Group Title: Press bulletin
Title: Winter treatment for whitefly
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 Material Information
Title: Winter treatment for whitefly
Series Title: Press bulletin
Physical Description: 2 leaves : ; 21 cm.
Language: English
Creator: Berger, E. W ( Edward William ), b. 1869
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville
Publication Date: 1910
Subject: Citrus whitefly -- Control -- Florida   ( lcsh )
Citrus -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: by E.W. Berger.
General Note: Caption title.
General Note: "February 19, 1910."
 Record Information
Bibliographic ID: UF00090366
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 78615131

Full Text


Florida Agricullural Experiment. Station

By E. W. Berger
There is still time to carry on winter treatment against the whitefly
because it is in its larval and pupal stages, and there are no adults to fly
away, or eggs that are difficult to kill. Spring and fall spraying have their
uses, and the fungus diseases have been found efficient during the periods of
spring and summer rains. The problem is: What can be done during the
rest of the winter?
Methods of Treatment
There are two methods of winter treatment-fumigation, and spraying.
Where fumigation can be employed, it is to be preferred. Those who have
carried on extensive fumigation experiments claim that it is less injurious
to the tree than spraying with insecticides. Quicker and better results
can undoubtedly be obtained with it, especially on the larger trees where
it is difficult to wet all the leaves by spraying. For small and medium-
sized trees spraying can, however, be made just about as effective.
That winter spraying against the whitefly can be made effective has
been demonstrated. The solutions must of course be used much stronger
in winter than in summer. The writer has in mind a locality in Florida
in which the growers organized a protective league, assessed each grower
one cent per year for each tree he owned, and have kept the pest from
spreading during the past two years. In this locality the whitefly had just
become started in two or three groves, and the results of spraying have
been so successful that but few if any more whitefly larvae could be found
last fall than three years ago. These spraying operations appear to be
the most effective on record with the whitefly. The insecticide used was
a proprietary miscible oil. Another grower states that he has succeeded
in keeping the whitefly confined to a few trees in one corner of the grove
for four or five years by thorough spraying with another miscible oil. For
winter spraying, whale-oil soap should not be used weaker than 1 pound
to 4 gallons of water.

February 19, 1910

Localities Just Becoming Infested
Winter treatment should not be omitted in any locality in which the
whitefly is just coming in and is confined to a limited area. Under such circum-
stances there is too much at'stake to delay. .Co-operation should be started
in the form of a protective league. All the groves in such a locality are
threatened, and no grower can afford to omit paying his share towards
keeping the pest confined within its present limits as long as possible. It
pays better to help fight the pest in another man's grove than to have it
in your own. Work should not be postponed with the thought in mind
that something can still be done in the summer, since by so doing the
whitefly is given another chance to spread during its swarming period in
April or May.
Badly Infested Localities.
Where a locality is completely and heavily infested, the trees should
be treated now in order to give them a better chance to set fruit in the
spring. If co-operation can be effected, it is possible to do the work so
thoroughly that no further treatment will be necessary before next fall or
winter. If co-operation for an entire locality is impracticable, it may be
possible to effect co-operation on the part of the owners of localized groups
of groves. Where no co-operation whatever is possible, each grower should
treat his own trees. In this instance spraying should be the method of
winter treatment. It would be inadvisable to go to the expense of fumiga-
tion where the grove is not isolated, but spraying should certainly be done.
Later in April or May, when the grove has become reinfested from the
groves of negligent neighbors, it should be sprayed again. There is a time
in April or May when the whitefly larvae are young and easily destroyed
by whale-oil soap (1 pound to 6 gallons of water) or by any other good
insecticide sufficiently diluted so as not to injure the leaves or young fruit.
This period comes about two weeks after the spring brood of adults has
disappeared from the wing. After that, during the period of summer rains,
if conditions are at all favorable for fungus growth (plenty of moisture,
and good condition of trees) the fungus diseases of the whitefly should be
introduced. Finally, if necessary, the trees should be sprayed again in Oc-
tober or November; in which case, treatment during next winter will not
be necessary.

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