Grasshopper Hollow

Grasshopper Hollow

Grasshopper Hollow is the largest, most significant fen complex in unglaciated North America.

At least 15 different fen communities of various types are found at Grasshopper Hollow. A fen is a low, marsh-like area where water plays an important role in how the ecosystem functions. It is usually very wet and grassy with a variety of plant and animal species.

Why You Should Visit

This is the largest, most significant fen complex in unglaciated North America. Its wet, stony ground (in knee-deep water) is laced with beaver runs among a rich assemblage of native grasses and sedges. A spur of the Ozark Trail borders the preserve.

Why TNC Selected This Site

In this narrow, Ozark valley, at least 15 fens of various types can be found; Grasshopper Hollow has the largest known prairie fen in Missouri.

What TNC Has Done/Is Doing

In March 2000, TNC purchased the 20-acre Bryant tract, which is located within the Grasshopper Hollow watershed. This acquisition will prevent development of the site and further protect the fen communities at Grasshopper Hollow.

We are using fire management to retain the natural characteristics of a fen complex. Through a partnership with the United States Forest Service, we are restoring the fen recharge watershed. In addition, we are leasing 80 acres of the best fen habitat at the site from the Doe Run Company.


Reynolds County, SW of Centerville, MO

This preserve is on rugged, grassy terrain. The viewing platform is under repair – please do not try to access the platform.


A fall visit, when the leaves change, is perhaps the most spectacular.

Two miles south of Centerville on Highway 21, take Highway 72 west.
Approximately one mile past the Highway B intersection at Reynolds,
turn right on County Road 860 and proceed about 0.6 miles to the parking area.

What to See: Plants

Unusual wetlands fed by a permanent supply of highly mineralized groundwater. Fens and natural groundwater seepages dominate the hollow bottomlands. Among many native forbs and grasses, a visitor may find swamp agrimony, arrowleaved tear-thumb, prairie cordgrass, big bluestem, swamp aster, rough-leaf goldenrod and Michigan lily.

What to See: Animals

Notable animal species include beavers, the rare four-toed salamander and the rare wood frog. In 2000, the federally endangered Hine’s Emerald Dragonfly was discovered to be breeding at this site.

Check the local weather forecast and dress accordingly. Long pants and sleeves, hiking boots, drinking water, hat, and compass are recommended. During warm weather, light color and light-weight clothing is suggested. Repellent, binoculars, and field guide(s) are also worth bringing.

Integrated Pest Management

University of Missouri

Taking an environmentally sensitive approach to pest management

Integrated Pest & Crop Management

Wayne C. Bailey
University of Missouri
Division of Plant Sciences
(573) 882-2838
[email protected]

Grasshopper Nymphs Present in Missouri

Wayne C. Bailey
University of Missouri
(573) 882-2838
[email protected]

Published: July 27, 2009

Grasshopper nymphs can be found throughout Missouri. Typically a summer pest on field crops, the wet conditions in most areas of the state have allowed for the buildup of this pest in the lush, green vegetation of field borders, waterways, and in no-till fields. At present grasshopper nymphs range from very small in size up to 1/2 –inch in length. Wet years usually do not favor grasshopper populations as fungal pathogens can cause high mortality of small grasshoppers. This year the wet weather has not helped with grasshopper mortality, possibly allowing for grasshopper populations to build to problem levels. In Missouri, over 100 grasshopper species can be found although 6-7 species may cause problems in field crops. Typical grasshopper damage consists of irregular shaped holes extending from the leaf margin to the center of the leaf. Damaged tissue surrounding the feeding wound often has dead tissue surrounding the wound. Grasshoppers are capable of doing considerable damage in a very short time, especially at they grow in size. Adult grasshoppers (winged) are more difficult to control than smaller nymphs (wingless).

The following table lists the economic threshold for grasshopper infestations in non-cropland areas and grass pastures, corn, soybean, grain sorghum (milo) pesticide label directions and precautions.

Grasshoppers Invading Missouri Fields

Farmers should scout and, if needed, spray for grasshoppers now, said University of Missouri Extension entomologist Wayne Bailey. Grasshoppers are reported in almost every county in the state, he said.

“Numbers of small grasshoppers are exceedingly high this year in many areas of Missouri and insecticide application may be needed for control,” Bailey said.

Insecticides can kill most small grasshoppers easily. Apply insecticide on borders of fields and crop rows at this time to reduce numbers before grasshoppers move into crop fields.

CATCH THEM EARLY: Grasshoppers have been reported in high numbers this summer in Missouri. Spraying insecticide is suggested for control.

