Botany Commons^™

Field Evaluation Of Herbicides On Vegetables And Small Fruits 2004, Ronald E. Talbert, Colleen M. Thomas, Brian V. Ottis, Andrew T. Ellis

Arkansas Agricultural Experiment Station Research Series

Herbicide evaluation studies on vegetables and small fruits were conducted in 2004 at the Arkansas Agricultural Experiment Station at Fayetteville, AR, in an effort to evaluate new herbicides, herbicide mixtures, and their application timings for weed control efficacy and crop tolerance. Results of these studies, in part, provide useful information to producers, fellow researchers, the Crop Protection Industry, and the IR-4 Minor Crop Pest Management Program in the development of potential new herbicide uses in vegetable, and fruit.

Field Evaluation Of Herbicides On Rice 2004, Brian V. Ottis, Ronald E. Talbert, Andrew T. Ellis

Arkansas Agricultural Experiment Station Research Series

Herbicide evaluation studies on rice were conducted in 2004 at the Rice Research and Extension Center near Stuttgart, AR, in an effort to evaluate new herbicides, herbicide mixtures, and their application timings for weed control and crop tolerance. Results of these studies, in part, provide useful information to producers, fellow researchers, and the Crop Protection Industry for the potential use of new herbicide programs for successful rice production in Arkansas.

The Quintessential Companion For North American Birders: Review Of The Birdwatcher's Companion To North American Birdlife By Christopher W. Leahy, Lawrence Igl

The Prairie Naturalist

The Birdwatcher's Companion was revised in 2004 under a new title, The Birdwatcher's Companion to North American Birdlire, and by a new publisher, Princeton University Press. This substantial work builds on Leahy's previous edition published in 1982. Hailed by the publisher as the quintessential, alphabetically arranged guide to North American birdlife, the new edition of The Birdwatcher's Companion is over 100 pages longer than the first edition, but, overall, the style and format have not changed much between the two editions. The Companion begins with a brief chapter in which the author describes how to use the book, how it …

Factors Influencing Persistence Of White-Footed Mice, Brock R. Mcmillan, Glennis A. Kaufman, Donald W. Kaufman

The Prairie Naturalist

We examined factors that potentially influenced persistence of the white-footed mouse (Peromyscus leucopus) during 1981 to 1988 at Konza Prairie Biological Station, Kansas. We predicted that both abiotic (e.g., precipitation and temperature) and biotic (e.g., availability of food and density of conspecifics) factors would influence persisten~e of individuals at the study site. Persistence of individual white-footed mice on the study site differed among years and seasons. White-footed mice that were first captured in summer or in autumn persisted longer than those first captured in spring. Young females (less than 20 g) had greater persistence than young males, whereas …

Lack Of Brown-Headed Cowbird Nest Parasitism In A Short Grass Region, Stephen L. Winter, Jack F. Cully Jr.

The Prairie Naturalist

While conducting field work in Morton County, southwestern Kansas and Baca County, southeastern Colorado, during the period 27 May to 2 July 1997, we found 36 nests of seven bird species. Nests were not searched for systematically, but were found coincidentally as data were collected along transects during research investigating the breeding bird and plant communities of black-tailed prairie dog (Cynomys ludovicianus) colonies and noncolonized shortgrass prairie (Winter 1999).

Low densities of the brown-headed cowbird in our study region, which is characterized by a semi-arid climate, might be a consequence of host populations that exhibit extreme temporal and …

Comparison Of Microclimate At Grassland Bird Nests With Different Substrates, Kimberly M. Suedkamp Wells, Samuel D. Fuhlendore

The Prairie Naturalist

We compared the effects of two different nest placement strategies (shrubs vs. bunchgrasses) on microclimate conditions for grasshopper sparrow (Ammodramus savannarum) and lark sparrow (Chondestes grammacus) in Oklahoma. We predicted that the intensity and duration of extreme temperatures (greater than 39° C) and their variability would be reduced at shrub nests compared to bunchgrass nests. A verage maximum temperatures were similar at nests of grasshopper sparrow and lark sparrow, but confidence intervals were more variable and included biologically detrimental temperatures at grasshopper sparrow nests compared to lark sparrow nests. The proportion of time greater than 39° …

