The Insect pest survey bulletin

MISSING IMAGE

Material Information

Title:
The Insect pest survey bulletin
Physical Description:
v. : maps ; 26 cm.
Language:
English
Creator:
United States -- Bureau of Entomology
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
Bureau of Entomology, U.S. Dept. of Agriculture
Place of Publication:
Washington, D.C.
Publication Date:
Frequency:
monthly, mar-nov. plus annual[1926-]
monthly, apr.-nov.[ former 1922-1925]
monthly, may-nov.[ former 1921]

Subjects

Subjects / Keywords:
Insect pests -- Periodicals   ( lcsh )
Entomology -- Periodicals   ( lcsh )
Genre:
serial   ( sobekcm )
federal government publication   ( marcgt )

Notes

Dates or Sequential Designation:
Vol. 1, no. 1 (May 1, 1921)-
Numbering Peculiarities:
Vol. 14, no.9 issued only as a supplement..
Issuing Body:
Vols. for May 1, 1921-1934, issued by the U.S. Bureau of Entomology; 1935- by the U.S. Bureau of Entomology and Plant Quarantine.
General Note:
"A monthly review of entomological conditions throughout the United States" (varies slightly).
General Note:
Includes annual summary starting in 1926.
General Note:
Includes some supplements.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030368280
oclc - 08816534
lccn - sn 86033699
Classification:
lcc - QL1 .I56
System ID:
AA00023228:00119

Full Text





THE INSECT PEST SURVEY

BULLETIN


Volume 17 Supplement to Numfer 1 March 15, 1937


BUREAU OF

ENTOMOLOGY AND PLANT QUARANTINE

UNITED STATES

DEPARTMENT OF AGRICULTURE

AND

THE STATE ENTOMOLOGICAL

AGENCIES COOPERATING


U, Vt*'" RO0
















Digitized by the Internet Archive
in 2013










http://archive.org/details/insect1937supp1










PEST SURVEY


Vol. 17 Supplement to -'uj.ber 1 :.arch 15, 1937



ALFLT'A "-WIL SURV-,Y,I- FAlL 0F 1936

W. C. EcDuffie, Junior Entomoloist
Division of Cereal and .Forage Insect Investi 7ations2
Bureau of -Ztomolo qy and Plant Quarantine
U. S. Department of Azriculture




PURPOSE OF SLUVjTY

Fall survey of alfalfa weevil -ibuir.'.r.ce was initiated in 1932 in order
to indicate the outlook for damage in the following year and to build a
reliable record of annual regional abundance which may later be used in
studying effects of climate on the weevil. The abundance of overwintering
cocoons of the larval parasite Batayplectes curculionis Thos. was obtained
from survey samples and the percentage viability of these was determined by
dissection.

.A-.7"T OF SJRVTi

Districts surveyed were restricted to those regions most important
both in regard; to alfalfa and to prevalence of weevil damage in recent
years. Twelve districts were surveyed. These included parts of Oregon,
Idaho, Colorado, Inevada, Utah, and Tebraska. The sampling plan wes modi-
fied from that used in previous years in that the number of sarnles per
field were reduced and thie number of fields in a district were increased.
Four samples were taken in each field and 25 fields in each district. This
gave a less accurate figure for each field but a more useful indication of
the general level of weevil abundance in a region.


IHypera postica Gvll.
2The wor: on which this report is based was carried out under the
direction of J. C. Hamlin. Trie author was assisted by F. V. Liebenman,
R. C. Newton, R. W. Bu3nn, and L. J. Jones.


-29-


BUIIETIN


I N S E C T





-30-


IM5THODS

Bach sample consisted of all trash, alfalfa crowns, and soil to a
depth of 2 inches inside a metal die 1 foot square. The volume of samples
was reduced by washing, so that weevils, parasite cocoons, and a small
amount of litter remained in the lower of two screen-bottom tubs. Washed
samples were wrapped in absorbent paper towels and, when dry, were examined
in the laboratory.

