Pasture and Alfalfa Insects. Dr. Wayne Bailey Extension / Research Entomologist Field and Forage Crops University of Missouri

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1 Pasture and Alfalfa Insects Dr. Wayne Bailey Extension / Research Entomologist Field and Forage Crops University of Missouri

2 How Many Kinds of Insects Recorded? 200 thousand 2 million 20 million 200 million 2 billion

3 How Many Kinds of Insects Recorded? 200 thousand 2 million 20 million 200 million 2 billion 10 billion estimated

4 Why is accurate insect identification so important? Vast majority of insects are not pests. Alfalfa: species annually; <1% pest Not all insect species are equally susceptible to different insecticides, even if related or similar in appearance. Some insects develop resistance to some insecticides. The behavior of related species can differ a great deal, & this can affect control measures.

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7 4 stages Egg Larvae Pupa Adult Complete Metamorphosis

8 Gradual Metamorphosis Egg Nymph Adult

9 Why are insect pest species so successful? Small size Most have high reproductive rates Many are highly mobile (flight) Highly adaptive genetically and/or behaviorally Metamorphosis (habitat flexibility) Many are exotic, & adequate biocontrol organisms are usually unavailable to suppress pest populations.

10 What is IPM Integrated Pest Management is an ecologically-based, comprehensive approach of controlling diseases, insects and weed pests through the intelligent selection and integration of pest control strategies which are economically viable, environmentally sound, & sociological acceptable.

11 Economic Injury Level The pest density at which damage can no longer be tolerated without experiencing economic loss.

12 Economic Threshold The pest density at which control measures should be applied to prevent an increasing pest population from reaching the economic injury level.

13 Potato Leafhoppers (common pest of Alfalfa) EIL ET GEP Time

14 Forage Insect Pests True Armyworm tall fescue and other grass pastures, often local, regional, or even statewide infestations.

15 True Armyworm Mythimna unipuncta (Haworth) -Native insect; night flying moth (Noctuidae) -Feeds mainly on grasses -2 to 3 generations annually in MO -1 st generation often attacks field and forage crops -Larvae usually feed from ground upward as early instars avoid light -Most easily scouted during dawn, dusk, or at night -Causes problems somewhere in MO almost every year

16 True Armyworm Pseudaleta unipuncta (Haworth) Pest of many different crops including: 1. Wheat, oats, barley 2. Tall Fescue 3. Grass Pastures (especially rye) 4. Field Corn

17 Forage Insect Pests Armyworm in Grass Pastures Pest difficult to detect as larvae fed low on plants before feeding on upper foliage. Forage yields greatly reduce, some rescued with insecticides (Sevin, Mustang Max, Warrior II)

18 Easy Identification of Armyworm (True) Larvae Armyworm larva Note dark triangular markings on tips of four pairs of abdominal prolegs

19 True Armyworm Identifying characteristics note: 1. Tan colored moth with 1 to 1 ½ wing span with a white spot present near center of each forewing Identifying characteristics note: 1. salmon colored line running down each side of larva 2. dark triangles present on tips of four pairs of abdominal prolegs

20 True Armyworm Larvae

21 True Armyworm Damage Damage to Wheat & Tall fescue Damage to Field Corn

22 True Armyworm Damage Economic Threshold in Tall Fescue: Treatment in Tall Fescue is justified when an average of four or more non-parasitized, half-grown or larger worms per square foot are present. Scouting is best conducted at dawn, dusk or at night as small larvae often avoid light and remain close to ground during day and move upward to feed at night

23 True Armyworm BioControlAgents Wasp Parasite - internal pupation Fungal Pathogen Wasp Parasite external pupation

24 True Armyworm Armyworm in Wheat and Grass Pastures Economic infestations of this pest depends on overwintering moths and spring moth flight from South, weather conditions, and the absence of beneficial insects early season Does not attack legume plants.

25 Fall Armyworm Major outbreak in seedling alfalfa and grass pastures during fall 2012 Pest of many field crops throughout growing seasons in most years. Foliage feeder capable of building to very high larval and adult numbers. Light color phase Infests: Alfalfa Corn Grasses Legumes Soybean dark color phase

26 Japanese Beetle Adults

27 Japanese Beetle Popillia japonica Newman First reported in Missouri in 1932, but first reported as economic pest in 1936 MU Extension Pest Bulletin Initially found in St. Louis area with damage reported on 12 tree and flower species, especially roses and linden trees. Stayed in St. Louis area until 1990 s when beetles began moving westward. Currently found in most Missouri counties.

