An improved trap for collecting aphids

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Material Information

Title:
An improved trap for collecting aphids
Physical Description:
Book
Creator:
Davis, W. E
Landis, B. J ( Birely J. ), 1904-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Bureau of Entomology and Plant Quarantine ( Washington, D.C )
Publication Date:

Record Information

Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030362636
oclc - 783517168
System ID:
AA00023185:00001

Full Text
STATE L

December 1949 ET-278

United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine



AN IMPROVED TRAP FOR COLLECTING APHIDS

By E. W. Davis and B. J. Landis,
Division of Truck Crop and Garden Insect Investigations I/


The number of aphids in flight along an air front may be estimated
from area samples taken as the insects pass a number of points. Aphids
fly when the air is still or when the velocity of the wind is less than 4
miles per hour. Without a wind the flight is at random and the direction
of the air front is unimportant. However, since aphids are carried by a
wind, the most populous sampling area is in a plane perpendicular to the
direction of the wind.

Shands, Simpson, and Lathrop (1) developed an aphid-collecting trap
which is simple to operate and reasonably efficient in catching and re-
taining flying aphids. The improved trap described herein utilizes the
same collecting and retaining principles of the Shands trap, but it is
easier to make, responds more readily to changes in wind direction, and
the solid construction of two of the sides causes a greater deflection of
the air-borne aphids into the collection cap. In 1948 a Shands trap and
one of the improved traps were operated side by side at Yakima, Wash.,
for 38 days. A total of 518 aphids were caught in the old trap and 1,264
in the improved trap. On each of 34 days more aphids were taken in the
improved trap than in the old trap.

Description

The improved trap (fig. 1) has the same general upswing and diminish-
ing shape from front to back as a curved horn. When in an operating
position the large opening, or mouth, is vertical and the small opening
is on a horizontal plane. Because of the curved shape of the trap the
small opening is 5 inches above and 15 inches to the rear of the large
opening. The openings are not shown in figure 1, but one side of the
large opening may be seen at the extreme right of A and the small open-
ing is in the block at the top of the trap.


I/ In cooperation with the Washington Agricultural Experiment Station.





-2-


The 1/4-inch thick, marine-plywood sides of the trap are 20 inches
wide at the large end, and diminish in width to 2 1/2 inches at the small
end. At the large end the sides are fastened together at top and bottom
by 1- and 2-inch boards 20 inches long (not shown), thus forming a rec-
tangular mouth of the trap 20 by 18 1/2 inches. One side of this mouth is
at the extreme right of A. At the small end the sides are held together
with a piece of plywood 3/4 inch thick and 4 1/2 inches square. In this
plywood block is a 2-inch hole, over which is fastened an inverted metal
screw band from a two-piece fruit-jar cap. This screw band holds a
cotton scrim "baker's cap," as described by Shands (1), which keeps the
aphids in the trap. The two sides of the trap not covered with plywood
are enclosed with pieces of cotton scrim, drawn tight, tacked, and glued
to the outside of the plywood sides, as is indicated by the gray stippled
areas on the figure. No folds of cloth are present in which aphids might
become trapped.

A frame of 1- by 2-inch boards supports the trap, and to this frame
the wind vane is attached. The two vertical supports are 18 inches long.
and one is bolted to each of the plywood sides of the trap 5 inches from
the large opening. These supports extend 6 inches below the trap and
are joined by two cross pieces placed 4 inches apart, the uppermost one
touching the base of the trap. A 1/4- by 9-inch headless, spring-steel
bolt extends through the center of each cross piece and is fastened by a
nut above and below the top cross piece. The free end of the steel bolt
is inserted into the fence-post assembly (B), upon which the trap rests.

A hole 3/8 inch in diameter and 4 1/2 inches deep is bored into the
fence post from the top. A short length of copper tubing, closed at the
bottom and containing a small steel ball bearing, is driven to the bottom
of the hole. A roller-skate .wheel is fastened to the top of the fence post
directly over the hole. The skate wheel, or upper bearing, greatly in-
creases the sensitivity of the trap and causes it to head into the slightest
breeze.

The wind vane is made of 1- by 2-inch board 24 inches long, with a
tin fin, 7 1/2 inches wide and 19 inches long, fastened at one end and
bolted at the other end to the lower cross piece at a 900 angle. The wind
vane is fastened slightly to one side of the long steel bolt.

Literature Cited

(1) Shands, W. A., Simpson, G. W., and Lathrop.
1942. An aphid trap. U. S. Bur. Ent. and Plant Quar. ET-196,
6 pp., illus. /Processed3






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Figure l.--An improved trap for collecting alate aphids: A, Three-
quarters view of back and one side of the trap; B, fence-post assembly
consisting of roller-skate wheel bearing, single ball bearing, and copper
tubing.




UNIVERSITY OF FLORIDA

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