LIMITATIONS OIT US. OF? DATA

A mean of two adults per square foot is considered necessary to produce
economic damage in most of the older weevil-infested territory. However, the
extent of damaTe in any locality is subject to modification by the character
of the spring weather; that is, the severity of damage depends on whether
the weather is favorable or unfavorable for weevil development. Field condi-
tions, such as thin stands and poor growth, may also modify damage in any
field and in any district where such conditions are prevalent, because fewer
adults will produce the larval concentration necessary to cause damaFe.
Furthermore, injury in any field having menacing numbers of adults is in-
creased by delay in cutting, owing to unfavorable haying weather or to inter-
ference with other farm duties, after the plants are mature. This is indi-
cated by the appearance of basal shoots and scattered blossoms.

RESULTS

Results follow according to States, accompanied by brief discussions
of the areas surveyed and the extent of damage in 1936. The sampling data
are tabulated by districts and each tabulation is accompanied by a brief
interpretation. All avera-es have reference to areas of 1 square foot.

0RDGO 15

Damage in Oregon last season was prevalent in Jaclcson County and in
Eagle Valley, Baker County; consequently these areas were surveyed in the
fall. Although there was virtually no damage in Malheur County, some of the
farmers thought that the weevil might be building up to damaging populations
again. For this reason :>-hYcur County was also surveyed, being treated with
Eagle Valley as one district.

Ma,le Valley. Baher County.-- Adult populations were small indicating
only slight da2.iage new.t season. Only three fields showed populations of one
or -.:ore adults, which normally would not be sufficient to cause damage, but
in this area slight injury may occur in the hillside fields, owing to thin
stands and poor gronvth. Cocoons of 3. curculionis wore rAtaor scarce but,
in view of the rather small weevil populations this parasite promises to be





-31-


effective in minimizing the production of adults in 19D77. Re,:ults of t-e suir-
vey in "a;-le Valley, sa:-pled on October 10, are sho,1 in the following : table.


.. curculionis cocoons


?ield No.


2

4 - - -
5
6
7 -:
3
9--
10--
11---
12-----

Average


adu1 t s
lu ber

-.-5
0
.75
.75
1.00
I. 7oo
.75
.50
75
1.25
-.50
.50


O.S 7


Present
-ur-be r
2. 00
2.75
1.75
2.00
1.50
6.00
3.25
1.00
2.50
2.75
1. 50
75


SViable
Percent
52.50
45.45
42.86
12.50
0
16.67
0
25.00
50. 00
45.45
83. 33
66.67


2.31


l'ial_,eur Cou,-. "'.Ve-o.vi adults were et rre.,el- scarce, bei:'.. found in
only t2iree fields and averaQ'in- onl- 0.08, .ici i r.icated no da-r.a~- for 1937.
3. curculionis cocoons were scarce, avera'iin,- only 0. 9, but this. avera e is
lar -e, co:iLared with t'.e weevil population. Results of the sure" in Ialheur
County, samipled on October 11-12, were as follows:


2 - -
2 - -
4 - -

7 - -

5 - -
9 - -

10 - -
11 - -
12 - -
13 - -
2--

4--
5--

7--
8--
9--


12 -- -
13 -- -


H. postica
adults
1.,umoer
0
0.25
0
.25
C
0
50
0
0
0
0
0
0


3. curculionis
Present
Ni-rzu e r
0
0.25
.75
2.00
0
.25
.25
.50
1.25
.50
3.50
2.75
.50


Aver -e : 0.08 0.95 : 42.00

Jackson County.-- Adult populations indicated that about one-fifth of
the fields will be damaged in 1937. Populations necessary to produce d e
are not definitely known, but more adults are required thin in the older in-
fested areas, because of climatic factors. Ihc recently introduced parasite
has spread rapidly, cocoons having, been recovered in 18 of the 25 fields


cocoons
Viable
Percent

100.00
33. 3


0
0
50.00
20.00
0
20.57
81.82
50.00


Field No.