It is unusual for grasshoppers to be seen this early in the season in soybean fields, Bailey said. Early-season control becomes even more important if predictions for a dry end-of-season come true, he said.

Grasshoppers feed first on grasses and weeds in non-crop areas. When conditions are dry, grasshoppers travel from field borders to crop areas to find more green leaves, Bailey said. They can quickly strip leaves of crops.

Most severe damage occurs after several dry seasons. Cool, wet weather during egg hatch reduces numbers.

More than 100 species exist, but only a few are common in Missouri crops.

Brown, gray or green in color, they grow up to 1-¾ inches long. They have large hind legs for jumping and prominent heads with large eyes and complex mouthparts. Adults have two pairs of wings and can readily fly or jump when disturbed.

Grasshopper Hollow

Points of Interest:

  • Look out across the largest fen – a unique wetland – in the Ozarks.
  • See plants and animals that are ice-age relicts.
  • Enjoy the hum and flights of dragonflies and damselflies across the wetlands in summer.

Natural History:

Grasshopper Hollow contains the largest known fen complex in unglaciated North America. Fens are wetlands created when calcareous groundwater seeps out to the soil surface and are typically dominated by herbaceous plants kept open by both saturated soils and historically occasional wildfires. These fens are created by groundwater moving down through the Gasconade dolomite formation and hitting a resistant layer, likely sandstone, along which the water then runs horizontally and seeps out onto the lower slopes along the valley. Water that feeds these fens originates in the immediate 2,000 acre surface watershed but also from losing streams in the Logan Creek valley to the south, demonstrating the complexity of water movement in karst landscapes.

Fens at this site range from areas of shallow (up to 15 inches deep) muck soils dominated by sedges, ferns and wildflowers to deep (up to 40 inches deep) muck soils with pools of standing water and hummocks of sedges. An unusual prairie fen also occurs here and is dominated by a mix of prairie and fen plants growing in seasonally saturated soils. Eight plant and five animal species of conservation concern are found in these fens, including the Hine’s emerald dragonfly, a fen-restricted species of the midwest, that is listed as endangered by the U.S. Fish and Wildlife Service.

Many of Grasshopper Hollow’s rare species are considered “glacial relicts.” That is, they are species that were common in Missouri 10,000 years ago when glaciers covered the upper midwest. In the intervening thousands of years Missouri’s climate has gotten warmer and drier. The glacial relict species were able to persist in fens and along spring branches where cool groundwater provides appropriate habitat conditions. Other glacial relict species in Missouri persist on cool, moist north facing bluffs. At Grasshopper Hollow’s fens, glacial relicts include the four-toed salamander, wood frog, Riddell’s goldenrod, marsh blue violet, interior sedge, tussock sedge, sweet William phlox, and marsh bellflower. The combination of tallgrass prairie plants such as big bluestem and prairie cordgrass growing in association with characteristic fen plants such as orange coneflower and interior sedge is botanically interesting.

This wetland oasis is unusual in the otherwise dry and rocky Ozark landscape. Historically many Ozark valleys in the Black River basin supported fens. Because these areas were the best sites for settlers to crop and intensively graze livestock most fens have been destroyed or seriously degraded. Today The Nature Conservancy and the Mark Twain National Forest are using prescribed fire and watershed protection efforts to conserve the biological resource at Grasshopper Hollow.

Grasshopper Control in Missouri Forage Crops and Pastures

Wayne C. Bailey
Department of Entomology

Grasshoppers are relatively large insects, capable of doing considerable damage to many crops. In early summer, grasshoppers normally feed on grasses and weeds in non-crop areas, and later in the season, they move into fields. Grasshopper populations in Missouri are sporadic. In general, damage to crops is most severe in dry years.


Grasshoppers are brown, green or gray insects that may be as long as 1-3/4 inches. They have large hind legs for jumping and prominent heads with large eyes. Adult grasshoppers have two pairs of wings. The front pair is characteristically narrow and leathery, whereas the hind wings are thinner and more triangular. Although more than 100 species of grasshoppers occur in Missouri, four species are responsible for most crop damage. The large differential grasshopper and the redlegged grasshopper appear to be the most common pests, while the two-striped and migratory grasshoppers also occasionally cause problems.

Life cycle

Grasshoppers usually lay eggs in uncultivated soil in areas such as ditch banks, field margins and roadsides, as well as pastures, alfalfa and clover fields. Two-striped and differential grasshoppers lay their eggs near the roots of bunch grasses or alfalfa crowns covered with debris. These sites are usually along field edges or roadsides. Some species lay their eggs in specific bed areas.