28 Japanese Beetle Damage to Corn Silks

29 Schematic of Japanese Beetle Life Stages

30 Threshold for Soybean: Insecticide treatment should be considered when defoliation reaches 30% before bloom and 20% before bloom and pod fill. Flowering soybean fields are especially attractive to adult Japanese Beetles.

31 Japanese Beetle Host Plants Adults beetles eat over 440 different plant species. Common preferred host include: Asparagus, beans, birch, blackberries, blackberry bushes, blueberries, corn, crape myrtle, crab apples, grapevines, grapes, hibiscus, honeysuckle, linden trees, maples, morning glory, okra, peaches, plums, privet, raspberry leaves, rose bushes, strawberries, soybean foliage, sunflowers, sycamore, tomatoes, willow, wisteria, and zinnia pasture plants?

32 Bronze Cutworm

33 Bronze Cutworm Feeds mainly on bermuda grass in late spring, early summer Often controlled by biological pathogens, but usually not before much vegetation has been consumed by larvae.

34 Bronze Cutworm

35 Bronze Cutworm

36 Bronze Cutworm

37 Alfalfa History Origin in Iran Initially spread through middle east by Roman Legions as forage source for animals. In U.S million acres of alfalfa annually produce about 79 million tons of hay with a value of $ 8.1 billion. About 450,000 acres of pure-stand alfalfa are grown in Missouri annually.

38 Alfalfa Insects How many insect species can be found in a typical alfalfa field throughout a growing season? Alfalfa is considered to be a very high energy, ecologically rich environment which typically supports 500 to 1000 species annually.

39 Alfalfa Weevil Adult

40 Alfalfa Weevil Biology Life history: Overwinters as adults in alfalfa fields, 1 in-season generation per year. Damage: Usually attack first cutting. Larvae feed for 3-4 weeks & move downward from the terminal to the older leaves. Damaged leaves have a skeletonized appearance & fields a frosted one. ET (MO): 1 larvae/stem & 30% terminal damaged. Control: Early cutting, conserve beneficials, & time insecticide sprays for non-blooming alfalfa.

41 Alfalfa Weevil Biology

42 Alfalfa Weevil Biology Alfalfa weevil adult: note characteristic weevil snout

43 Alfalfa Weevil Biology

44 Alfalfa Weevil Biology

45 Alfalfa Weevil Damage

46 Alfalfa Weevil Damage

47 Alfalfa Weevil Damage Treated Untreated

48 Alfalfa Weevil Biology

49 Alfalfa Weevil Scouting

50 Alfalfa Weevil Management Options Insecticide Application

51 Alfalfa Weevil Management Options Early Harvest

52 Alfalfa Weevil Management Options Grazing

53 Alfalfa Weevil Management Options Biological Control

54 Alfalfa Weevil Parasite pupae Pupal cases of parasitic wasps

55 Alfalfa Weevil Management Options Mixed Stands

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57 Potato Leafhopper Biology Potato Leafhopper Adult & Nymph

58 Potato Leafhopper Biology Life history: Migratory (March and April), build to damaging levels in June/July; life days, many generations per year. Damage: Both adults & nymphs use their piercing-sucking mouthparts to extract plant juices. This damage causes yellowing or hopperburn of leaves & stunts plant growth. ET (MO): 0.2 to 2 leafhoppers / sweep (dependent on plant height) Control: Early cutting & properly timing insecticide sprays.