The Sooner State Bird Atlas: Review Of Oklahoma Breeding Bird Atlas, Dan L. Reinking, Editor, Timothy J. O'Connell

The Prairie Naturalist

In Oklahoma, forest meets prairie, prairie meets mesa, and throughout, our native ecosystems are shaped by human land use. Across this shifting mosaic of habitats, animals find food, raise young, and disperse to find other members of their species. Management for these species is best informed when it springs from a common baseline of knowledge about distributions across the entire management area. For birds, that baseline can be effectively established with a breeding bird atlas. ... In sum, the Oklahoma Breeding Bird Atlas presents timely information on a fascinating statewide avifauna in a clear and attractive package. The text is …

Daphnia Lumholtzi, An Exotic Zooplankton, Invading A Nebraska Reservoir, Brian C. Peterson, Nicolas J. Fryda, Keith D. Koupal, Wyatt Hoback

The Prairie Naturalist

A limnological assessment project by the University of Nebraska at Kearney and the Nebraska Game and Parks Commission collected weekly vertical zooplankton tows during May through September 2002 at Harlan County Reservoir in Nebraska. Beginning on 5 August 2002, the exotic Daphnia lumholtzi (Cladocera: Daphniidae) appeared at a density of 0.04 1.1 in one of fifteen standardized sampling stations. By 6 September 2002, D. lumholtzi was found in all fifteen stations at an average density of 2.17 ± 3.10 1.1 with a site maximum density of 11.43 1.1 • Length measurements of D. lumholtzi ranged from 0.80 mm to 5.66 …

Electrocution Of An Adult White-Tailed Deer, Christopher S. Deperno, Benjamin J. Bigalke, Jonathan A. Jenks, Brian S. Haroldson, Robert G. Osborn

The Prairie Naturalist

On 16 May 2002, an adult female white-tailed deer (Odocoileus virginianus) died after becoming entangled in an electric fence in southeast Minnesota. The deer (#393) was captured 30 January 2000 as part of a cooperative, long-term deer mortality study being conducted in southern Minnesota (Bigalke et al. 2002, Brinkman 2003, Brinkman et al. 2002). Although fence entanglements occur, they do not account for significant losses in white-tailed deer populations (Matschke et al. 1984). Nixon et al. (1991) documented mortality of two fawns with broken cervical vertebrae that had collided with fences, but did not distinguish the type of …

Continued Range Expansion Ny The Cave Myotis, Shauna R. Marquardt, Jerry R. Choate, Stanley D. Roth Jr.

The Prairie Naturalist

The cave myotis (Myotis velifer) is a cavernicolous bat that ranges northward from Honduras to the southern Great Plains and southwestern United States. Its known range in the United States includes the states of Kansas, Oklahoma, Texas, Arizona, New Mexico, and small, southern portions of Nevada and California (Fitch et al. 1981, Hayward 1970). The cave Myotis inhabits caves, mines, and buildings, depending on time of year and specific roost requirements (Fitch et al. 1981, Hayward 1970, Kunz 1973, Sparks and Choate 2000). Before European settlement of areas within the range of the cave Myotis, it likely …

The Prairie Naturalist, Volume 37, No. 1, March 2005

The Prairie Naturalist

LESSER PRAIRIE-CHICKEN USE OF HARVESTED CORN FIELDS DURING FALL AND WINTER IN SOUTHWESTERN KANSAS, G. C. Salter, R. J. Robel, and K. E. Kemp 1

DAPHNIA LUMHOLTZI, AN EXOTIC ZOOPLANKTON, INVADING A NEBRASKA RESERVOIR B. C. Peterson, N. J. Fryda, K. D. Koupal, and W. W. Hoback 11

COMPARISON OF MICROCLIMATE AT GRASSLAND BIRD NESTS WITH DIFFERENT SUBSTRATES, K. M. Suedkamp Wells and S. D. Fuhlendorf 21

FACTORS INFLUENCING PERSISTENCE OF WHITEFOOTED MICE, B. R. McMillan, G. A. Kaufman, and D. W. Kaufman 29

NOTES

RECORDS OF THE EASTERN RED BAT ON THE NORTHERN FRONT RANGE OF COLORADO, …

Records Of The Eastern Red Bat On The Northern Front Range Of Colorado, Daniel J. Neubaum

