Pest, Plagues & PoliticsPest, Plagues & PoliticsLecture 18Lecture 18

Locust PlaguesLocust Plagues

Key Points:

Locust Plagues

• Historical perspective

• European/African Locusts

• American Locusts

• Grasshopper VS locust

• Development of controls

“They have left my fig trees broken;They have left my fig trees broken; The fields are ruined;The fields are ruined; Despair you farmers;Despair you farmers; Like a blackness spread upon the Like a blackness spread upon the

mountains a mountains a great and powerful great and powerful armyarmy comes. comes.””

Joel, chapter 1

http://www.roundtree7.com/2012/04/alberts-swarm/

A thing of the past??A thing of the past??

• 2002-12 – Locust Plagues2002-12 – Locust Plagues– AfghanistanAfghanistan– KazakhstanKazakhstan– ChinaChina– ChadChad– AustraliaAustralia– Grasshopper problems in mid-western U.S.Grasshopper problems in mid-western U.S.

http://www.google.com/hostednews/afp/article/ALeqM5gbDXumh4HxdqmVQyWMmdt-z8k6mw?docId=CNG.a7f5868b3661b5beedfbba67acac7c9c.5b1

A thing of the past??A thing of the past??

http://en.tengrinews.kz/kazakhstan_news/Tajik-locusts-threaten-Kazakhstan-crops-2463/

West Wind East Wind

http://www.sciencedirect.com/science/article/pii/S0022191010001460

Grasshopper Glacier located 70 miles southwest of Billings, MT

http://formontana.net/grasshopper.html

Locust in Oregon???Locust in Oregon???{absolutely}{absolutely}

• For many thousands of years before there was a “political” Oregon.

• Melanoplus spretus - the Rocky Mt. Locust

• Now extinct!!– Evidence of locust swarms found in Wyoming

glacial deposits which are 840 ± 85 yrs B.P.– Locust remains in layers measured in feet!!

1874 Rocky Mt. Locust 1874 Rocky Mt. Locust ““PlaguePlague””

http://wyofile.com/2010/11/3507/

Another flickAnother flickfrom 1975from 1975

But But ““locustslocusts”” are areonly a metaphoronly a metaphor

Locust Philately

Here she is: Schistocerca gregariaThe infamous Desert Locust

Orthoptera Taxonomyor what’s the dif. Between a grasshopper and a locust

• Order Orthoptera (straight wing)– 30,000 species– includes the grasshoppers, locusts, katydids &

crickets– family: Acrididae (most grasshoppers & locust)

• 8,000 species worldwide with only a FEW as pests

• A locust is a MIGRATORY & GREGARIOUS grasshopper.

LocustLocust

• Notorious creatures with a long history of human interactions– One of the putative biblical plagues – Biblical references:

• 10 for grasshoppers

• 24 for locusts

– Ergo, these insects were very familiar to ancient civilizations.

Grasshoppers & LocustGrasshoppers & Locust

• Univoltine• Hemimetabolous (incomplete metamorphosis)

– egg; nymph (normally 5 nymphal stages) - adult

• Over-winter in the egg stage

• Locusts are found on every continent (well, with the exception of Antarctica)

Melanoplus devastator - the devastating grasshopper

*Grasshopper to Locust Transition*Grasshopper to Locust Transition

Solitary grading to Migratory

Lighter in color Darker in color

Longer hind legs Shorter hind legs

Shorter wings Longer wings

Sedentary Gregarious

http://michaelscomments.wordpress.com/2009/09/19/cicadas-vs-periodic-cicadas-vs-grasshoppers-vs-locusts/

PNW Grasshopper/Locust Control PNW Grasshopper/Locust Control Philosophy (ODA Philosophy (ODA et aliaet alia))

• Control programs began in the 1930ties

– sodium arsenite (a dry bait)– sodium fluosilicate (as a wet bait)– nicotine sulfate

• killed grasshoppers effictively as well as three applicators one day in the Ephrata area of Washington in 1939

• Post WWII into the early 1960ties

– widespread use of CHs (dieldrin, aldrin, chlordane & heptachlor)

1919thth Century American control Century American control

Grasshopper/Locust Control Philosophy (ODA Grasshopper/Locust Control Philosophy (ODA et aliaet alia))

• Era of CH use– standard rate of application was 1/2 oz. per acre

mixed in 1 gal. of diesel oil– residual buildup a big problem in

environmentally sensitive areas such as the Malheur Wildlife Refuge

• 33,000 acres treated with dieldrin in 1962 against the clear-wing grasshopper (Camula pellucida)

Grasshopper/Locust Control Grasshopper/Locust Control Philosophy (ODA Philosophy (ODA et aliaet alia))

• Mid-1960ties

– A move away from chlorinated hydrocarbons to the “hot” organosphosphate materials.

• e.g., malathion– The inclusion of the carbamate family of

insecticides

• e.g. Sevin

Oregon Grasshopper Control HistoryOregon Grasshopper Control History

1985 Malheur 494,950 Malathion 1986 Baker,

Malheur & Union

966,810 Malathion & Carbaryl

1989 Lake 12,800 Malathion 1990 Lake 11,230 Malathion 1992 Harney 25,640 Malathion 1993 Klamath 11,300 Malathion

Oregon Grasshopper Control HistoryOregon Grasshopper Control History

• 2008– 1,130,000 acres considered infested at an

economic level– Average infestation was 29 GH/sqy– Treatments used a 5% Sevin bait & Dimilin

in environmental sensitive areas (Malheur)

Oregon Grasshopper Control History Oregon Grasshopper Control History - Conclusions- Conclusions

• Reliance on one method of control

– CHEMICAL

• Control programs in northeast, south central and eastern Oregon– regions of lowest human density– agriculturally based regions

Wiser use of insecticidesWiser use of insecticides

• Western range lands– 50 species of grasshoppers– Of which 9 cause 95% of the damage

• Economic thresholds– 8 to 40 hoppers per square yard

• Chemicals most frequently used:– MalathionMalathion– Penn-cap MPenn-cap M– SevinSevin

• RAAT

*RAAT*RAAT

• RReduce AAgent/AArea TTreatment• One-half of the normal insecticide dosage

on one-half of the acreage.

Newer control methodsNewer control methods

• Bio-cides– Entomopathogenic agents– Nosema locustaNosema locusta

• A microsporidian that targets Orthoptera

– Metarhizium anisopliaeMetarhizium anisopliae• A fungus that targets Orthoptera

Key Points:

Locust Plagues

• Historical perspective

• European/African Locusts

• American Locusts

• Grasshopper VS locust

• Development of controls