-32-


surveyed. Although the populations are still small, they have increased
satis-actorily to date. In the following t.2ble are shown the results of
the survey in Jackson County, sampled from October 14 to November 14.

H. postica B3. curculionis cocoons -
Field No. : adults : Present Viable
S Number Number Percent
1 ----- 1.00 7.75 : 29.03
2 .25 : .50 0
3 .50 1.75 : 14.28
4 .25 0 : -
5 .25 0 -
6 - - 1.00 : .50 50.00
7 -- 2.25 .25 : 100.00
8 2.00 4.50 : 61.11
9 - 2.00 2.75 : 90.91
10 ---- 2.75 : .25 : 0
11 - .50 1.00 75.00
12 .75 0 -. -
13 1.50 .25 : 100.00
14 - - 1.00 1.50 50.00
15 ---- .50 0 --
15 1.25 .25 : 0
17 ----- 1.75 1.00 : 25.00
18 3 2.25 1.00 25.00
19 - - -: 1.50 1.25 40.00
20 - - -: .75 .25 100.00
21 - - : .50 0 : --
22 - - .50 : .25 : 100.00
23 - - : 0 0
24 - - -: .25 0 --
25 ----- .50 : .75 100.00
:. I
Average 1.03 1.03 3: 6.60

IDAHO

Damage in Idaho last season was. negligible, less than 1 percent of the
fields bei:n injured. However, larv-al populations were sufficient to, possi-
bly, produce dumging numbers of adults in both the eo.stern and western parts
of the State; and consequently those areas were surveyed last fall.

Eastern Idaho.- The survey in eastern Idaho covered parts of five
counties, Bingham and Bonnevlle Counties being considered as a subdistrict
and Jefferson, Madison, and Fremont Counties as another These divisions were
deemed necessary because of differences in clinato, the three northern coun-
ties i v'riably ivi.vf colder winters and more snow than the other two.
Although the entire eastern section is considered a two-crop area, occasion-
ally, as was the case this season, three crops can be cut in the two southern
counties. In the northern counties, particularly Madison and Fremont, only
two crops are cut in any season. Adult populations indicate only light damage
in 1937, muenacing populations being present in less than one-fifth of the fields.








B. curculionis cocoons were rather scarce 'jbut this parasite promises to be
effective next season. The following table shows results of the survey in
Bonneville and Bingham Counties, sampled on September 22-24.


Field No.


2 - -
3 - -
2--
3--
4
5
6
7
8
9-
10
11
12
13 - -

Av erag


*
*

*





:
- I


_- I


H. postica
adults
ITunh e er
3.25
1.50
2.00
.50
.50
.75
.25
.50
0
.25
.25
.75
.50


0.85


3. curculionis
Present

3.25
6.75
3.50
23.25
8.50
.75
0
.50
0
.25
.50
10.75
15.50


3.60


cocoons
Viable
Pcrc ent
46.15
14.81
35.71
12.90
8.82
66.67

50.00

0
50.00
30.23
6.45


S 26.74


Adult populations indicate considerable damage in 1937, menacing
populations being present in almost half of the fields. 3. curculionis
cocoons averaged 5.85 per square foot and may be sufficiently numerous to
be effective, at least during the early part of the 1937 season. In the
next table are given results of the survey in Fremont, `adison, and Jefferson
Counties, sampled on Septe-mber 22-24.