The Prairie Naturalist

Although common in deciduous forest throughout the Midwest and east-central states, the eastern red bat (Lasiurus borealis) is rare in Colorado (Armstrong et al. 1994, Fitzgerald et al. 1994). However, this species has the potential to extend its range because belts of eastern deciduous forest habitat have expanded across western prairies and reached the Front Range of Colorado over the last 100 years (Knopf 1986). The eastern red bat ranges from Canada southward across the United States to northeastern New Mexico with most records occurring east of the Continental Divide (Hall 1981, Shump and Shump 1982, Cryan 2003). …

Lesser Prairie-Chicken Use Of Harvested Corn Fields During Fall And Winter In Southwestern Kansas, Gregory C. Salter, Robert J. Robel, Kenneth E. Kemp

The Prairie Naturalist

The lesser prairie-chicken (Tympanuchus pallidicinctus) has declined in numbers in Kansas primarily due to the conversion of sand sagebrush (Artemisia .filifolia) prairie to cropland. The lesser prairie-chicken in Finney County, Kansas exists primarily in large fragments of sand sagebrush prairie, and it forages during fall and winter on waste grain in harvested com (Zea mays) fields adjacent to prairie fragments. We used radio-telemetry to monitor lesser prairie chicken locations and found no significant relationship between numbers of bird locations and amounts of waste grain on the ground in harvested com fields. Even the harvested …

First Record Of An Adult Male Evening Bat From Kansas, Clay R. Davis, Justin G. Boyles

The Prairie Naturalist

The evening bat (Nycticeius humeralis) occurs throughout the eastern and southeastern United States and into extreme northeastern Mexico, approximately 42° to 18° N latitude (Watkins and Shump 1981). Although records of females are common, records of adult male evening bats are rare in the northern portion of the species range (Watkins 1969, Watkins 1972). Jones et al. (1967) suggested that adult males might not accompany females to at least some parts of the parturient range. As part of a larger study (Davis 2003) we surveyed bats on Fort Leavenworth Military Reservation (FLMR), Leavenworth County, Kansas in July 2002 …

The Prairie Naturalist Volume 36, No.4 December 2004

The Prairie Naturalist

ROADSIDE BIAS IN POINT COUNT SURVEYS AT ARROWWOOD NATIONAL WILDLIFE REFUGE, NORTH DAKOTA ▪ J. S. Dieni and P. Scherr

HISTORY OF GREATER SAGE-GROUSE IN THE DAKOTAS: DISTRIBUTION AND POPULATION TRENDS ▪ . J. T. Smith, L. D. Flake, K. F. Higgins, and G. D. Kobriger

PATCH USE BY A MONOPHAGOUS HERBIVORE IN FRAGMENTED PRAIRIE LANDSCAPES ▪ . M. J. St. Pierre and S. D. Hendrix

SNOWSHOE HARE OCCURRENCE AND WINTER HABITAT ON THE MISSOURI COTEAU IN NORTH DAKOTA ▪ R. K. Murphy 243

HIGH ABUNDANCE OF NESTING LONG-EARED OWLS IN NORTH DAKOTA ▪ R. K. Murphy, L. J. Rosenfield, …

The Prairie Naturalist Volume 36, No.3 September 2004

The Prairie Naturalist

OVERLAND MOVEMENTS AND HABITAT USE OF MALLARD BROODS DEPARTING OVERWATER NESTING STRUCTURES ▪ J. D. Stafford, L. D. Flake, and P. W. Mammenga

NEST SITE CHARACTERISTICS OF EASTERN WILD TURKEY IN NORTHEASTERN SOUTH DAKOTA ▪ R. D. Shields and L. D. Flake

WHITE-TAILED DEER INFECTEUWITH STAPHYLOCOCCUS HYICUS IN SOUTH DAKOTA ▪ T. J. Zimmerman, J. A. Jenks, and A. E. Pillatzki

CLOSTRIDIUM PERFRINGENS TYPE A IN A FREE-RANGING FAWN? ▪ T. J. Brinkman, J. A. Jenks, C. S. DePerno, and B. S. Haroldson