Most kinds of grasshoppers lay eggs during late summer or early fall in pods of 20 to 100 eggs. One female grasshopper may deposit 8 to 25 egg pods. Generally, the eggs pass the winter, but in some instances, eggs may hatch and the emerging nymphs overwinter. Eggs hatch from May to June and, as the food source becomes scarce, the nymphs move to nearby fields. In drought-stressed fields, border vegetation is less abundant or dried out, causing nymphs to move quickly and in higher numbers into crops. Once in the field, grasshoppers may do serious damage to the forage crop or pasture. In Missouri, there is usually one generation per year, except for the migratory grasshopper, which has two.

Young nymphs are quite susceptible to weather and natural enemies. Cool, wet conditions during egg hatch reduce grasshopper numbers.

Typically, grasshopper damage consists of large, irregular holes extending from the margin to the center of the leaf. The growing tips of alfalfa and other plants may also be injured. Grasshoppers are capable of doing considerable damage in a very short time.

The biological control agent, Nosema locustae, is a naturally occurring microsporidian protozoan that is now being placed on various baits and marketed for grasshopper control under such names as NOLO Bait, Grasshopper Attack, Hopper Stopper and others. Although a promising biological, Nosema does not generally produce rapid control of grasshoppers, but rather is a slower, long-term method of grasshopper and cricket control. A major limitation of this control method is that grasshoppers must eat the Nosema-treated bait as second or third instar hoppers. This requires both early season scouting and treatment of grasshopper populations in border areas of the field.

The key to effective control of grasshoppers is early detection of the problem. Grasshopper nymphs are easier to kill, partly because of their small size and also because they are usually confined to the hatching area. Do not mow grass along field margins where high populations are found until grasshoppers are controlled. Mowing these feeding sites causes grasshoppers to move into adjacent crops.

In general, control is justified if 3 to 7 or more grasshoppers per square yard are present in alfalfa and clover fields or if 11 to 20 or more grasshoppers per square yard are present in pasture, range or non-crop lands. Keep in mind that the time of day, temperature and vegetation can influence the grasshopper’s activity and can affect the number you find.

Table 1 lists insecticides for controlling early season infestations of grasshopper nymphs when confined to non-crop land areas.

Table 1
Grasshopper control in non-cropland areas

Insecticide Product rate per acre Restrictions 1 Comments
Asana XL 2 2.9 to 5.8 ounces 4,5,6 Spray non-crop land adjacent tilled areas to control migrating hoppers. Treatment is warranted if 15 or more nymphs per square yard are present in non-crop areas.
Penncap-M 2 2 to 3 pints 3
Sevin XLR Plus 1 to 3 pints 2
Sevin 80S 2/3 to 1-7/8 pounds 2
Sevin 50W 1 to 3 pounds 2
1 Restrictions for grass pastures and non-cropland areas
  • Do not apply more than twice per season and allow at least 14 days between applications.
  • Preharvest or grazing interval is 0 days for aerial application and 14 days for ground application
  • Preharvest or grazing interval is 15 days after application.
  • Repeat application as necessary to maintain control, but do not exceed 0.5 pounds active ingredient per acre per year.
  • Do not feed treated crop to livestock.
  • Do not spray ditch banks or areas adjacent to water.
2 RU
Any insecticide preceded by RU (Restricted Use) means that all or some uses of this product have been restricted by the EPA.

Table 2 lists insecticides available for grasshopper control in alfalfa and clovers, and Table 3 lists insecticides for use on pastures or range grasses. Because of the short residual activity of insecticides registered for use on alfalfa and clovers, don’t expect more than temporary control of the present infestation. Reinfestation could occur in 10 to 14 days, at which time a second application may be required.

