Field Crop News

Website Address: http://fcn.agronomy.psu.edu/

April 4, 2006    Vol. 06:01

IN THIS ISSUE:

Production

Pest Management

EDITORIAL

Welcome to the first edition of Field Crop News in 2006! The Penn State Crop Management Extension Group (CMEG) is committed to offer you timely information about the full range of crop management issues, including variety selection, tillage, planting, equipment choices, liming and fertilization, weed, pest and disease management, soil management, manure handling, harvesting and storage and more. This first issue does not have reports from the regions or a weather report. Those will appear in future issues of FCN. For a successful 2006!

Greetings,
Sjoerd Duiker
FCN Editor, 2006
Soil Management Specialist

PRODUCTION

OPTIONS FOR NO-TILL ALFALFA

In true no-till systems farmers strive to use continuous no-till, diverse crop rotations, and living roots growing in the soil year-round. Forages are often the weak link for continuous no-till: only 10% of forages are established no-till. By respecting a few ground-rules, however, no-till establishment of alfalfa can be as, or more, successful than establishing alfalfa with tillage.

Benefits of no-till establishment of alfalfa include:

Potential disadvantages of no-till establishment of alfalfa:

Spring establishment of alfalfa is very common in Pennsylvania. Alfalfa needs to be established between March 1st and April 1st in the southern part of Pennsylvania and between March 15th and April 15th in central Pennsylvania. No-till alfalfa can be successfully planted in a field that was in corn silage or soybeans last year. If the alfalfa is established after corn silage it is recommended to plant into a fall-planted oat cover crop. The oat cover crop will winterkill around the turn of the year, and there is therefore no need to worry about killing this cover crop in the spring. This can be a challenge with cover crops that survive the winter such as rye or wheat because of limited glyphosate activity with cool temperatures early in the spring when alfalfa needs to be established. The oat cover crop should not produce too much residue (it should winterkill when it is less than one foot tall). Sclerotinia is not a big problem in the spring, so the oat mulch is not likely to present a disease problem at this time. Soybean residue needs to be very evenly distributed to allow successful no-till alfalfa establishment in the spring. No-till alfalfa establishment after corn grain harvest is not recommended because of the heavy residue cover that is present. It becomes almost impossible to plant the small alfalfa seeds at the appropriate depth if corn residue is present.

It is not recommended to establish alfalfa into an old permanent grassland. These fields tend to be of lower productivity: they may be shallow or poorly drained, and pH and fertility are typically low. Weeds can be a problem in these old sods. A flush of weeds usually comes up after the sod has been burnt down with a herbicide, which can severely compete with the new alfalfa stand. If the soil is suited to alfalfa, a good option is to burn the old permanent grassland down in the fall, soil test and apply manure, fertilizer and lime in the fall, no-till corn in the spring which is harvested for silage early in the fall and followed by winter wheat or barley. The alfalfa can then be no-tilled in the fall into the small grain stubble. If the soil is not well suited to alfalfa it is better to renovate the grassland with red clover. Red clover is better suited to poor soil conditions than alfalfa.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

IS YOUR PLANTER READY?

The quality of your corn stand will largely depend on planter performance. An irregular stand can easily cost you 10% of your yield. Planter performance is especially critical in no-till because of high penetration resistance, crop residue at the soil surface, and a rough soil surface. Inadequate planting will result in uneven seed depth and plant spacing. Hairpinning is common if coulters and row cleaners don’t work properly. Here are some tips to prepare your planter for the new season.

Meters. Metering units have to work well or you’ll get frequent skips, doubles and triples. To guarantee optimal performance, take metering units apart every winter. Remove dirt and clean the hood with soapy water (no kerosene, diesel or oil should ever be used in metering units!). Replace cracked plastic covers. Replace broken fingers in a finger-pickup meter. Check tension on the fingers with a feeler gauge and adjust if needed. Seed brushes need to be replaced when worn. If a groove has formed in the chromium house of the metering unit it is time to replace it. The belt (in finger pick-up meters) should be flexible, not have cracks in it, and should be clean. Clean with soapy water and let it dry before putting it back in. Put the metering unit back together. The rubber belt should be placed back in the right direction, or your meter will malfunction. You can lubricate with graphite (NO OIL or WD-40). It is recommended to take your finger pick-up metering unit to a dealer to have it calibrated every year or every 300-400 acres. Take a bag of your own seed with you, and give him the correct speed at which you’ll be driving. If you have a vacuum or air meter, check for leaks and appropriate vacuum or air pressure.