BUFFLEHEAD BREEDING ACTIVITY IN SOUTH-CENTRAL NORTH DAKOTA ▪ G. A. Knutsen and J. C. King

POTENTIAL MULTIPLE …

The Prairie Naturalist Volume 36, No.2 June 2004

The Prairie Naturalist

PREDICTING NEONATAL AGE OF WHITE-TAILED DEER IN THE NORTHERN GREAT PLAINS . . T. J. Brinkman, K. L. Monteith, J. A. Jenks, and C. S. DePemo

DUCK NESTING ON ROTATIONAL AND CONTINUOUS GRAZED PASTURES IN NORTH DAKOTA . R. K. Murphy, D. J. Schindler, and R. D. Crawford

MORPHOLOGY OF LESSER PRAIRIE-CHICKENS IN KANSAS ▪ C. A. Hagen, J. C. Pitman, R. J. Robel, and R. D. Applegate

DAILY AND SEASONAL BEHAVIOR OF BISON ON AN OKLAHOMA TALLGRASS PRAIRIE . E. J. Maichak, K. L. Schuler, and M. E. Payton

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA 2003 ▪ R. N. …

Field Evaluation Of Herbicides On Rice 2003, Ronald E. Talbert, Brian V. Ottis, Mayank S. Malik, Andrew T. Ellis

Arkansas Agricultural Experiment Station Research Series

Herbicide evaluation studies on rice were conducted in 2003 at the Rice Research and Extension Center near Stuttgart, Ark., in an effort to evaluate new herbicides, herbicide mixtures, and their application timings for weed control efficacy and crop tolerance. Results of these studies, in part, provide useful information to producers, fellow researchers, and the crop protection industry for the potential use of new herbicide programs for successful rice production in Arkansas.

The Prairie Naturalist Volume 36, No.1 March 2004

The Prairie Naturalist

DUCK NESTING SUCCESS IN NORTH DAKOTA ROAD RIGHT-OF-WAYS ▪ J. Walker, S. S. Stephens, M. S. Lindberg, and J. 1. Rotella

DID TALLGRASS PRAIRIE EXTEND INTO PENNSYLVANIA? ▪ D. C. Laughlin

INFLUENCE OF PREY ABUNDANCE ON RAPTORS IN TALLGRASS PRAIRIE ▪ A. W. Reed, G. A. Kaufman, D. A. Rintoul, and D. W. Kaufman

AMERICAN BITTERN NESTING IN THE SAN JOAQUIN VALLEY, CALIFORNIA ▪ L. C. Carroll and F. A. de Szalay

THE FLORA OF THE COTTONWOOD LAKE STUDY AREA, STUTSMAN COUNTY, NORTH DAKOTA ▪ . D. M. Mushet, N. H. Euliss Jr., S. P. Lane, and C. M. Goldade …

The Prairie Naturalist Volume 35, No.4 December 2003

The Prairie Naturalist

HOME RANGE AND MOVEMENTS OF EASTERN AND RIO GRANDE WILD TURKEY FEMALES IN NORTHEASTERN

SOUTH DAKOTA ▪ C. P. Lehman, L. D. Flake, and A. P. Leif

THE BAT FAUNA OF SOUTHEASTERN SOUTH DAKOTA . J. E. Lane, C. L. Buck, and R. M. Brigham

FIRST REPORT OF THE NORTH DAKOTA RARE BIRD COMMITTEE ▪ D. Svingen and R. E. Martin

BREEDING CHRONOLOGY OF DABBLING DUCKS IN MINNEDOSA, MANITOBA ▪ A. M. Wells and H. H. Prince

A LIVE COLLECTION OF A PISTOLGRIP FROM NEBRASKA ▪ S. C. Schainost

NEW NESTING DATES FOR SOME BREEDING BIRDS IN NORTH DAKOTA ▪ …

Integrated Weed Management Plan For The Lower Las Vegas Wash, Elizabeth Bickmore

Publications (WR)

The Las Vegas Wash (Wash) is the primary drainage for the metropolitan Las Vegas Valley, eventually finding its way into the Colorado River watershed system. Pursuant to the recommendations of the Water Quality Citizens Advisory Committee, the Las Vegas Wash Coordination Committee (LVWCC) was formed in 1998 to develop a comprehensive plan for the long-term stabilization and management of the Wash. Consisting of representatives from 28 government agencies, businesses, environmental groups and citizens, the LVWCC formulated the Las Vegas Wash Comprehensive Adaptive Management Plan (CAMP) and designated the Southern Nevada Water Authority (SNWA) as the lead agency for the implementation …