Table 2
Grasshopper control in alfalfa and clover

Insecticide Product rate per acre Restrictions 1 Comments
Cygon 400 1/2 to 1 pint 1,6,10 Control is warranted if 3 to 7 or more grasshoppers are present per square yard in alfalfa and clover fields.
Furadan 4F 2 1/4 to 1/2 pint 1,2,4,7
Guthion 3 2 1-1/3 to 2 pints 11,12,13,14
Lorsban 4E 1/2 to 1 pint 3,8
Penncap-M 2 2 to 3 pints 9
Sevin XLR Plus 1 to 3 pints 5
1 Restrictions for alfalfa and clover insectic >Do not apply more than once per cutting.
  • Do not apply more than twice per season and do not use more than 1 pint per acre in the second application.
  • Do not apply more than four times per year.
  • Apply only to fields planted to pure stands of alfalfa.
  • Preharvest or grazing interval is 7 days.
  • Preharvest or grazing interval is 10 days.
  • Preharvest or grazing interval is 7 days for 1/2 pint rate, 14 days for 1 pint rate and 28 days for 2 pint rate.
  • Preharvest or grazing interval is 7 days for 1/2 pint rate, 14 days for 1 pint rate and 21 days for rates above 1 pint per acre.
  • Preharvest or grazing interval is 15 days after application.
  • Do not apply if the crop or weeds in the crop are in bloom.
  • Apply twice per cutting at the 2/3 pint rate at intervals of 10 to 11 days.
  • Do not apply more than twice per cutting at the 2/3 pint rate.
  • Apply only once per cutting at rates above 2/3 pint.
  • Preharvest intervals are 14 days for 2/3 to 1 pint, 16 days for 1-1/3 pints, 21 days for rates above 1-1/3 pints.
  • 2 RU
    Any insectic >Table 3
    Grasshopper control in pasture and range grasses
    Insecticide Product rate per acre Restrictions 1 Comments
    Malathion 57 percent 1-1/2 to 2 pints 2, 5 Control is warranted if 15 or moregrasshoppers per square yard are present in grass pastures.
    Penncap-M 2 2 to 3 pints 4
    Sevin XLR Plus 1 to 4 pints 1, 3
    Sevin 80S 2/3 to 1-7/8 pounds 1, 3
    Sevin 50W 1 to 3 pounds 1, 3
    1 Restrictions for pastures and range grasses:
    • Do not apply more than twice per season and allow at least 14 days between applications.
    • May be applied day of harvest.
    • Preharvest or grazing interval is 0 days for aerial application and 14 days for ground application.
    • Preharvest or grazing interval is 15 days after application.
    • Do not apply if the crop or weeds in the crop are in bloom.
    2 RU
    Any insecticide preceded by RU (Restricted Use) means that all or some uses of this product have been restricted by the EPA.

    How to spray

    For effective control of any insect pest, calibrate the sprayer to apply sufficient gallonage at a speed that will give good coverage. Gallonage varies with the height and density of the foliage. Most situations require at least 12 gallons of spray per acre for effective coverage.

    Don’t spray when wind velocities exceed 10 to 12 miles per hour and avoid drift into nearby gardens and fields. For best control, especially with malathion, apply only when temperatures are 60 degrees Fahrenheit or above and are expected to remain this warm for one or two days after application.


    Always handle insecticides with caution, regardless of whether or not they are restricted-use compounds. Read, understand and follow the directions on the label concerning use and safety measures. Wear the protective clothing and devices suggested on the label.

    Avoid breathing vapors or dust, and direct contact with skin. If the insecticide concentrate contacts or contaminates the skin, immediately wash the affected area with soap and plenty of water, then change and discard clothing.

    Store insecticides in their original container with legible labels securely attached. The storage area should be dry and locked at all times when not actually in use. To prevent contamination of surrounding crops, water or wildlife habitat, promptly and properly dispose of empty containers as directed on the label.

    Differential Grasshopper

    Melanoplus differentialis (Thomas)

    • M. differentialis Identification
    • Next Species in Subfamily: Melanoplus femurrubrum
    • Previous Species in Subfamily: Melanoplus devastator
    • List of Species Fact Sheets
    • Field Guide Contents

    Link directly to photos of adults, nymphs, or eggs.

    Distribution and Habitat

    The differential grasshopper, Melanoplus differentialis (Thomas), ranges widely in North America. Originally restricted to tall herbaceous vegetation growing in wet meadows, swales, and creek bottom lands, the species spread into the weedy vegetation of crop borders, roadsides, and reversions brought about by settlement and agricultural development. In the United States large populations develop in extensive areas of cropland located between the Rocky Mountains and the Mississippi River. Populations east and west of these landmarks are spotty and discontinuous.

    Economic Importance

    Food Habits

    Migratory Habits

    Adults display strong powers of flight. In search for green food, they may move upwind in short, low flights of 10 to 100 yards toward green corn. These flights begin around 9 a.m. and reach a peak when temperatures rise to 81°F.

    Flight also provides escape from extreme heat of temperatures above 86°F. Grasshoppers rise and mill about in calm air or fly with the wind. They have been seen by airplane pilots as high as 1,400 feet above the ground, but most have been seen below 600 feet. In 1939 the differential grasshopper migrated northward by successive short flights from along the Missouri River in southeastern South Dakota to as far north as Pierre, South Dakota, a distance of 130 miles. In North Dakota one differential grasshopper of a marked group was recovered 20 miles from the point of release two days after its liberation. During outbreaks of this species adults have longer wings and slimmer bodies.


