Control in Gardens and Small Acreages Fact Sheet No. 5.536 Series|Home and Garden by W.S. Cranshaw and R. Hammon* can be the most noticeable late-spring, varying with soil temperatures. Quick Facts and damaging to yards and fields. At egg hatch the tiny first stage nymphs move They also are among those most difficult to to the surface and seek tender foliage on • Grasshoppers are the control, since they are highly mobile. For which to feed. The first few days are critical most difficult insect to many reasons, grasshopper populations to survival. Adverse weather or absence control because they are fluctuate greatly from year to year, and of suitable foods can cause high mortality. highly mobile. may cause serious damage during periodic Surviving grasshoppers continue to develop outbreaks. Problems tend to increase over the next several weeks, usually molting • All grasshoppers lay their beginning in early summer and can persist through five or six stages, before ultimately eggs in soil. until hard frosts. reaching the adult form. • There are over 100 of Over 100 species of grasshoppers occur Adult grasshoppers may live for months, grasshoppers in Colorado. in Colorado and their food habits vary. Some interspersing feeding with mating and egg primarily feed on grasses or sedges, while laying. Species that winter in the egg stage • During periods when local others prefer broadleaved plants. Other die out in late summer and early fall. A few outbreaks are developing, grasshoppers restrict their feeding to plants of species, perhaps most conspicuously the control usually involves using no great economic value and a few even feed speckledwinged grasshopper, spend winter sprays or baits. primarily on weed species (e.g., snakeweed). as a nymph, remain active during warm However, others will readily feed on garden periods, and may develop to the adult form and landscape plants (Table 1). by late winter. Among vegetable crops certain plants are favored, such as lettuce, carrots, beans, sweet corn, and onions. Squash, peas, and tomatoes (leaves, not fruit) are among the plants that tend to be avoided. Grasshoppers less commonly feed on leaves of trees and shrubs. However, during outbreak years even these may be damaged. Furthermore, grasshoppers may incidentally damage shelterbelt plantings when they rest on twigs and gnaw on bark, sometimes causing small branches to die back.

Figure 1: Differential grasshopper. Grasshopper Life History All grasshoppers lay their eggs in soil, in the form of tight clustered pods. Relatively dry soils, undisturbed by tillage or irrigations, are preferred. Egg laying may be concentrated at certain sites with favorable soil texture, slope, and orientation, producing ‘egg beds.’ The egg stage is the overwintering stage of most, but not all, grasshoppers. For the © Colorado State University majority of species the eggs hatch in mid- to Extension. 4/96. Revised 1/13. www.ext.colostate.edu *W.S. Cranshaw, Colorado State University Extension Figure 2: Migratory grasshopper. entomologist and professor, bioagricultural sciences and pest management; and R. Hammon, Extension entomology and agronomy agent, Mesa County. 1/2013 Table 1: Primary grasshoppers that damage gardens and small acreage pasture areas in Colorado. Common Scientific Name Name Comments Differential Melanoplus Often one of the first grasshoppers found moving into grasshopper differentialis gardens and one of the largest in the genus Melanoplus. Migratory Melanoplus Often the most damaging species to croplands. Any early grasshopper sanguinipes hatching species and capable of long migration flight. Twostriped Melanoplus Often the most common species damaging gardens, it grasshopper bivittatus migrates from empty lots, roadsides, and other undisturbed sites. It often hatches in late spring, a few weeks later than many grasshoppers. Redlegged Melanoplus A widely distributed grasshopper that feeds on many garden grasshopper femurrubrum plants. It tends to be most abundant in moist sites and is one of the later hatching species. Clearwinged Camnula The primary species present in recent outbreaks reported in grasshopper pellucida areas of the West Slope and around Steamboat Springs. An early hatching grasshopper that restricts feeding to grasses. Figure 5: Clearwinged grasshopper.