Planter unit. Accurate depth placement can be compromised if planter units are loose or wobbly. You should not be able to easily lift up your unit or move it sideways. Look across your planter units from the side. Are they all at the same height? If one unit is either up or down compared to the others, it needs work. A common problem is that some bolts are loose or additional bushings are needed. You also need to replace cracked or broken seed hoppers.

Seed opener disks. Seed opener disks need to have a minimum diameter (check operator manual) or they will not place the seed at the appropriate depth. Seed opener disks also need to come together in the front (they should usually touch for 3″, but this may vary depending on planter). Stick two business cards between the openers and move them as close together as possible. If opener disks are worn too much you will get a “W” shaped seed slot instead of the desired “V” slot.

Seed tubes. The end of seed tubes may wear to the extent that they curl inwards, catching seeds. There is often a hook halfway up that can easily break off. Seedtube guards need to have their minimum width and be fastened correctly or damage to the seed tube is likely.

Seed firmers. These help to press the seed down in the furrow, guaranteeing more accurate depth placement of the seeds. The tension can be adjusted with a bolt. If the seed firmers are worn too much they need to be replaced.

Depth wheels. Depth wheels should run tight against disks. Change washers from in- to outside (or vice versa) of depth wheel if necessary. If this doesn’t resolve the problem, the depth wheel arm needs to be replaced.

Coulters. Check the diameter of the coulters, and replace them if needed. You should adjust the depth of worn coulters that are still usable.

Closing wheels. Closing wheels need to have an intact spring, and need to be checked for damage or wear. Bearings cannot be wobbly or too tight. The bottoms of rubber or cast iron closing wheels need to be 1.5”-2” apart. The closing wheel arm cannot have too much play or bushings or the entire arm may need replaced.

Alignment of coulters, opener disks, and closing wheels. Take a rope and pull it straight from the front coulter to the closing wheels. The firming wheels, seed openers, and coulters should all be in line. Closing wheels should not run on top of the seed furrow.

Insecticide boxes. The insecticide boxes should have no holes or cracks. Tubes should be blown out with air as well as the slot on bottom of meter.

Fertilizer unit. Fertilizer opener disks should have a minimum diameter (check manual). The bearings should not be wobbly or too tight. Hang a bucket below the tube of the unit, and do a test run of 175 feet in the field. Weigh the fertilizer in the bucket, multiply by 100, and you have the fertilizer you’ll put on in pounds per acre (at 30″ row spacing). Adjust as needed.

Chains and sprockets. Check all chains and their sprockets. If they are worn too much they need to be replaced. They need to have the appropriate tension and should be greased regularly.

Check tire pressure.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

PLANTER SET-UP AND OPERATION IN THE FIELD

To get good results, it is important to take time to set your planter up appropriately in the field, and to make adjustments according to soil conditions. You don’t want to plant in soil that is sticky and wet. Ideal is to have crumb soil conditions. The planter needs to be level with the soil surface, as well as the parallel arms on the planter units. The units cannot be cocked forward or backward. The most common remedy is to raise or lower the hitch on the tractor. More weight may also be needed on the planter in some cases. The next step is to drop the planter in the field, tie up closing wheels and seed firmers, and make a run with the planter. Count seeds in each furrow and measure the distance between them. At 30″ row spacing, measure seeds in 17′6″ length and multiply by 1000 to get the plant population per acre dropped by that unit. Spacing between seeds should be similar. Check how deep the seeds are placed and adjust depth gauge wheel settings until it is 1.5″–2″ deep. Untie the closing wheels and seed firmer and run the planter some more. The closing wheels cannot run on top of the seed and should close the seed furrow. If this is not the case, pressure may need to be increased on the closing wheels. However, the pressure should be set as light as possible to avoid compacting soil too much above the seed. Coulters should run to seed depth, preferably not deeper. Unit down pressure springs need to be adjusted according to field conditions. Fertilizer and insectide flow rates need to be checked to make sure you apply the right amount. Chains need to be oiled daily, and depth wheel arm greased twice daily. Add one tablespoon of graphite in each hopper for each 6 bushels of seed. You may need to increase the graphite application if the seeds are insecticide coated (check seed company specs).