    The adult male (Fig. 7) is identifiable by the shape of the cercus (Fig. 9) and both male and female by the black chevrons on the hind femur. A melanistic female is pictured in Figure 8. The majority of females are yellow with black markings like the male shown in Figure 7.

    The nymphs (Fig. 1-6) are identifiable by their spots, stripes, and color patterns:

    (1) Compound eye brown with light tan spots; lacking transverse dark band.

    (2) Front of head green, yellow, or tan often with dark spots and a few larger markings.

    (3) Pronotum with pale yellow, horizontal stripe at top of lateral lobe; brown band at edge of pronotal disk; narrow, median pale yellow stripe on pronotum, mesonotum, metanotum, and continuing on to abdomen various distances.

    (4) Gena with short, pale yellow band below compound eye and continuous with pale yellow stripe of lateral lobe. Band faint or lacking in fifth and sixth instars.

    (5) Black stripe of hind femur occupying center of medial area in first to fourth instars; black chevrons beginning to be evident in fifth and sixth instars. Black stripe in first instar often interrupted by pale band.

    (6) Hind tibia light green or light gray to gray.

    (7) General color pale green, pale yellow, or tan; many fuscous markings.

    Nymphal Development

    Adults and Reproduction

    Egg pods of the differential grasshopper are curved, one and one-half inches long and one-quarter inch in diameter. They are fragile and easily broken in sifting them from the soil. The eggs are olive and 4.4 to 5.1 mm long. In separate laboratory experiments, females fed a single plant diet of soybeans averaged 305 eggs each while those fed common sunflower averaged 591 eggs each. The maximum number of eggs deposited by a single female fed soybean was 645 and the maximum number of pods was six. The number of eggs laid by females in nature is unknown. There is one generation annually.

    Population Ecology

    The high biotic potential of the differential grasshopper is evident in the records of an outbreak that occurred more than 50 years ago in Missouri. In 1934 the differential grasshopper was present in noneconomic numbers. In 1935 this species became more numerous, damaging fall wheat and alfalfa. The warm, dry summer and fall of 1935 provided favorable conditions for egg production. The next year, 1936, spring rains and warm temperatures allowed a successful hatch and nymphal development that precipitated the worst outbreak of grasshoppers in Missouri since the years of the Rocky Mountain locust. Favorable weather continued and allowed the differential grasshopper to stay at outbreak numbers in 1937; the fall egg survey that year showed the greatest density of eggs ever. In 1937 the eggs hatched but this period was followed by rains and cool weather. The emerged nymphs died ending the outbreak.

    Daily Activity

    Like the nymphs the adults rest high on plants at night and descend only when temperatures are 68°F or above and the sun rises and strikes both them and the ground. Upon descending they begin to feed. Feeding slackens at 86°F and ceases at air temperatures above 90°F and soil surface temperatures above 112°F. At these high temperatures, air 86° to 90°F, adults seek shade or rise in flight. Table 1 summarizes information on the influence of temperature upon activities of nymphs and adults.

    Selected References

    Kaufmann, T. 1968. A laboratory study of feeding habits of Melanoplus differentialis in Maryland (Orthoptera: Acrididae). Ann. Entomol. Soc. Am. 61: 173-180.

    Lewis, A. C. 1984. Plant quality and grasshopper feeding: effects of sunflower condition on preference and performance in Melanoplus differentialis . Ecology 65: 836-843.

    Munro, J. A. and S. Saugstad. 1938. Grasshopper migration in North Dakota. North Dakota Agric. Exp. Stn. Bimonthly Bull. 1(1): 4-5.

    Parker, J. R. and R. L. Shotwell. 1932. Devastation of a large area by the differential and the two-striped grasshoppers. J. Econ. Entomol. 25: 174-196.

    Sanderson, M. W. 1939. Crop replacement in relation to grasshopper abundance. J. Econ. Entomol. 32: 484-486.

    Slifer, E. H. 1932. Insect development IV. External morphology of grasshopper embryos of known age and with a known temperature history. J. Morphol. 53: 1-21.

    Swenk, M. H. and C. H. Bratt. 1941. The relation of temperature to the embryonic and nymphal development of the differential grasshopper Melanoplus differentialis Thomas. Nebraska Agric. Exp. Stn. Res. Bull. 122.

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