Grasshopper Control cycles along with their grasshopper hosts. Treatments should be directed at the Natural Controls Adult robber flies are common predators young grasshoppers and nearby vegetation of grasshoppers during summer and present in these breeding sites. At lower The most important factors are weather other flies develop as internal parasites altitudes, this often occurs in May; related, particularly around the time of of grasshoppers. Many birds, notably early June may be the optimal time for egg hatch. For example, cold, wet weather horned larks and kestrals, feed heavily grasshoppers at higher elevations. Sprays is very destructive to newly hatched on grasshoppers. Grasshoppers are also of insecticides are most effective at this grasshoppers. However, very dry winter frequently eaten by coyotes. time and several insecticides are effective and spring conditions also can be harmful Grasshoppers are also subject to some (Table 2). Insecticide options are greater to survival since required tender new plant unusual diseases. A fungus (Entomophthora for larger acreages and unit costs are less growth is not available. grylli) infects grasshoppers causing them to expensive. The addition of canola oil to Some insects commonly feed on move upwards and cling to plants shortly insecticide sprays can improve control by grasshoppers. Many species of blister before they kill the insect host. Stiff, dead making treated foliage more attractive to beetles (see fact sheet 5.524, Blister Beetles grasshoppers found stuck to a grass stem feeding grasshoppers. in Forage Crops) develop on grasshopper or twig indicate infection with this disease. Alternately, baits containing carbaryl egg pods and blister beetle abundance A very large nematode (Mermis nigriscens) (Sevin) can be broadcast. Bait formulations also sometimes develops in grasshoppers. are made by mixing the insecticide Both the fungus disease and nematode with bran or some other carrier and kill parasite are favored by wet weather. grasshoppers that feed on the bait. These treatments limit application effects on other Managing Grasshoppers with Baits insects present in the treated area. However, and Sprays availability of Sevin baits is frequently During periods when a local outbreak limited, or prohibitively priced for use develops, control usually involves using on large areas. Baits must be reapplied sprays or baits. To be successful these after rain. need to be applied to developing stages Insecticide treatments do not need of grasshoppers and concentrated at sites to completely cover the area since where egg laying occurs. Ability to control grasshoppers are mobile. Insecticides applied as bands covering 50 percent of the Figure 3: Twostriped grasshopper. grasshoppers declines as grasshoppers develop and migrate. Surveys of grasshoppers can be very For identification of many useful in anticipating problems and treating appropriately. Numbers of grasshoppers grasshoppers found in Colorado and present in late summer and early fall images of the various developmental can be a good indicator of problems the stages, the University of Wyoming subsequent year. Follow-up surveys the has prepared a series of fact sheets, following spring to detect young nymphs accessible through the USDA-ARS can determine when eggs have hatched. website: www.sidney.ars.usda.gov/ Area-wide surveys may locate egg grasshopper/ID_Tools/F_Sheets/ beds and other sites where early season index.htm. activity originates. Figure 4: Redlegged grasshopper. Table 2: Insecticides used to control grasshoppers. Other Controls Common Trade Name Name(s) Labeled Uses, Comments If insecticides are not used, some carbaryl Sevin Most formulations allow use on a wide variety of fruits and protection of a garden may be vegetables (1-14 day preharvest interval). Available for use as sprays, dust and in baits. possible by watering grasshopper breeding areas to promote plant acephate Orthene Has systemic activity in plants and may persist longer than most other insecticides. Uses are limited to non-edible crops. growth. This may retard migrations of grasshoppers to areas of more permethrin Many trade Widely available for garden use and most formulations allow use names. on a wide variety of fruits and vegetables. Fairly short persistence desirable plants. Mowing or other of effect for grasshopper control. activities that deny food plants in diflubenzuron Dimilin Growth regulator that affects chitin formation as grasshopper breeding sites should be avoided. nymphs molt. Effective only on immature insects but has long residual activity. Restricted Use insecticide. Most use will be by Susceptible plants may be protected licensed pesticide applicators on pastures. by screening or cheesecloth barriers. However, grasshoppers can chew Nosema NOLO Bait, A biological control that produces infection from a protozoan. It is locustae Semaspore relatively slow acting and only effective against young grasshoppers. through most fabrics. Use allowed in Certified Organic crop production. Repellents do not appear to be effective. Some materials used as Nosema locustae Baits repellents, such as vegetable oils Baits containing the protozoan Nosema and garlic-based preparations, may locustae is a biological control option that instead increase grasshopper feeding may be considered for treating grasshopper on plants. breeding sites. This is sold under the trade names NOLO Bait or Semaspore and Poultry may feed heavily on can produce infection of many species grasshoppers. Turkeys, guinea hens, of grasshoppers. Because it is selective in and chickens have all been used to effects, only