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

Pest Management

WHAT’S NEW FOR WEED CONTROL IN CORN

Curtail 2.38L (Dow AgroSciences) is now labeled for use in field corn. Curtail contains clopyralid (Stinger) plus 2,4-D and can be applied postemergence to control numerous broadleaves including Canada thistle. The use rate is 2 pt/A and should be applied to corn before it reaches 8 inches tall (V4 growth stage).

Impact 2.8SC (AmVac) is a new active ingredient (topramesone) that is similar to Callisto and can be used in field or sweet corn. There should be limited amounts of Impact available in 2006. Impact is an HPPD-inhibitor herbicide (pigment inhibitor) that can be applied either pre or post up to 45 days before harvest. Impact has similar broadleaf activity but increased grass activity when compared to Callisto. It controls lambsquarters, pigweed, velvetleaf, ragweed, giant foxtail, barnyardgrass, and crabgrass. However, it is not intended to be a standalone grass herbicide. The manufacturer recommends tank mixing with atrazine to improve weed control spectrum and optimize efficacy. We evaluated Impact applied early to mid Post in two trials over the last 2 years at Rock Springs. In tank mixture with 0.5 to 1.0 lb atrazine, Impact effectively controlled the broadleaf weeds in our trial (TR lambsquarters, common ragweed, and velvetleaf). We do not have much experience with its grass activity. The typical use rate is 0.5 to 1 fl oz/A and the spray solution must include either COC or MSO + UAN. Do not tank mix with mesotrione (Callisto) or isoxaflutole (Balance) or crop injury may occur. Small grains can be planted 3 months after application and soybean and alfalfa after 9 months. We do not have rotational crop experience with Impact, but have understanding that herbicide carryover and subsequent crop injury may be an issue in certain areas with sensitive crops. More details will be provided as we learn more about this product and the label guidelines.

Lumax 3.95SC (Syngenta) is now labeled for use in sweet corn. Lumax must be applied preemergence in sweet corn, otherwise crop injury may occur if applied after emergence. The use rates are similar to those used in field corn, 2.5 qt/A on soils with <3% organic matter and 3 qt/A on soils with >3% organic matter. Camix (s-metolachlor + mesotrione) has also received a label for preemergence use in sweet corn. However, Lexar has not yet received a sweet corn use label. Callisto can be applied either pre or post to sweet corn.

Radius 4SC (Bayer CropScience) is a premix that contains isoxaflutole (Balance Pro) and flufenacet (Define). It is similar to Epic but contains a different ratio of the active ingredients (less Balance and more Define). Atrazine is a logical tank mix product to increase the control spectrum of Radius. Radius must be applied pre and before corn emergence. The medium soil rate range is 12 to 22 fl oz/A. We tested Radius at 19 fl oz/A (equals 2 fl oz Balance Pro + 17 fl oz Define) this past season at both Landisville and Rock Springs. Radius controls a number of common broadleaf and grassy weeds including lambsquarters and pigweed (both triazine- and ALS-resistant), velvetleaf, ragweed, smartweed, black nightshade, foxtails, crabgrass, and fall panicum. It is weak on yellow nutsedge, cocklebur, and annual morningglory. Radius will be available for the 2006 growing season and Epic will be phased out over time.

Resolve 25DF (DuPont) contains the single active ingredient, rimsulfuron, which is a component found in Steadfast and Basis. Resolve can be applied at a rate of 0.5 to 2 oz/A. It can be tank mixed with full or reduced rates of most registered corn herbicides. Certain tank mixtures, such as Resolve plus atrazine and Balance Pro applied pre, have provided good weed control in some studies. Resolve can be applied post to corn up to 12 inches tall or the 6-collar growth stage. When applied post, it is primarily targeted for use as a tank mix partner with glyphosate products in Roundup Ready corn systems to improve control of certain annual weeds and provide some residual activity. Wheat can be planted 4 months after application and soybean, alfalfa, sweet corn, and snap beans after 10 months.

