Group Title: CFREC-Apopka research report - Central Florida Research and Education Center-Apopka ; RH-88-5
Title: Efficacy of Aliette 80WP in controlling Pythium root rot of Begonia and Phytophthora stem rot of Aphelandra
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Permanent Link: http://ufdc.ufl.edu/UF00065966/00001
 Material Information
Title: Efficacy of Aliette 80WP in controlling Pythium root rot of Begonia and Phytophthora stem rot of Aphelandra
Series Title: CFREC-Apopka research report
Physical Description: 2 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Central Florida Research and Education Center--Apopka
Publisher: University of Florida, IFAS, Central Florida Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1988
 Subjects
Subject: Begonias -- Diseases and pests -- Control -- Florida   ( lcsh )
Aphelandra -- Diseases and pests -- Control -- Florida   ( lcsh )
Fungal diseases of plants -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 2).
Statement of Responsibility: A.R. Chase.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065966
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70949989

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-5 Efficacy of Aliette 80WP in Controlling Pythium Root Rot
Central Science of Begonia and Phytophthora stem rot of Aphelandra
Library A. R. Chase1

G: n Ia 1s University of Florida, IFAS
Central Florida Research and Education Center Apopka
Un!fsity of FLri CFREC-Apopka Research Report, RH-88-5
University of Fk' rs rir
-- Pythium and Phytophthora spp. cause a number of serious diseases
common to foliage plants in Florida. Fungicides frequently used to control
many of these diseases include those containing metalaxyl (Subdue 2E),
etridiazole (Truban and Terrazole formulations) and fosetyl aluminum
(Aliette 80WP). All of these compounds are used as drenches with fosetyl
aluminum also used as a foliar spray. The two experiments reported here
were conducted as part of the specialty crops project funded by IR-4.
Efficacy of fosetyl aluminum applied as a spray or drench for control of
Pythium root rot of Begonia or Phytophthora stem rot of Aphelandra was
determined.
Begonia 'Mini Angelwings' unrooted cuttings were rooted in
steam-treated potting medium (Canadian peat-pine bark 1-1). