A meteorological and entomological investigation

DID A LATE APRIL SNOWSTORM END THE

MINNESOTA GRASSHOPPER PLAGUES OF THE 1870’S?

A meteorological and entomological investigation

Motivation From St. Cloud Visitor’s Guide:

“Grasshopper Chapel: The Chapel represents the miracle of an 1877, April 26 snowstorm that halted an impending grasshopper plague.”

Many print and Web documents assert that a spring snowstorm and cold weather destroyed the grasshoppers

Question: was there really such a spring snowstorm, and what effect might it have had?

Actually, two versions of chapel’s origins exist

Version 1: late spring snowstorm killed off grasshoppers; chapel built in thanksgiving

Version 2: weather not a factor; local parishioners seeking divine assistance in ending grasshopper plague promised to build chapel and hold services there for 15 years

First, a look at the grasshopper plague of the 1870’s

Starting in 1873, farmers in Minnesota were severely affected by successive infestations of grasshoppers

1873

Region of extensive

grasshopper damage

1874

18751875

1876

1873 1874 1875 1876 18770

2

4

6

8

10

12

14

16

18

20

Minnesota Average Wheat Yield, 1873-77

state averagegrasshopper coun-tiesbushels/acre

Extent of damage in 1874 (worst in green)

Meet the Rocky mountain locust (Melanoplus spretus)

No photos from life since it’s long extinct (1902)

This species resembled the common grasshopper but was called a locust because of its migratory behavior.

20-35 mm on average

Migratory locust swarms could cover thousands of square miles

Reports of the insects eating every green thing

Even known to eat holes in clothing and chew wooden tool handles

Great hardship resulted; many pioneers were already living a life of subsistence

Some families abandoned their claims Men went east to find work

In "The Funston Homestead“ (Kansas), Ella Eckdall writes:

All was going well on the farm and Father's hopes were high until one morning in the spring of 1874, when great black, threatening clouds rolled in from the west. The landscape suddenly darkened, and from the dark mass great hordes of grasshoppers descended upon the growing fields. They voraciously devoured every green thing above the ground. Not a spear of grass nor a leaf upon tree or plant was left to mark the once verdant herbage.

Laura Ingalls Wilder gave an description consistent with other pioneer accounts

1874-76 homestead in Redwood County, Minnesota

She describes the insects devouring the field and garden crops (with the sound of ''millions of jaws biting and chewing'‘)

Examples of crop damage

Oats damaged by lesser migratory locusts

Wheat field damaged by Australianplague locusts

Control was difficult if not impossible No pesticides were available Various tactics were tried

capturesmokeburningditches“hopperdozers”

hopperdozer

Next, a look at Grasshopper Chapel (Assumption Chapel)

Located on a hill on the outskirts of Cold Spring, Minnesota (15 miles SW of St. Cloud)

tympanum

grasshoppers kneeling in submission

Original chapel probably looked something like this one, a second “grasshopper chapel” built in the same summer, just south of St Cloud

Evidence for Version 1 (snowstorm)

Official Army Signal Corps records are few; observers at widely scattered sitesFort Ripley data (50 miles north of St Cloud)

is bad Reports on a widespread late April storm

with snow, sleet, and rain found in newspapers

29.59” = 1002 hPa

6” storm total at

Genoa, NE

996 hPa

18”

0.5”6”

1”

10”

0”

sev”

1.74L”

0.64L”

St. Paul observations

Apr 24, 1877 55 36 Apr 25, 1877 62 40 Apr 26, 1877 56 45 Apr 27, 1877 46 33 Apr 28, 1877 39 32 0.13/0.25 melted Apr 29, 1877 45 30 Apr 30, 1877 54 26 May 1, 1877 60 37

Mean almost 2 SD below average

But are snow and (possibly) subfreezing temperatures injurious to grasshoppers?

Life cycle of the grasshopper Eggs laid in late summer or fall Overwinter in ground Hatching in early May Nymphs develop wings after 40-60 days Adults can then fly to a new area and lay

eggs to repeat the cycle

Effects of cold on grasshopper nymphs

Studies of related species such as Melanoplus sanguinipes show that warm early spring with premature hatch followed by cold snap

○ poor development of nymphscloudy, wet weather

○ favors occurrence of disease○ inhibits feeding and results in high mortality

What of a short, near freezing period? Many insects exhibit ‘cold hardening’ (they

accumulate sugars to prevent tissue freezing; locusts may have had this capacity.

Air temperature of 32°F is not generally lethal to grasshoppers, as they often shelter.

Hemolymph and tissues of insects include salts and carbohydrates that would prevent freezing (and lethality) at this temperature.

“Grasshoppers can certainly survive temperatures in the 20s” (Lockwood, personal communication).

Observations at the time? Newspaper accounts record varying

opinions, but observations showed the storm had little or no effect on the insects

Point may be moot: had eggs even hatched in central Minnesota?

Again we rely on newspaper reports While hatching had commenced in

southern Minnesota, only a few eggs had hatched in the St. Cloud area by the time of the storm

Evidence for grasshopper damage in the summer of 1877 Many newspaper reports from area Archived statement of Fr. Leo Winter

(pastor of the parishioners building the Cold Spring chapel)

Wheat yields for Stearns County1875 1876 1877 1878

Acres 39600 46000 48700 57900

Bushels 572600 384100 143800 902000

Bu/ac 14.5 8.35 2.95 15.8

1877

1877 was the last year of the grasshopper plague in Minnesota (and elsewhere)

They flew but didn’t land to lay eggs Why?

Disease, parasites, or cool and wet June may have taken a toll

Fate unknownMigration back to Rockies?

Population dynamics

Current population models show success in predicting population increases, but cannot predict population crashes

Latter are influenced by weather, and long-range weather forecasting is poor (as we know!)

Conclusions

Recall the two versions of the Grasshopper Chapel’s origin:Version 1: late spring snowstorm kills off

grasshoppersVersion 2: weather not a factor in

disappearance Strong evidence indicates Version 2 is

the true story

Questions?