Suggestions concerning the use of DDT dusts on potatoes in eastern Washington


Material Information

Suggestions concerning the use of DDT dusts on potatoes in eastern Washington
Physical Description:
2 p. : ; 27 cm.
Landis, B. J ( Birely J. ), 1904-
Getzendaner, C. W
United States -- Bureau of Entomology and Plant Quarantine
United States Department of Agriculture, Agricultural Research Administration, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:


Subjects / Keywords:
Potatoes -- Diseases and pests -- Control -- Washington (State)   ( lcsh )
DDT (Insecticide)   ( lcsh )
Spraying and dusting in agriculture   ( lcsh )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Additional Physical Form:
Also available in electronic format.
Statement of Responsibility:
by B.J. Landis and C.W. Getzendaner.
General Note:
Caption title.
General Note:
General Note:
"May 1946."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030291676
oclc - 779962527
System ID:

Full Text
May 19146 E-689

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


By B. J. alndis and C. W. Getzendaner, Division $
Truck Crop and Garden Insect Investigation'

Potato growers in parts of the Pacific Northwest infested with
the tuber flea beetle (Epitrix tuberie Gentner) and the western pota-
to flea beetle (Z. suborinita (Lee'.)) find. it necessary to apply inr-
secticides periodically for the control of these insects. For the
past several years large numbers of the green peach aphid (Myzus
persica. (Sule.)) and smaller numbers of the potato aphid (Macrosiphum
solanifolii (Ash.a)) have infested potatoes, but few growers have ap-
plied insecticides for control of these insects. The calcium arsen-
ate or crzyolite dusts applied to control flea beetles on potatoes do
not control the aphids. and this practice even may encourage the de-
velopment of abnormally large numbers of aphids*

Daage to potato tubers caused by larvae of potato flea beetles
can be identified readily during the growing season and is recognized
as a grade defect at harvest* The devitalizing effect of aphids suck-
ing the Juices from potato foliage causes a reduction of yield but
does not cause grade defects in marketable-size potatoes. The green
peach aphid and the potato aphid are of greatest importance as car-
riern of potato virus diseases from diseased to healthy plants. Cer-
tain virus diseases greatly reduce yields of potatoes and also cause
an internal deterioration of the tubers, which may worsen during
periods of storage.

In 1945 winged green peach aphids were first observed on small
potato plants on Nay 5 and were present in most potato fields by kMay
15*. The aphids occur on the under side of the lower leaves of potato
plants during the first part of the growing season and may escape
caual observation because of their sa3l size and pale green color,
ftey gradually increase in number during the spring months and become
most abundant at about the time the plants bloom. Numbers of aphids
sufficient to produce a wet, shiny glaze on the leaves nmay be pro-
duced from June 15 to 30 on early potatoes, and from July 25 to August
20 on late potatoes. Varying numbers of winged aphids develop on po-
tato plants throughout the season, and these may fly into other fields
of potatoes.

_/ In cooperation with the Washington Agricultural Experiment


3 1262 09238 7488

Experimental work with DDT dusts applied periodically to foliage
in fields of potatoes during the last 2 years has shown that aphids
and flea beetles aay be kept at relatively low numbers throughout the
period of treatment. In fields so treated until the Tines matted the
rowse, the amount of flea beetle injury at harvest was no greater,
often less, than that after similar applications of either calcium ar-
senate or cryolite dust.

Observations as to the effectiveness of single applications of MDT
dusts in several fields of potatoes heavily infested with the green
peach aphid shoved that, although very few aphids were killed during
the first 2 days following treatment, their population decreased 92 to
97 percent within the first week. Under conditions in the Takima Val-
ley DDT dusts gradually lose their effectiveness beginning about 10
days after they have been applied to foliage. In this respect DM
dusts are not materially different from either calcium arsenate or
cryolite dusts, and therefore should be applied repeatedly for best
results. The frequency with which ground-type dusters my be used. In
applying insecticides depends, in many localities, upon the number and
duration of periodic irrigations of the crop. Because of the gradual
reduction of effectiveness of the DDT dusts following application, it
is desirable to adjust the irrigation practice so that dusts my be
applied at short intervals.

Dusts containing 5 percent of DDT are preferable to those of lover
concentration where flea beetles and aphids are present. The most sat-
isfactory control was obtained where the first application was made soon
after the potato plants came through the ground and additional applicap-
tions were made at 10-day intervals until the vines matted the rows.
The first application may be made at the rate of 15 pounds of the 5-
percent DDT dust per acre and the dosage should be increased gradually
to 35 pounds for the last dusting. Ground dusting machines should have
an 8- to 10-foot canvas drag to prevent excessive drift of the dust*

Although experiments with DIDr for the control of flea beetles and
aphids on potatoes have not been conducted in western Washington, there
is no reason to believe that the material will not be effective in that