GRASSHOPPER MANAGEMENT IN NEW MEXICO Train-the-Trainers Workshop presented by Alexandre Latchininsky and Scott Schell, UW Extension Entomologists Sponsored by: USDA-APHIS-PPQ

Disclaimer Trade or brand names used in this presentation are used only for the purpose of educational information. Trade or brand names used in this presentation are used only for the purpose of educational information. No product endorsement is implied. No product endorsement is implied.

Workshop Principle: Everybody is ignorant, only on different subjects -- Will Rogers Or I don’t know everything and neither do you, so let’s learn from each other (a.k.a. – when I’m wrong, let me know)

Workshop “Rules” It’s called a workshop on purpose Ask any question, at any time Be a constructive skeptic

What animal is the primary above-ground herbivore in a grassland biome in North America?

Role of Grasshoppers in a Prairie Ecosystem in a Prairie Ecosystem Natural “mowers” stimulate plant growthNatural “mowers” stimulate plant growth Nutrient cyclingNutrient cycling Food for many prairie animalsFood for many prairie animals

Biology of the Species of Concern Grasshoppers may be an important component in the diet of Sage Grouse chicks

Snakeweed grasshopper Cudweed grasshopper Weed Biocontrol Agents? Some Grasshoppers ARE Beneficial!

Plains Lubber EbonyTwostripedRainbow Diversity >450 species in N.A. ≈170 species in NM

PESTS!

BIOLOGY & ECOLOGY Taxonomy Class: Insecta Order: Orthoptera (22,500 species; 1,015 – in N. America) 1,015 – in N. America) Close relatives:Blattodea (Cockroaches) Mantodea (Praying Mantises) Dermaptera (Earwigs)

Taxonomy Order Orthoptera Suborder CaeliferaSuborder Ensifera (short-horned) (long-horned) (short-horned) (long-horned) GrasshoppersKatydids

NOT Grasshoppers katydids crickets Straight ovipositor Curved ovipositor

Is Mormon Cricket a grasshopper? a grasshopper?

Mormon cricket is neither a grasshopper nor a cricket… …it’s a A KATYDID! Anabrus simplex

Grasshopper Taxonomy Family: Acrididae Subfamilies: - Melanoplinae (spurthroated), - Gomphocerinae (slantfaced), - Oedipodinae (bandwinged), - Romaleinae (lubbers), - Cyrtacanthacridinae (bird grasshoppers) Genera: ≈70 in New Mexico Species: ≈ 170 in New Mexico, >450 in Western US

GRASSHOPPER PESTS IN THE WEST - economically important in 17 western states pest species (out of >450) - annually remove 20-22% of rangeland vegetation - estimated average loss $400 million per year - forage losses in 2000 in Texas: $190 million - require vast areas to be chemically treated (up to 20 million acres per year during outbreaks)

What to Expect in 2006? Rangeland Grasshopper Hazard Map

Grasshopper Biology All you need to know in order to get rid of unwanted dinner guests

final molt egg-pod nymphal instars 1 to 5 ~ d egg-laying Life cycle mating flights 1 st instar - critical stage for GH survival (up to >90% mortality)

Development One generation per year = univoltine One generation per year = univoltine Oviposition mostly in soil Oviposition mostly in soil 1-4 egg-pods per female 1-4 egg-pods per female 5-40 eggs per egg-pod 5-40 eggs per egg-pod

Twostriped grasshopper Grasshopper Egg-pods

Biology & Ecology Seasonal Development Typical: - hatching in spring - nymphal and adult development in summer - overwinter as eggs Some species:- overwinter as late-instar nymphs - adults in early summer (usually, band-winged species)

Development: Gradual Metamorphosis Nymphal instars: 5 (rarely 4) Adult

Developmental stages Adult Nymphal development: days (~1 wk/instar) Clearwinged grasshopper

Nymph or Adult? N NA A

Wing Venation NYMPHADULT No cross veins A lot of cross veins

Physiology and Behavior Feeding: Herbivores (necrophily & scavenging) 50% of total consumed by adulthood Adults: feeding on flowers and seeds Feeding is “constant” in assemblage Movement: Primarily walking (1-3 m/day upwind) Flight for escape and dispersal Migration due to crowding and genetics Biology & Ecology

