[Market-farming] Bats for cucumber beetles

Steve Diver steved at ncat.org
Tue Nov 28 10:56:31 EST 2006

Last summer I talked to several farmers that *rely*
on bats for control of moth insects in pecan orchards
(hickory shuckworm, pecan nut casebearer) and
apple orchards (codling moth)... by erecting bat

While updating the ATTRA publication on organic
control of cucumber beetles I found the following data
on "how many" cucumber beetles (Diabrotica + Acalymma spp.)
a bat colony might consume in one growing season.

John O. Whitaker, Jr., a vertebrate ecologist at Indiana
State University, using data partly derived from studies
on the evening bat (Nycticeius humeralis), first estimated
that a typical midwestern colony of 150 big brown bats
(Eptesicus fuscus) might consume 38,000 cucumber beetles,
16,000 June bugs, 19,000 stink bugs, and 50,000
leafhoppers in one season. 

However, in a detailed follow-up study where he dissected
fecal pellets of big brown bats from Indiana and Illinois,
Whitaker calculated that a colony of 150 bats might consume
600,000 cucumber beetles, 194,000 scarabaeids,
158,000 leafhoppers and 335,000 stinkbugs in one season. 

Assuming that half of the cucumber beetles were female,
and using a value of 110 eggs per female, this calculates
to the potential destruction of 33,000,000 diabrotica larvae. 

Fyi, a bat house can attract 150 to 300 bats.

Fyi, a bat apartment can attract "thousands" of bats.

Spraying newly erected bat housing with bat guano can
help attract early dwellers.

An April-June 2006 article in California Agriculture evaluated
the best way to attract bats to farms through the placement,
shape, size, and color of bat houses. 

Fyi, Frank Bibin the pecan grower in Georgia who keeps
sixteen bat houses collects one to two 55-gallon barrels
of bat guano each year.   The guano is digested with a
microbial blend and used as a biofertilizer.

Whitaker, J.O., Jr.  1993.  The status of the evening bat,
Nycticeius humeralis, in Indiana.  Proc. Indiana Acad. Sci. 
Vol. 102.  p. 283-291.

Whitaker, J.O., Jr.  1995.  Food of the big brown bat
Eptesicus fuscus from maternity colonies in Indiana
and Illinois.  American Midland Naturalist. Vol.134,
No. 2.  p. 346-360.

Long, Rachael F., W. Mark Kiser, and Selena B. Kiser. 
2006.  Well-placed bat houses can attract bats to
Central Valley farms.  California Agriculture.  April-June. 
p. 91-94. 


Steve Diver

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