H. postica 3. crculionis cocoons
.Field No. : adults: Prescnt : Viable
ilamunb e r :iNnber Perc ent
14 - 1.00 3.75 0
15 - - .25 1.00 50.00
16 - - .25 : 6.25 : 12.00
17 - - 1.25 14.00 : 10.71
18 - -: .50 1.00 25.00
19- - - .25 4.28 47.06
20 - - 2.00 1.25 20.00
21 - - 4.50 : 8.25 : 12.12
22 - - -: 2.25 : 3.75 33.33
23 - - 1.75 : 15.50 : 4.84
24 - - 2.50 : 4.50 22.22
25 2.75 6.75 7.41

Average : 1.60 5.85 13.88


Canyout County.--0bservat ion in
Id-Iio last season revealed comparable


the lo'.ver S:--a-c River Valley of western
conditions in Ada, Gem, Canyon, Payette,


and Washi,1iton Counties. As a result, the fall survey w.s limited to C-.nyon
County, which contained the largest alfalfa acreage. Adult populations wore
small, no fields having nenncing numbers. 3. turculionis cocoons were scarce






-34-


but, in view of the small weevil populations, the parasite promises to be
effective in 1937. Results of the survey in Canyon County, sampled on


October 13-15, were


as follows:


Field. 1


ro. ___;__




*4


-" *'


- w- I

- - -- F



- -R a
.- < - F




F
- F



- -" F


Average ;


0.35


1.51


. 33.77


UTAH


The survey in Utah included Box Elder, Salt Lake, Sevier, and
Sanpete Counties, which are among the most important and most persist-
ently damaged areas in the State. Damage, even in these counties, last
season was slight, but larval populations were sufficiently large in each
possibly to produce menacing adult populations.


-"- "***""****** l"f
*
*


1 -
2
3
4
5
6
7
8
9-
10 -
11 -
12-
13 -
14-
15 -
16 -
17-
18 -
19 -
20 -
21-
22 -
23 -
24-
25 -


cocoons


H. -postica
adults
NTumoe r
0.50
1.50
0
0
.25
.25
1.25
0
0
1.00
0
0
0
0
0
1.00
0
.25
.50
.50
.75
.25
.25
.50


a,





F


F'
a.
F.
F,

F
a



F
a






a
F-


3. curculionis
Present
NTumber
3.00
0.50
0
1.00
1.00
1.50
3.00
.50
0
3.25'
.50
0
.50
.75
.75
2.75
.50
1.75
.25
4.25
8.75
.25
1.50
.25
1.25


Viable
Percent
41.67
50.00

100.00
75.00
33.33
33.33
0

23.08
0

100.00
33.33
66.66
45.45
50.00
42.86
0
5.88
28.57
0
50.00
100.00
0






-35-


3ox Zlder County.-- Adult populations indicate considerable damarc-
in 1937, one-fifth of the fields having. menacing copulations. 3. curciilionis
cocoons are sufficiently abundant for this parasite to be highly effective
next season as usual. The results of the survey in Box Elder County, sampled
on October 22-25, are tabulated below.


E. postica B. curclulionis cocoon
Field ITo. : adults s Pre sent _:: Viabl4.


I T'wib er
1 - - 1.25
2 4.23
*3 2.25
4 - 0
5 1.00
6 - - 1.25
7 - .50
8 0
9 0
10 0
11 0
12 - -. .50
13 - -.75
14 - - .25
15 0
16 - - 1.50
17 - - -: 2.50
18 - - .25
19 0
20 - - 1.25
21 - -- 1.25
22 - - 1.00
23 - - 2.50
24 - 2.00
25 - 1.00

Average 1.01


IjUmb er
2.75
73.25
15.25
13.75
11.00
13.75
12.75
1.00
:1.25
"0
S50
2.25
"1.00
4.75
0
4.00
12.75
2.75
1.50
11.75
7.50
6.75
2.00
7.00
2.50

5.67


Perc ent
9.09
23.08
29.51
34.55
22.73
40.00
33.73
75.00
20.00

50.00
73.33
75.00
78.95

71.25
33. 33
9.09
83.33
17.21
20.00
25.93
25.00
14.29
20.00


32.77


Salt Ia: Courty. Adult populations indicate considerable danuoJe
next season, appro-im-tely one-fifth of the fields being menvaccd. B. cirr-
culionis cocoons were numerous, indicating the parasite may be axyected
to be highly effective as usual in 1937. Data obtained in the survey in






3.-,O





-36-


Salt Late County, sampled from October 27 to November 11, are summarized in
the following table.