Stout 72.5DF (DuPont) contains nicosulfuron (Accent) and thifensulfuron (Harmony GT) and controls several annual grassy and broadleaf weeds in field corn. The Stout label will allow for applications to corn up to 16 inches tall (V5 stage) at a rate of 0.5 to 0.75 oz/A plus surfactants. Tank mixtures will be allowed and the crop rotations restrictions will be similar to those on the Accent label. Stout will be positioned to compete with Option for resprays on field corn and should be available for the 2006 growing season.

Dwight Lingenfelter, dxl18@psu.edu and
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

WHAT’S NEW FOR WEED CONTROL IN SOYBEANS

Canopy 75DF (DuPont) is making a comeback. Canopy is a premix of chlorimuron (Classic) and metribuzin (Sencor) which provides good control of many annual broadleaves including, lambsquarters, pigweed, smartweed, velvetleaf, cocklebur, jimsonweed, prickly sida, and common ragweed. Canopy must be applied pre and at a rate range of 2.25 to 7 oz/A. Some changes to the new label include, adjusted U.S. regions to provide better recommendations for use rates and rotation restrictions, updated list of tank mix options, and added some more species to the list of weeds controlled. Otherwise, Canopy can be used like it was in the past.

Canopy EX 29.5DF (DuPont) is a premix of chlorimuron (Classic) and tribenuron (Express). It will be primarily used for fall or early spring burndown and some residual control of common winter annual weeds prior to planting soybeans in no-till or conservation tillage fields. Canopy EX can be applied from 1.1 to 3.3 oz/A and the spray solution must include either COC or NIS. For best burndown results, the addition of 2,4-D ester is recommended. It will provide control of numerous winter weeds including common chickweed, purple deadnettle, henbit, shepherdspurse, yellow rocket, pepperweed, bittercress, speedwell, and dandelion. For fall treatments, apply anytime after early October while weeds are still actively growing but before ground becomes frozen. Do not apply Canopy EX within 45 days of soybean planting. Be cautious of crop rotation restrictions – 3 months for small grains and pasture grasses, 9 months for field corn and sorghum, 12 months for alfalfa and clovers, and 18 months for sweet corn. With the introduction of Canopy EX, DuPont has phased out Canopy XL [chlorimuron + sulfentrazone (Authority)].

Select Max 0.97EC (Valent) is a new clethodim product which has some new adjuvants in the formulation which improve grass control compared to the old Select formulation. Although it controls many annual and perennial grasses, its primary use will be in Roundup Ready soybeans to control volunteer Roundup Ready corn varieties. Use 8 to 12 fl oz/A for volunteer corn from 4 to 24 inches tall. No additional surfactants are needed if it is tank-mixed with a glyphosate product that is already fully loaded with adjuvants. Select Max will initially be marketed in the Midwest, however some may eventually be here in the Northeast.

Synchrony XP 28.4DF (DuPont), a premix of chlorimuron (Classic) and thifensulfuron (Harmony GT), got a major label overhaul. Some changes include, better defined uses and restrictions of Synchrony XP in STS and non-STS soybeans, updated information on its use as a spring burndown and/or preemergence treatment, modified rate changes, weed claims, and tank mixture options. Plus DuPont updated section headers, table of contents, and general text to improve clarity and make the label easier to use.

Dwight Lingenfelter, dxl18@psu.edu and
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

WHAT’S NEW FOR WEED CONTROL IN SMALL GRAINS

Axial 0.834L (Syngenta) is a new, unique ACCase-inhibitor herbicide containing pinoxaden that controls foxtails, annual ryegrass, barnyardgrass, and volunteer oats in wheat and barley. It does not control downy brome, annual bluegrass or quackgrass. It has a wide window of application and can be tank mixed with other small grain herbicides.