The Prairie Naturalist Volume 35, No.3 September 2003

The Prairie Naturalist

BROWN-HEADED COWBIRDS IN GRASSLANDS: THEIR HABITATS, HOSTS, AND RESPONSE TO MANAGEMENT ▪ J. A. Shaffer, C. M. Goldade, M. F. Dinkins, D. H. Johnson, L. D. Igl, and B. R. Euliss

LlGUMIA SUBROSTRATA (BIVALVIA: UNIONIDAE) IN MINNESOTA AND ITS STATUS IN THE UPPER MIDWEST ▪ B. E. Sietman, D. E. Kelner, R. A. Hart, and M. Davis

GUIDELINES FOR FINDING NESTS OF PASSERINE BIRDS IN TALLGRASS PRAIRIE ▪ M. Winter, S. E. Hawks, J. A. Shaffer, and D. H. Johnson

RESPONSE OF THE LEAST SHREW TO PREY OLFACTORY CUES ▪ F. Punzo and C. Gonzalez

Book Reviews

North Dakota's Butterflies …

The Prairie Naturalist Volume 35, No.2 June 2003

The Prairie Naturalist

NEST PARASITISM ON CONSTRUCTED ISLANDS IN NORTHWESTERN NORTH DAKOTA ▪ A. L. Zimmerman, M. A. Sovada, T. K. Kessler, and R. K. Murphy

HISTORICAL AND RECENT RECORDS AND FIRST NEST RECORDS OF HENSLOW'S SPARROW IN NORTH DAKOTA ▪ J. A. Shaffer, L. D. Igl, and F. Vanhove

AMERICAN AVOCET NESTING ON CONSTRUCTED ISLANDS IN NORTH DAKOTA ▪ A. L. Dahl, D. H. Johnson, L. D. Igl, K. L. Baer, T. L. Shaffer, M. A. Johnson, and R. E. Reynolds

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA 2002 ▪ R. N. Randall

MATERNAL LIVER AND EGG THIAMINE CONCENTRATIONS IN CHINOOK SALMON FROM …

A Bt Transgene Reduces Herbivory And Enhances Fecundity In Wild Sunflowers, A. A. Snow, Diana Pilson, L. H. Rieseberg, M. J. Paulsen, N. Pleskac, M. R. Reagon, D. E. Wolf, S. M. Selbo

Diana Pilson Publications

Gene flow from transgenic crops can introduce novel traits into related species, but the ecological importance of this process is unknown. Here, we report the first empirical evidence that wild plants can benefit from a bacterial transgene under uncaged, natural conditions. Cultivated sunflower (Helianthus annuus) is known to hybridize frequently with wild sunflower (H. annuus) in the western and midwestern United States. We studied a crop-developed Bacillus thuringiensis (Bt) transgene, cry1Ac, in backcrossed wild sunflower populations. Lepidopteran damage on transgenic plants was strongly reduced relative to control plants at our two study sites, while damage …

The Prairie Naturalist Volume 35, No.1 March 2003

The Prairie Naturalist

PATTERNS OF IMPALING IN A MIGRATORY POPULATION OF THE LOGGERHEAD SHRIKE ▪ J. D. Esely and E. K. Bollinger

COMPARISON OF FEEDING IN TWO PHENOLOGICALLY DISTINCT GRASSHOPPERS ▪ K. J. Haynes

DISTRIBUTION AND TRENDS OF BANDED CANADA GEESE IN SOUTH DAKOTA ▪ J. S. Gleason, J. A. Jenks, and P. W. Mammenga

FLORISTIC ASSESSMENT OF SAND PRAIRIES AND SEDGE MEADOWS, LEE COUNTY, ILLINOIS ▪ W. C. Handel, L. R. Phillippe, and J. E. Ebinger

POULT PROTECTION BY MERRIAM'S TURKEY FEMALES TOWARDS A NORTHERN GOSHAWK ▪ C. P. Lehman

ADDITIONAL ECTOPARASITIC RECORDS OF BATS FROM KANSAS ▪ D. W. Sparks, K. …

The Prairie Naturalist Volume 34, No. 3/4 September/December 2002

The Prairie Naturalist

SEASONAL FOOD HABITS OF COYOTES IN NORTHEASTERN KANSAS ▪ J. F. Kamler, P. S. Gipson, and C. C. Perchellet