Field No.


2:
4 - - -


5 - - -

7 - -
1----------



8
9 - - -
4- ------ ---


10
11---- -- ----
12 - - -
13 - - --
14-----
15---- --
16---- --
17 - - --
18 ----- --
19---- --
20 - - -
21-----
22-----
23---- --
24 - - -
25 - - -

Averaze -


H. postica
adults
TNumber
0.75
.75
2.50
0
.50
.75
0
1.50
.25
3.50
S.50
1.25
S.75
.50
.25
.50
S.25
1.50
0
1.00
,50
.25
S1.00
2.25
S2.25


B. curculionis coocoons


S


S


* S
4





I

S
2


Present
Tum.ber
5.25
4.50
5.00
8.00
28.50
9.00
6.75
12.25
22.75
32.50
26.00
13.75
13.50
4.00
3.25
. 4.25
3.25
23.25
9.25
7.75
9.25
8.25
11.00
S41.75
5.50

* 12.74


0.93


S
I
S

0
S


S
S





S


Viable
Percent
23.81
16.67
25.00
9.38
6.14
11.11
40.74
14.29
4.40
14.62
19.23
9.09
7.41
18.75
0
23.53
23.08
4.30
37.84
22.58
27.03
39.39
20.45
17.37
9.09


15.31


Sevier- Sanpete Counties.--
aro contiguous, identical in most


Although sampled separately, these counties
respects, and may be considered as one dis-


trict. In Sevier County adult populations ihdicatod slight damage next season,
approximately one-fifth of the fields being menaced. B. curculionis cocoons
were numerous and this species promises to minimize the production of adults in
1937. Results of the survey in Sevier County, sampled on November 5-7, were as
follows;


Field No


2 - - -
3 - - -
4 - - --
3



8 - - -
10 - - -
4 --
6
7--


10--- -- -- --
11---
12--- --- --
13-------
Avwrave -


H. postica
, adult s __
Numb e or
1.00
1.25
2.00
.25
.50
.75
1.00
.25
4.00
.50
0
.75
.25


B. curculionis
Pro sent
Number
8.50
16.75
16,50
24.50
3.75
4.25
1.1.00
6.25
8.50
18.75
2.00
4.50
.75


cocoons
.Viable
Present
5.88
8.96
27.27
30.61
6.67
29.41
22.73
32.00
8.82
8.00
50.00
16.67
33.33


- gV .........9... 6


19.25


0-96


9.6i9






-37-


In Sanpete County, adult populations indicated considerable damage
in 1937, one-third of the fields being menaced. Of the total .area in
the two counties, one-fourth of the fields have menacing weevil popula-
tions. In this county 3. curculionis cocoons were numerous and the
parasite promises to be effective next season, as usual. Results of
the survey in Sanpete County, sampled on November 5-7, are shown in the
following table.


Field No.

1 --
2 - -
3 - -



7 - -


10 - -
11 - -
12 - -
2--
3--
4--
5--
6--
7--
8--
9--


12 ---


* f
- *f






- ft


U. postica
-laults
Number
4.00
1.25
.75
3.25
.75
3.50
2.25
.50
1.25
1.00
.75
.50


3B. curculioris cocoons
Present : Viable
Number Percent
12.75 17.65
8.75 0
9.75 15.38
6.75 33.33
5.25 23.81
15.00 11.67
13.25 13.21
11.75 23.40
16.25 32.31
29.00 6.90
8.75 8.57
21.75 6.90


Average- :


1.65


: 13.25


: 14.47


COLORADO

Last season weevil damage in Colorado :'"s confined to Mesa, Delta,
and Montrose Counties. In Mesa County 75 percent of the fields were
severely damaged, In Delta and Montrose Counties damage wais less severe
and varied in different districts, one having 14-percent damage and
another 90 percent. Consequently, a survey was made last fall in the
more important districts of these counties, Mesa County being considered
as one district and Delta-Montrose Counties as another.