59 Potato Leafhopper Biology - Migration

60 Potato Leafhopper Damage: hopperburn Yellowing caused by PLH

61 Potato Leafhopper Scouting

62 Potato Leafhopper Economic Thresholds Thresholds based on plant height

63 Potato Leafhopper Management Options Grazing

64 Potato Leafhopper Management Options Insecticide Application

65 Potato Leafhopper Management Options Early Harvest

66 Potato Leafhopper Management Options Mixed Stands

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68 Potato Leafhopper Management Options Glandular Haired Varieties

69 Changes in thresholds Economic Threshold for Potato Leafhopper - Alfalfa Stem Length Inches Non-resistant Average # PLH / Sweep Resistant Average # PLH / Sweep < * * * * * For 2 year and older alfalfa fields

70 Potato Leafhopper Economic Thresholds Traditional Alfalfa Varieties: Alfalfa height Ave # PLH / sweep < PLH Resistant (glandular haired) Varieties: Multiply traditional thresholds by 3 for new PLH resistant varieties

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73 Blister Beetles

74 Blister Beetle Biology Life history: Overwinters as larvae in soil, many generations per year. App. 7 species of blister beetles in MO, striped most common and contains highest amount of cantharidin. Damage: Rarely causes yield reduction, but it produces a toxin (cantharidin) that s potentially lethal to horses. Control: Management of blister beetles involves: Good weed control, harvest before alfalfa blooms (blooms very attractive), feed 1st cutting to horses, avoid using hay conditioners, & apply insecticides (ex. Sevin) when blister beetles are present.

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76 Blister Beetle - Gregarious behavior

77 Blister Beetles Management Options Management Strategies for reducing risk of Blister Beetle poisoning of horses Use only first cutting alfalfa for horses Cut alfalfa at 1/10 th bloom Eliminate weeds from alfalfa stand Scout fields for BB and treat if necessary Check alfalfa hay for presence of BB Do not use hay conditions which crush hay

78 Scarabs Beetles Family Scarabaeidae (Order Coleoptera) dung beetles (dung-eating) chafer beetles (plant-eating) Most scarabs: are stoutly-built insects with remarkable strength, often with broad, powerful legs bearing strong spines as an adaptation for burrowing in the soil Egyptians believed that the scarab beetle came into being spontaneously from balls of dung and they associated this with their religious ideology of self-creation and resurrection. Thus, the scarab beetle was worshipped under the name Khepri (meaning 'he who has come into being' or 'he who came forth from the earth'). Dung Beetle presentation adapted from Kent fothergill and Dr. Kelly Tindall, formerly from the MU Delta Research Center

79 Dung Beetle Types Based on Behavior Cross section through dung pat depicting three nesting types: Tunnelers I-A. Phanaeus vindex tunnel with single, soil-coated brood ball in single chamber; B. Onthophagus species tunnel with multiple brood masses; C. Copris minutus multiple brood balls; D. beetle excavating new tunnel (note subsurface soil is pushed through the dung pat crust) Dwellers II-A. Aphodius pseudolividus eggs are laid singly or in groups inside dung pat; B. Aphodius erraticus bury dung under pat with eggs laid beside brood masses. Rollers III-A. Canthon pilularius adult carving out dung into a ball; B. ball rolled a distance away from pat and buried shallowly.

80 Hundreds of Dung Beetle Species in the US: Dwellers Buriers Rollers jorycaron.com

81 Beetles live inside the cow pie Dwellers Most frequent behavior in the Group Aphodiinae Aphodiinae most commonly recovered

82 Buriers Multiple strategies, similar in nature Adult Egg Pupa Larva

83 Adults arrive at a dung source Excavate a portion of the dung The portion is formed into a ball The ball is rolled distance away from the pat by one or both parents Egg is laid in ball brood ball Larvae develop within the brood ball Rollers

84 Dung Beetles working Dung Pat

85 Dung Beetles Cow manure feeding dung beetles introduced into the U.S. Most notable = Onthophagus gazella African species imported from Australia 1970 Texas in 1972 for pasture improvement Another notable = Onthophagus taurus 1971 accidentally introduced into Florida Later intentionally released in several areas including California, Texas and New Jersey Both are efficient in dung removal and have spread throughout the eastern U.S. Additional species have been released and/or colonized in the U.S.