Food Preferences & Feeding Habits Grass feeders: Slantfaced and many Bandwinged species (Aulocara, Ageneotettix, Camnula, Arphia) Forb feeders: many Spurthroated species (Melanoplus foedus, M. angustipennis, Hesperotettix viridis) Mixed feeders: many Spurthroated species (Melanoplus sanguinipes, M. bivittatus, M. differentialis). Truly polyphagous; high economic importance Mormon cricket: may feed on >400 plants but prefers forbs

1 in 1 ¾ in Comparative size Twostripedfemale 1.1 g Clearwingedfemale 0.6 g

In a habitat, grasshopper population consists of several (usually 5-20) species Often, 1-4 species occupy a predominant position accounting for >50% of total grasshopper population Assemblages Biology & Ecology

Clearwinged grasshopper

Population Dynamics Normally: Grasshopper dynamics are regulated by abiotic (weather) and biotic (natural enemies) factors, but if they fail… Normally: Grasshopper dynamics are regulated by abiotic (weather) and biotic (natural enemies) factors, but if they fail… …Outbreaks!: Last for 1-4 yrs, occur at irregular intervals - every 4-10 yrs Warm/dry conditions in the summer are particularly favorable for outbreaks Anthropogenic effects (overgrazing and insecticides) Biology & Ecology

Slower developmentSlower development More susceptible to diseases and natural enemiesMore susceptible to diseases and natural enemies Higher mortalityHigher mortality Less eggs producedLess eggs produced Less damaging Weather: Direct and Indirect Effects

Faster developmentFaster development Less susceptible to diseases and natural enemiesLess susceptible to diseases and natural enemies Lower mortalityLower mortality More eggs producedMore eggs produced More damaging Weather: Direct and Indirect Effects

Population Dynamics Spatial: - Outbreaks clumped in space - Association with static features (e.g.,soil type) - May spread from localized “hot spots” Biology & Ecology

Natural Enemies Predators

Egg predators Egg predators Diptera Bombyliidae Diptera Bombyliidae Bombyliidae larvae Blister beetles

Internal parasites (nematodes) Internal parasites (nematodes) Grasshopper parasitized with a mermithid nematode Nematode egg and larva Natural Enemies

Parasitoids Parasitoids Wasp Scelio sp., Egg parasitoid Flies (Muscidae, Tachinidae) Parasitoids of nymphs and adults Natural Enemies

Predator “saturation”

Biology & Ecology Bionomics Damage: Primary concern is rangeland Movement into cropland is relevant Control: Economic Injury Level = = Damage > Treatment cost Economic Threshold = = 20, 3rd-4th instars per sq. yd Variation with timing, species, efficacy, cost, etc.

Bionomics Other: Cultural (grazing, plowing, planting) Mechanical (crushing) Integrated Pest Management Future: Fewer external resources with more environmental concern, economic demands, people, need for control, and change Biology & Ecology

Purpose of Management Emerging Philosophy: The purpose of grasshopper management is to keep good stewards on the land – to keep those people who live with the Land, on the Land. National Grasshopper Management Board

Integrated Pest Management IPM is an approach that substitutes knowledge and information for materials and external inputs: Essential components: MonitoringDecision-making Methods & Materials

The 3-Phase Approach to Grasshopper IPM Endorsed by the National Grasshopper Management Board

Prevention: Range management practices (“twice over” livestock grazing) have been shown to yield habitat conditions that both: produce more forage and yield fewer grasshoppers Twice-over vs. 5-month season-long grazing: ~300 lbs/acre more herbage biomass 66 to 75% reduction in grasshopper populations 66 to 75% reduction in grasshopper populations

BUT, IfPrevention fails …

Intervention: Efficient survey combined with treatment of incipient infestations or “hot-spots” has been shown to prevent the expansion of grasshopper infestations into large-scale outbreaks

BUT, IfIntervention fails …

Suppression: The use of Reduced Agent-Area Treatments after analysis with CARMA allows rangeland grasshopper control to yield: significant economic profits significant economic profitswith minimal environmental harm minimal environmental harm

Putting the “I” in IPM Prevention survey/sampling + cultural control Intervention survey/sampling + decision support (forecasting) + hot-spot chemical control Suppression survey/sampling + decision support (economic model) + chemical control + conservation biological control

Accurate and Timely Survey is Critical for Efficient Control Grasshopper density assessment Grasshopper density assessment Species composition Species composition Developmental stages (age structure of population) Developmental stages (age structure of population) Acreage infested Acreage infested Egg-bed location Egg-bed location