Delta County.-- Adult populations indicated slight daTage n-xt
season. No fields sampled had menacing populations but in many fields
the numbers present closely approximated that necessary to produce dariAa-e.






-38-


The results of the survey in Delta County, sampled September 8-18, are as
follows:


Field. o. '


1-
2-
3-


-

*


4---.

0
7 - -- :
3 :
9 - - r
10 ----- .

Average -:,


H. postica
adult s
Hurnber
1.25
1.50
.75
1.25
1.25
1.25
.75
1.25
1.50
1.75


1..25


SB. curcalionis
: __Prevent :
:iiumber
4.00
8.50
13.00 0
7.00
3.25
9.00
2.75
4.75
1.00
1.25


5.45


Montrose County.-- Adult populations indicated slight
Only two fields actually had menacing adult populations, but
the number closely approximated that constituting a menace.


the survey in Montrose
tabulated below.


damrae in 1937.
in several others
The results of


County, sampled:from September 23 to October 8, are


H. Postica
adults
Number
1.25
1.25
1.00
4.25
.50
1.50
2.00
1.50
1.00
.75
1.00
1.00
1.25
.50
1.00


B. curculioniis
Present
ITumber
2.00
2.25
13. 50
2.25
.75
6.75
8.25
15.00
12.25
5.75
3.00
3.25
4.75
11.00
3.50


cocoons
Viable
Percent
12.50
11.11
11.11
44.44
66.67
18.52
21.21
25.00
4.08
13.04
75.00
7.69
10.53
27.27
21.43


Average -:


1.32


6.28


19.36


Mesa County.-- Adult populations indicated widespread damage in 1937,
menacing populations being present in about three-fourths of the fields. Only
1.5 adults per square foot are necessary to produce damage in this area, owing
to poor stands and growth. Last season's studies in western Colorado indica-
ted that the parasite, although rather numerous, was less abundant and less
effective than in Utah. Parasitization of early larvae was less and the


cocoons


viable
Percent
13.75
5.88
21.15
53.57
30.77
0
18.18
26.32
75.00
0


20.64


Field No.


S






-, -. 9
*- - 9


-. - S
""i, "


o _
*

_

*p
o*


"*


1 -
2-
3-

5--
6--
7-
8 -
9--
10 -
11 -
12 -
13 -
14 -
415 -
15






-39-


effectiveness declined earlier in the season and more rapidly. In view of
these findii-is, the parasite populations are insufficient to be highly effec-
tive in western Colorado next season. In the following table the results of
this survey are presented. This county was sapled from October 14 to
November 23.


?4ield Yo.


1 - -
2
3 - -
4 - -





8 - -
9 - -
10 - -
11 - -
12 -.
13--
14---
15---
16--







17 - -
18 - -
19 - -'
7--
8--
9--








20 - -







21 - -
22 - -
12--








13 - -
14--







2415 - -
16--






2517 - -

18Average -
19 g

21 - -
22 - -


24 ---
25- -


Average -


*
*


- 1>
*
*
_ *
*
--- ... *
*
"~ *
___ *
*
--- --- *
--- --- *
*
---- --t *
*
--- *
*
---. *
--- ^
--- --- *
*
--- --- *
*
--- --. *
*
___ *
--- *
__ ____ *
*
_ ______, *
--- --- ^
--- --- *
*
___ .---I
*
--- ---- *
*
- -;
- ___ *
*
__ --- *

--- *
--- ^

--- *
*
*


6.83


::ZVADA


Reports of slight damiee in western erevada last season, especially in
Washoe and Douglas Counties, prornrted a fall survey of this area, including
Churchill County. Interest centered on Douglas County where, until last
season, the -weevil was ne.*i7-zible. Churcl-ill County was considered as a whole
district, while the others vere considered half-districts.