Osprey 4.5WDG (Bayer CropScience) Osprey is an ALS-inhibitor herbicide that contains mesosulfuron. Osprey is labeled for use in wheat and in our region it will be primarily targeted for control of annual ryegrass, including Hoelon (ACCase) resistant biotypes. It does have activity on annual bluegrass and will suppress common chickweed, henbit, and pigweed. The Osprey use rate is 4.75 oz/A. The Osprey label was recently revised and includes some additional language such as concern for crop injury when frost occurs shortly after application to the actively growing wheat. Some additional changes include simplifying adjuvant recommendations and stating to always include a non ionic surfactant (NIS) plus an ammonium nitrogen fertilizer or MSO (methylated seed oil) or a “basic blend” type adjuvant. The application in fluid fertilizer section was also clarified and states that Osprey may be applied using liquid nitrogen solution as the carrier. The fertilizer spray solution should not exceed 15% liquid nitrogen and NIS should be added at no more than 0.25% v/v. Osprey may be tank-mixed with other herbicides including, Harmony Extra, Harmony GT, MCPA, Buctril, and Stinger. Soybeans can be planted 90 days after application, alfalfa after 10 months, and corn after 12 months. Side note: Aside from Osprey, Achieve and Hoelon are other herbicide options to consider for annual ryegrass control. Hoelon has been labeled for use in wheat and barley to control annual ryegrass and other weedy grasses, but is not effective on downy brome or cheat. Hoelon may be applied pre or post in wheat, but only pre in barley. Achieve provides good control (90%) but must be applied early, before annual ryegrass reaches 1 inch tall. Applications made after this time provided poorer control. Hoelon and Achieve will not control ACCase-resistant ryegrass, which has been a problem in Maryland and Virginia.

Dwight Lingenfelter, dxl18@psu.edu and
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

WHAT’S NEW FOR WEED CONTROL: PASTURE, CRP AND MISCELLANEOUS

Milestone 2L and ForeFront R&P (Dow AgroSciences) are pasture herbicides containing a new active ingredient called aminopyralid. Milestone is the single active ingredient and ForeFront R&P also contains 2,4-D. Both products will be marketed for pasture and CRP. Aminopyralid is a plant growth regulator and specifically a pyridine related to clopyralid (Stinger) and triclopyr (Garlon). Aminopyralid is a new generation active ingredient that is effective at low rates compared to similar herbicides. Typical pasture use rates for aminopyralid is 1 to 1.75 oz active ingredient per acre (4 to 7 oz Milestone). Some of the other benefits include very low toxicity to birds, fish, mammals and aquatic invertebrates, non volatile, no grazing restrictions, and it is NOT a restricted use pesticide. Milestone a broadleaf herbicide that provides systemic control of several problem weeds including most thistles, dock species, and solanaceous weeds (e.g. horsenettle) to name just a few. Penn State has tested the herbicide for two seasons in pasture and would characterize it as a fairly broad spectrum product with some residual control with good forage grass safety. Additional products containing aminopyralid will also be available for wheat and barley. You will certainly hear more about this active ingredient as it becomes available.

Outrider 75WDG (Monsanto) contains sulfosulfuron and is labeled for postemergence use in noncrop areas including CRP and native, warm season perennial grasses. The use rate range is 0.75 to 2 oz/A plus a surfactant. Outrider can be used to control numerous annual and perennial weeds including, downy brome, buttercup, chickweed, horseweed, Johnsongrass, mustard spp., ragweed, smartweed, quackgrass, and yellow nutsedge. Be cautious of rotation restrictions since many crops cannot be planted for up to 22 months after application.

Other Products

Gramoxone Inteon 2L (Syngenta) is a new formation of Gramoxone (paraquat) that includes the new “Inteon Technology”. According to Syngenta, this new technology provides added safety measures and a 10X reduction in oral toxicity by including a special safening agent that is derived from a seaweed extract called “alginate”. The pesticide forms a gel when it comes in contact with acid pH (1 to 3) typically found in the stomach. This slows dispersion of the pesticide into the small intestine allowing the emetic to act. Gramoxone Inteon is a slightly thicker consistency than Gramoxone Max, the odor is less offensive, and it is a 2 lb/gal formulation. So, 2 pt/acre of Gramoxone Max is equivalent to 3 pt/acre of the new Gramoxone Inteon formulation. This product has been tested by the industry and universities and performance indicative of other Gramoxone products was observed.

Pending Products

Autumn WDG (Bayer CropScience) contains iodosulfuron, an active ingredient in Equip. Autumn will be primarily used as a fall burndown product before corn to control winter annual weeds.