86 Dung Beetle Male Dominance

87 Commom Dung Beetle Species Associated With Pastures Phanaeus vindex Phanaeus vindex Phanaeus vindex Size: 3/8-7/8 ( ) Size: 3/8-7/8 ( ) Size: 3/8-7/8 ( ) Photographs by Matt Bertone Onthophagus taurus Size: 1/4-3/8 ( ) Onthophagus taurus Onthophagus taurus Size: 1/4-3/8 ( ) Size: 1/4-3/8 ( ) Onthophagus gazella Size: 3/8-1/2 ( ) Onthophagus gazella Size: 3/8 1/2 ( )

88 Aphodius distinctus Size: 1/8-3/16 Commom Dung Beetle Species Associated With Pastures Aphodius erraticus Size: 1/4-3/8 Aphodius fimetarius Size: 1/4-3/8 Aphodius pseudolividus Size: 1/8-3/16 Geotrupes blackburnii Onthophagus hecate Size: 3/8-3/4 Onthophagus hecate Onthophagus hecate Size: 1/4-3/8 ( ) Size: 1/4-3/8 ( ) Size: 1/4-3/8 ( ) Onthopagus pennsylvanicus Size: 1/8-1/4 Canthon pilularius Size: 1/2-5/8 Dichotomius carolinus Size: 3/4 1¼ Photographs by Matt Bertone

89 Attracted to the smell Some are specialists Locating the Dung Manure of a specific animal Fly up to 10 miles in for right dung Attack pats within seconds after dropping Some near the tails in anticipation

90 Size = 0.9 ft 2 1 cow = 10 / day jorycaron.com

91 Avoidance of Areas near Cow Pats Cattle don t like to eat forage near pats Research has shown that the forage is palatable, but avoided because of the dung pile 5-10% per acre per year unavailable Quick removal of manure by dung beetles = enhanced grazing efficiency

92 Rate of Dung Removal Number of individuals Species composition Fecundity Adult longevity Soil type Climatic conditions Time of year Mean weight of dung per nest (g) Adapted from Lindquist (1933) Type of food an animal ate

93 Recovery of Nitrogen Not Buried Buried 37% Up to 80% volatilization of N if not broken down quickly Dung = 1-3% nitrogen by weight 5 pairs of O. nuchicornis Return of ~125 lb N/A Larger, more vigorous beetles = 80-95% of nitrogen Ideal populations and mix of beetles = complete removal - 2 hrs Adapted from: Macqueen and Beirne (1975) Photo credit:

94 Improved Plant Growth Japanese Millet Plant Biomass (g) Adapted from: Bornemissza (1970) Fertilization rate of 135 lbs of the same N and P combination per acre.

95 Improved Plant Growth Bermudagrass Dry Matter (kg/ha) Adapted from: Fincher et al. 1981

96 More Benefits of Dung Beetles Buriers -only 40 50% of the brood ball used before pupating Makes manure nutrients available to secondary decomposers Tunneling increases soil aeration and its capacity to absorb and hold water Processing enhances soil nutrient cycling Decreases ammonia volatilization and nutrient runoff Reducing non-point sources of organic pollution

97 Other Dung Inhabitants Face flies Horn flies (60 80 per pat) Gastrointestinal parasites eggs (tapeworms, liver flukes etc. ) jorycaron.com

98 Dung Beetles: 95% Reduction in horn flies (competition for resources) Dung = parasitic egg incubator remove dung, break parasite life cycle jorycaron.com

99 Problems Using Dung Beetles Fertilizer + increased forage yields = more cattle per area of land Too much dung, not enough dung beetles not able to keep up with increased livestock production Pesticides applications on pastures and wormers reduces dung beetle populations Ivermectin injection - reduced survival for 1-2 weeks Ivermectinpour-on -reduced survival for 1-3 weeks Ivermectinas a bolus -effects lasting up to 20 weeks

100 Summary Increased pasture yields from incorporating organic matter into the soil, reduced compaction, and increased aeration, and water holding capacity Reduction of pest populations that breed in dung Reduce diseases (remove contaminated dung) Return nutrients to soil that would otherwise be tied up in dung and unavailable to pasture grasses Increased effective grazing areas covered by dung Prevent pasture surface pollution Reduce nitrogen loss in dung

101 Dung Beetle Olympians 1. Increase the rate of manure pat decomposition 2. recycle soil nutrients 3. Increase soil health and quality 4. Reduce problems with flies and animal parasites 5000 species of dung beetles described pull 1,141x body weight=average person pulling six double-decker buses full of people replant forests bury 250 times its own weight in manure in one night live up to 3 years pairs will dance on the dung after the ball is formed

102 Conserving Dung Beetles 1. Use Cydectin or Moxidectin if possible; easy on beetle larvae 2. Worm cattle late fall or winter when dung beetles inactive 3. Avoid using mineral/wormer combinations when beetles active

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