Dou_ las County.-- Adult populations indicated slight damage in 1937,
one-fourth of the fields having menacin_ numbers of adults. 3. curculionis
cocoons were numerous and sufficient to indicate the parasite's effectiveness
next season if this county is comparable, as it is believed to be, with


: 20.79


H. postica
adults
Number
3.75
:75
2.50
1.75
2.25
2.50
4.00
4.75
1.75
2.50
3.50
2.25
1.50
2.00
.75
3.00
.25
.50
.50
1.00
1.75
3.00
1.50
.75
2.75


3. curculionig
Present
-Tu. ber
'11.50
2.50
10.50
S6.25
3.78
3.00
11.75
15.00
5.25
'11.50
4.50
7.50
3.50
3.75
3.25
1.50
1.50
10.75
12.75
3.25
3.50
1.50
5.00
26.00
1.50


cocoons
Viable
Percent
6.52
20.00
0
40.00
6.67
33.33
40.43
5.00
33.33
41.30
27.78
33.33
7.14
6.67
38.46
16.69
33.33
25.58
1.96
7.69
21.43
0
45.00
18.27
83.33


2.06









Churchill County, where detailed studies have been made. Results of the
survey in Douglas County, sampled on November 20, were as follows:

H ]ostica B. cur-culionis cocoons
Field No. : adults : ..Present : Viable
: Number : Number : Percent
1 0.50 12.50 8.00
2 -0 :.75. 33.33
- 0 : 1.25 : 40.00
4 ----- 0 24.25 : 12.37
5 - .50 10.75 9.30
6 ----: .50 15.50 : 17.74
7 - 7.50 45.25 : 8.84
8 -- .50 : 9.00 27.78
9 --. 2.50 9.00 8.33
10 ----- .50 : 7.00 : 21.43
11 0 6.25 : 28.00
12 - --2.00 4.25 : 11.76

Average 1.20 12.15 : 17..38

WVashoe County.-- Adult populations indicated ver, slight dana,:ae in 1937,
only one field '-avin- a, menacing :population. B. curcul.ionis cocoons were very
numerous, indicating that the parasite will be effective, as usual, next
season-in minimizin, the production of weevils. Results of the survey in this


county, sampled on November 21-22,


were as follows:


Field No.'

1--
2
3- -
4 - -
5 - -
4--
5--
6
7--
8 --
9 - -
9--
10--
11 - -
12 - -


E. oostica
adults
Numb e r
0.50
.25
0
.25
.50
3.25
1.00
025

.50
1.00
.25


B3. curculionis cocoons
Prcsenit : Viable


4


NTumber
33.00
1.50
1.75
21.50
4.75
69.50
15.75
15.00
3.75
8.75
17.50
23.25


Percent
6.58
0
14.29
0
21.05
3.00
3.17
7.69
40.00
8.57
10.00
0


Average -


0.65


18.42


5.81


*0nl- 100 dissected of total..

Churchill Coun t.- Adult populations indicated no damagIre in 1937, no
fields having, menacing populations. B. curculio.is cocoons were rather n'm-er-
ous and, in view of the small weevil population, the parasite will be effec-
tive next season in p.e-/e.'ting larc-e weevil populations. The following






-41-


table shows the results of the survey inQiXehlll County, sampled on
November 17-19.


Field 1


1 -
2
3-
4
5
6
7
8
9
10 -
11 -
12 -
13 -
14
15 -
16 -
17 -
18 -
19 -
20 -
21 -
22 -
23 -
24
25 -


B. curculionis cocoons


[o_.