SELECTION OF NESTING HABITAT BY SHARP-TAILED GROUSE IN THE NEBRASKA SANDHILLS ▪ B. L. Prose, B. S. Cade, and D. Hein

PATTERNS OF REPRODUCTION FOR WESTERN HARVEST MICE IN NORTH-CENTRAL KANSAS ▪ J. R. Goheen, G. A. Kaufman, and D. W. Kaufman

THE IMPACT OF RECREATIONAL TRAILS AND GRAZING ON SMALL MAMMALS IN THE COLORADO PIEDMONT ▪ C. A. Meaney, A. K. Ruggles, N. W. Clippinger, and B. C. Lubow

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA 2001 ▪ R. N. Randall …

The Prairie Naturalist Volume 34, No. 1/2 March/June 2002

The Prairie Naturalist

LOCALIZED MOVEMENTS AND SITE FIDELITY OF WHITETAILED DEER IN THE NORTHERN GREAT PLAINS ▪ B. J. Kernohan, J. A. Jenks, and D. E. Naugle

SPAWNING-SEASON HOMING OF COMMON CARP AND RIVER CARPSUCKER ▪ J. L. Bonneau and D. L. Scamecchia

HOME RANGES OF RING-NECKED PHEASANTS IN NORTHWESTERN KANSAS ▪ R. D. Applegate, B. E. Flock, P. S. Gipson, M. W. McCoy, and K. E. Kemp

RESPONSES OF BIGHORN SHEEP TO DISTURBANCE IN LOW-ELEVATION GRASSLANDS ▪ R. W. Sayre, R. W. Seabloom, and W. F. Jensen

DISTRIBUTION OF CHANNEL CATFISH LIFE STAGES IN A PRAIRIE RIVER BASIN ▪ . J. C. …

Compensation For Herbivory In Wild Sunflower: Response To Simulated Damage By The Head-Clipping Weevil, Diana Pilson, Karin L. Decker

Diana Pilson Publications

Herbivore damage is generally detrimental to plant fitness, and the evolutionary response of plant populations to damage can involve either increased resistance or increased tolerance. While characters that contribute to resistance, such as secondary chemicals and trichomes, are relatively well understood, characters that contribute to a plant’s ability to tolerate damage have received much less attention. Using Helianthus annuus (wild sunflower) and simulated damage of Haplorhynchites aeneus (head-clipping weevil) as a model system, we examined morphological characters and developmental processes that contribute to compensatory ability. We performed a factorial experiment that included three levels of damage (none, the first two, …

The Prairie Naturalist Volume 33, No.4 December 2001

The Prairie Naturalist

SPECIES, SEASON, AND DENSITY OF BURIED SEEDS SURVIVING FOX SQUIRREL DEPREDATION ▪ C. C. Smith, and J. M. Briggs

RELATI0NSHIP OF HYDROLOGICAL CONDITIONS AND POPULATlONS OF BREEDING PIPING PLOVERS ▪ D. S. Licht,

DEMODICOSIS IN A WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) IN SOUTH DAKOTA ▪ C. N. Jacques, J. A Jenks. M. B. Hildreth. R. J. Schauer, and D. D. Johnson

SURVEYS OF CALLING AMPHIBIANS IN NORTH DAKOTA ▪ D. H. Johnson, and R. D. Batie

EFFECTS OF HUMAN PRESENCE ON VOCALIZATIONS OF GRASSLAND BIRDS IN KANSAS ▪ S. L Bye, R. J. Robel, and K. E. Kemp

Reviewers 2001

Author …

Herbicide Evaluation In Arkansas Cotton 2000, Marilyn Mcclelland, Jim Barrentine, Ken Smith, Nilda Burgos

Arkansas Agricultural Experiment Station Research Series

Herbicidal weed control is economically important for production of cotton. Field experiments are conducted annually in Arkansas to evaluate the activity of developmental and commercial herbicides for selective control of weeds in cotton. These experiments serve both industry and Arkansas agriculture by providing information on the selectivity of herbicides still in the developmental stage and by comparing the activity of these new herbicides with that of recommended herbicides.