1. Pest, Plagues & Politics Lecture 18
Locust Plagues

2. Key Points: Locust Plagues
Historical perspective
European/African Locusts
American Locusts
Grasshopper VS locust
Development of controls

3. The fields are ruined; Despair you farmers;
“They have left my fig trees broken;
The fields are ruined;
Despair you farmers;
Like a blackness spread upon the mountains a great and powerful army comes.”
Joel, chapter 1

4. Depictions of locust plagues in the USA

5. A thing of the past?? 2002-12 – Locust Plagues Afghanistan Kazakhstan
China
Chad
Australia
Grasshopper problems in mid-western U.S.

6. A thing of the past??

7. West Wind
East Wind

8. Invasion area: where they breed and come from, usually more resources
Recession area: areas they go to

9. Grasshopper Glacier located 70 miles southwest of Billings, MT

10. Locust in Oregon??? {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!!

11. 1874 Rocky Mt. Locust “Plague”

12. Another flick
from 1975
But “locusts” are
only a metaphor

13. Locust Philately

14. Here she is: Schistocerca gregaria
The infamous Desert Locust

15. Orthoptera Taxonomy or what’s the dif
Orthoptera Taxonomy or 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.

16. Locust 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.

17. Grasshoppers & 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

18. *Grasshopper to Locust Transition

19. PNW Grasshopper/Locust Control Philosophy (ODA et 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)

20. 19th Century American control
Locust collecting device
19th Century American control

21. Flag wavers guide immature locusts into trap

22. Grasshopper/Locust Control Philosophy (ODA et 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)

23. Grasshopper/Locust Control Philosophy (ODA et 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

24. Oregon Grasshopper Control History

25. Oregon 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)

26. Oregon Grasshopper Control History - 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

27. Wiser 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:
Malathion
Penn-cap M
Sevin
RAAT

28. *RAAT Reduce Agent/Area Treatment
One-half of the normal insecticide dosage on one-half of the acreage.

29. Newer control methods Bio-cides Entomopathogenic agents Nosema locusta
A microsporidian that targets Orthoptera
Metarhizium anisopliae
A fungus that targets Orthoptera

30. Key Points: Locust Plagues
Historical perspective
European/African Locusts
American Locusts
Grasshopper VS locust
Development of controls