- - 4
9



-_ 4
-~ 4



-
_ S
---- -- H- 4
-* --- ---- ,
___ ...__ __.
--



'~ -- --- --- @

--- __. <
t


H. postica
adults
lTumber
0
0
0.75
0
0
.25
0
0
.25
.25
.50
.50
.50
0
0
0
0
0
0
0
.75
0
0
0
0


Average -


: 0.15


8.97


6.02


IIM3RA SYA

Sioux County.-- The infestation in western Nebraskla first attracted
attention in 1934, when slight aLjc'-.-e was reported in Sioux County, and
since that time a few fields have been dmrva-ed annually. In 1936 only one
field was severely dami.,ed. I'-,o additional ones showed heavy feedinTz but,
in general, weevils were scarce throughout the county. Ecological studies
last season revealed the fundamental trends of the weevil population to be
roughly comparable to those existing thro'izhout the older infested areas.
A fall survey of 12 fields was consequently in re to complete the year's
studios. Adult populations indicated virtu-lly no dn?,-,e next season, only
one field -uving r.-ienacinr- numbers. B. curculionis cocoons were scarce and,
in view of the low effectiveness of this p.arasite last season, si..c! hardly
sufficient to be more effective in 1937. The eytrc'.ly cold winter, comz2n
to this area, ma.iy furthLer reduce both parasite and we.vevil populations.


Present
luuiber
5.25
10.00
18.75
12.00
.75
12.50
12.00
13.25
19.50
8.75
9.25
17.75
3.00
.50
3.75
11.75
1.25
17.50
4.75
1.25
3.75
1.00
21.50
4.25
10.25


Viable
Percent
4.76
2.50
1.33
4.17
100.00
4.00
22.92
11.32
0
5.71
16.22
4.23
8.33
0
0
2.13
20.00
8.57
5.26
20.00
0
0
2.33
5.88
4.88




UNIVERSITY OF FLORIDA
1111111i11111111111111111111111111111111111111l11 11I I1 1I111 1111
_42_ 3 1262 09244 6474

I.
The results of the survey in Sioux County, sampled on October 27, are tabu-
lated .below.


Field No.


2
21-- - -

43--- ---
4

6
7
8
9 - - -

10

12 - - -

Average -


_H. -postica
adult s
Number
1.25 .
.75
.50


I




9



*


S0
0
.25
.25,
S 0
.25
0
S 2.00.
.25.


0.46


: B. curculionis cocoons -
Present : Viable
Number Percent
2.50 30.00
.25 0
.25 0
.25 : 0
0
.25 0
.50 50.00
0
.25 0
0
: .50 0
3.50 1 7.18

0.73 : 15.15


OUTLOOK FOR WEEVIL DAMAGE IN 1937


Estimates of probable weevil damage next season are based only on those
fields actually having menacing adult populations this fall; however, there
are fields in each locality that have slightly fewer adults than the number
considered menacing and these fields are in a doubtful class. The damage ex-
pected next season, therefore, may be mpre or less extensive than is intimated
in this estimate, depending on whether the spring is adverse or favorable for
weevil development. Results of the fall survey indicated that widespread,
severe damage next season will be limited to Mesa County, in western Colorado,
where throe-fourths of the fields are menaced. Roughly,' one-fourth of the
total number of fields surveyed are menaced, and moderate damage is expected
in the upper Snake River Valley of eastern Idaho; in Jackson County, south-
western Oregon; in Delta and Montrose Counties, western Colorado; in Douglas
County, western Nevada; and in Box Elder, Salt Lake, Sevier, and Sanpete
Counties, Utah. Slight or negligible damage is expected in the lower Snake
River Valley of western Idaho and eastern Oregon; Eagle Valley, Baker County,
Oreg,; Sioux County, Neb.; and Washoe and Churchill Counties, western Nevada.
With the exception of western Colorado and southwestern Oregon, the parasite
promises to be effective in preventing the production of large weevil popula-
tions in 1937. In western Colorado the parasite is rather scarce and, further-
more, its value is doubtful because of its early spring decline in effective-
ness. In southwestern Oregon the parasite has only recently been introduced
and is not sufficiently abundant to be widely effective as yet, but the results
of the recent fall survey reveal that it is rapidly establishing itself.


III I U