affecting grasshoppers, its use help control grasshoppers. However, is sometimes considered desirable. garden areas may need to be fenced There are some limitations toNosema Figure 6: Grasshopper egg bed. since scratching by chickens can be locustae baits. Only young grasshoppers harmful to young plants. are susceptible, and it can not be used effectively after adult migrations have occurred. It is also fairly slow acting and area, or even less, have proved very effective does not equally infect all grasshopper for control of grasshoppers in rangelands. species. Often it is most effectively used Backpack sprayers and application in a long-term grasshopper management equipment modified for use on ATVs can program, in combination with be used in larger acreages. A review of this other controls. method, known as Reduced Area Acreage Nosema locustae baits are also Treatments (RAATS) has been prepared by perishable. They are best kept refrigerated the University of Wyoming at: www.sdvc. before use. Expiration dates are usually uwyo.edu/grasshopper/atvraats.htm printed on packages and should be checked. Figure 7: Specklewinged grasshopper. Where grasshoppers develop over large areas and impact several properties, coordinated area-wide control is very Some Interesting and useful. As this requires some additional Unusual Grasshoppers preparations in planning, early surveys Among the 100-odd species of are even more important. Grasshopper Colorado grasshoppers are some that may control often is much more successful as a attract attention because of unusual size, community effort. coloration or habit (Table 2). None of these Once grasshoppers have reached the are damaging to gardens and croplands adult stage and migrations occur, some because they do not develop outbreak insecticides may be applied directly to populations or limit their feeding to plants plants. Such applications have only short that are not economically important. Figure 8: A mating pair of plains lubber grasshopper. effectiveness and damage can occur Speckledwinged grasshopper (Arphia before individual grasshoppers are killed. conspersa) - This is the grasshopper most Furthermore, the choice of insecticides commonly observed during warm days is more limited since few allow direct of winter and early spring. Eggs of the application to garden fruit and vegetables. speckledwinged grasshopper hatch in and brown. The plains lubber will feed on many plants, but is most commonly associated with patches of sunflowers. Carolina grasshopper (Dissosteira carolina) – A grasshopper commonly disturbed to flight when walking along open areas of bare earth. The hindwings are dark with a light band along the edge and in when flying may hover and produce a faint audible noise. Overall color ranges are Figure 9: Carolina grasshopper. light greyish yellow to reddish brown and Figure 11: Mormon cricket female. (Photo they often blend well with soil background. courtesy John Capinera.) mid-late summer and they spend winter as They feed on a variety of plants but rarely nymphs and, later, adults. The adults have become abundant enough at a site to cause yellow. It is a grass feeder found in dry, colored hindwings, often with a yellow any serious damage. prairie areas. or reddish spot and in flight they make a Barber pole grasshopper/Pictured Spotted bird grasshopper/Lined bird crackling noise. They limit their feeding to grasshopper (Dactylotum bicolor) – This grasshopper ( alutacea) – A grasses and sedges. is the most colorful grasshopper found in very long grasshopper (ca. 2-inch long) and Plains lubber/Homesteader the state with markings of reddish orange, strong flier. The lined bird,S. a. shoshone, (Brachystola magna) – This is the largest black and yellow. It occurs in areas of the is found along riverways and moist ravines grasshopper found in the region, an may eastern plains and adults are present in late where it feeds on various shrubs. The Great exceed 3 to 4 grams in weight. It has stubby summer. They feed on broadleaf plants, but Plains/sandhills subspecies, S. a. lineata, wings and it is flightless, but can be often usually only those of low forage value and it is found in dry, shrubby areas with large seen in midsummer slowly hopping across is not considered a pest species. weeds. Adults are present in late summer rural roads in eastern Colorado. The body Greenstreaked grasshopper/ and early fall but are never very abundant. is colorful, with a mixture of green, pink Snakeweed grasshopper (Hesperotettix Mormon cricket (Anabrus simplex) viridis) – A bright green, colorful – This large insect is neither a cricket grasshopper found throughout much nor a true grasshopper, but a longhorned of the state but most common on the grasshopper (Tettigoniidae family), related eastern plains. It feeds on a limited to a katydid. It lives on the open sagebrush/ number of plants, including many that grassland rangelands of the Colorado are considered rangeland weeds (e.g., Plateau and Great Basin at elevations snakeweed, ragweed). between 6,500 and 11,000 ft. It attracts Red shanks (Xanthippus corallipes) attention because of periodic massive – A large grasshopper active earlier in the migrations of millions of individuals year than most species. The body color is that may devour significant amounts irregularly splotched and banded, allowing of vegetation. Mormon crickets prefer it to camouflage on bare soil. However, broadleaf plants, but will also eat range the hindwings are bright pink, orange or grasses and many crop plants.

Figure 10: Barber pole grasshopper, late stage nymph.

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