KIH-485 (Kumiai) is a new, experimental compound for corn that has activity similar to chloroacetamide (e.g., Dual, Harness) and dinitroanaline (e.g., Prowl) herbicides but has a completely different chemical structure. It seems to have a slightly longer residual activity than the chloroacetamides and has good activity on the common broadleaf and grassy weeds found in Pennsylvania’s corn fields. It has a low use rate ranging from about 3 to 8 oz/A. KIH-485 has been tested at the industry and university level since 2003. If development of this compound continues, it would compete in the same market as the pre-grass + atrazine products such as Bicep, Harness Xtra, Keystone, Guardsman, etc. There has yet to be a tradename selected or date set for commercial sales of this herbicide.

Other News — GLYPHOSATE ISSUES

Roundup Ready alfalfa varieties have been approved for use by USDA and will allow over-the-top applications of glyphosate. Seed supplies will be limited initially, but there should be some fall dormancy 3 and 4 varieties for our area. The seed cost will likely be about double the cost of a normal bag of seed which includes a technology fee ($125/bag) and producers will need to sign a Technology Agreement. Yield and quality data are being tested at universities and other industries and so far they are similar to normal varieties. Penn State is still testing RR alfalfa for performance, yield, and other considerations such as opportunities in no-till and potential use in mixed stands.

Glyphosate stewardship is still a major focus of universities, weed science societies, and industries to preserve the usefulness of glyphosate. Since companies are not discovering and producing as many herbicides as in the past, we need to preserve the ones that are currently available. Therefore, proper management of glyphosate and other herbicides is critical for their continued usefulness in the future. Certain management practices are being recommended to avoid the development of glyphosate resistant weed populations. Some recommendations include: rotating glyphosate with non-glyphosate herbicides; if possible, not using more than two applications of a glyphosate-based herbicide in a field over a two-year period; using tank mixtures or alternative herbicides for burndown in RR crops that require more than one over-the-top glyphosate application; planting conventional rotational crops following RR crops and using non-glyphosate herbicides; and following good crop management practices to ensure competitive crops and including non-chemical weed control tactics when possible.

Dwight Lingenfelter, dxl18@psu.edu and
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

GRASS CONTROL IN WHEAT AND BARLEY

Dense populations of winter annual weeds can compete with wheat in early spring and slow the rate of crop development. Herbicides should be applied soon to minimize the impact of these types of weed populations on the wheat. However, herbicides will be most effective where it is readily apparent that plants have resumed active growth. Winter annual grasses, such as downy brome, cheat, annual bluegrass, and annual ryegrass, should be controlled as soon as an inch of new growth has occurred. The wheat herbicides available for control of grasses, Maverick, Osprey, and Olympus, are most effective when applied in the fall, and effective spring activity is dependent upon the weeds being small. Be sure to follow label guidelines to minimize risk of crop injury and yield loss. Labels for some products specify the number of tillers or leaves that wheat should have before treatment is allowed. Also, be cautious of crop rotation intervals, certain herbicides such as Olympus and Maverick have long recrop intervals for typical cropping systems in the northeast.

Table 1. Effect of herbicides on selected weedy grasses in wheat*
Herbicide Control Suppression
(* Achieve, Finesse, and Hoelon can be applied to barley.)
Achieve
  • annual ryegrass
  • foxtail spp.
  
Everest
  • annual ryegrass
  • cheat
  • foxtail spp.
  • downy brome
Finesse  
  • annual bluegrass (fall)
  • annual ryegrass (fall)
  • downy brome (fall)
  • cheat (fall)
[control of these species can be obtained depending on rate and timing.]
Hoelon
  • annual ryegrass
  • crabgrass
  • foxtail spp.
  
Maverick
  • downy brome (fall)
  • cheat (fall)
  • chess (fall)
  • downy brome (spring)
  • cheat (spring)
  • chess (spring)
  • quackgrass
  • annual ryegrass
Olympus
  • downy brome (fall)
  • cheat
  • chess
  • downy brome (spring)
  • quackgrass
Olympus Flex
  • annual ryegrass
  • annual bluegrass
  • cheat
  • downy brome (fall)
  • downy brome (spring)
  • quackgrass
Osprey
  • annual ryegrass
  • annual bluegrass
  • downy brome
  • chess

Dwight Lingenfelter, dxl18@psu.edu and
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

SOME GENERAL RULES ABOUT GRAMOXONE AND GLYPHOSATE BURNDOWN

Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences