a drop in pH at the surface. Both conditions could affect herbicide performance and carryover potential.
(Submitted by: D.W. Franzen, NDSU Soil Science Specialist, and R.K. Zollinger, NDSU Ext. Weed Specialist)
Maxim was recently registered for potato seed piece treatment. It is registered for control of silver scurf, seed borne Rhizoctonia stem canker and Fusarium dry rot. Maxim is highly effective against silver scurf, providing protection not only during the cropping season but also into storage. This does not imply that Maxim has that long a residual. However, the positive effect in storage has been observed in NDSU trials. It has been suggested that perhaps Maxim reduces the inoculum level (the number of infection units) so much that there is an effect throughout the season and into storage. Maxim is also highly effective against seed borne Rhizoctonia stem canker and Fusarium dry rot.
The Maxim registration is welcome since silver scurf has become a major disease in recent years. The silver scurf pathogen has developed resistance to the benzimidazole fungicides TBZ or Mertect, used as both a seed piece treatment and for treatment of tubers going into storage, and Topsin M, used as a seed piece treatment. Although silver scurf was not on the Mertect label, use of Mertect on tubers going into storage may have provided control not only of Fusarium dry rot, but also of silver scurf. Since resistance became widespread in the silver scurf pathogen, the disease has become more difficult to control.
NDSU research (Rodriguez et al) has demonstrated that silver scurf spreads in storage. Modern storage facilities are more likely to maintain high humidity levels, favoring silver scurf spread. Further silver scurf research is in progress at NDSU.
Maxim, with an active ingredient of fludioxonil, represents a new class of chemistry. It is considered "environmentally friendly" by the Environmental Protection Agency, and was granted "Fast Track" registration by the Agency.
The various formulations of Ridomil will be phased out and replaced by similar formulations of Ridomil Gold. Some Ridomil Gold formulations will appear to have half the active ingredient of similar Ridomil formulations yet have similar label rates. This may precipitate some questions from knowledgeable applicators and producers. The active ingredient occurs in two isomers, one that is highly active and one that is relatively inactive. Ridomil contains both isomers, but Ridomil Gold contains only the highly active isomer. Thus the total Ridomil Gold active ingredient applied to a crop may be half that of the Ridomil active ingredient applied to the same crop, yet provide the same level of disease protection.
Aphanomyces Root Rot was more common than in previous years, and was more severe in mid and northern parts of the Red River Valley than in previous years. Aphanomyces is favored by warm and wet soils. Damage is greatest if warm and wet soils occur early in the season so that the plants are infected when young. Delayed planting due to wet or flooded soils may have played an important role in some of the damage that occurred. Most sugarbeets probably were planted on fields that had sugarbeets in another wet summer (1993 or 1994); the Aphanomyces pathogen likely built up in the previous season to economic levels, and these levels were expressed in 1997. Use of Tachigaren seed pelleting in conjunction with an Aphanomyces tolerant hybrid is the best approach to managing Aphanomyces, although this provided less disease management than desired in some fields in 1997.
Cercospora Leafspot was more severe in the southern Red River Valley and southern Minnesota. Tolerance to Super Tin and resistance to Benlate and Topsin M is widespread in southern Minnesota and as far north as Crookston and Grand Forks in the Red River Valley. A management plan for 1998 will be provided later but will involve much of what was used in 1997.
White mold potential was high again in 1997, although reports from selected county agents suggest that the amount of white mold at the end of the season was less than in 1996. This may be due in part to a shift in varieties. County agents indicated that less of the highly susceptible pinto variety Othello was grown in their counties and that more of the newer varieties were being grown. Many newer varieties are less susceptible than Othello, although they are far from being resistant. Data from NDSU dry bean breeder Dr. Ken Grafton's variety trial at Erie indicate that Hatton and Chase had less white mold than Othello. Fargo, Maverick, Winchester, Remington and Frontier had considerably less white mold than Othello. In 1996 Dr. Grafton's navy variety Norstar became the leading variety in North Dakota, followed by Schooner. The Erie trials indicated that both of these varieties had less white mold than Upland and Agri 1, which were the leading varieties a few years ago.
Effect of total rainfall/irrigation on white mold. Dr. Dick Meronuck, extension plant pathologist, University of Minnesota, has five years of research data from the irrigated research station at Staples, Minn. He measured the total amount of water (rainfall plus irrigation) from June 1 until 10 days after the initiation of bloom and determined the probability that a white mold spray would be economic. When the total water during this period was 3-5 inches, a white mold spray would be economic only 20% of the time. When total water was 5-7 inches, a white mold spray would be economic 65% of the time. When total water was over 7 inches, a white mold spray would be economic 85% of the time.
Irrigation management and white mold. Dr. Meronuck's research demonstrated that avoiding of excessive irrigation can help reduce the levels of white mold in irrigated dry beans. He found that plots irrigated when soil water tension (swt) reached 65 cb during the period from planting to 10 days into bloom had the lowest disease levels and the lowest yield losses. Plots irrigated when swt reached 65 cb during the period from early July to 10 days into bloom, then irrigated when the swt reached 30 cb for the rest of the season showed a slight increase in disease and yield loss. Plots irrigated at 30 cb from early July to 10 days into bloom had the highest disease levels and the highest disease losses. Use of both irrigation scheduling and a fungicide provided the most effective means of controlling white mold.
(Submitted by Art Lamey, Extension Plant Pathologist, NDSU)
[ In This Issue /
Coordinator Comments ]
[ Law ]
[ Pesticide Perceptions ]
[ Storage and Handling / Safety ]
[ Education / Pesticide Training ]
Volume 16, No. 1 -- January 1998
NDSU Extension Service, North Dakota State University of
Agriculture and Applied Science, and U.S. Department of
Agriculture cooperating. Sharon D. Anderson, Director, Fargo,
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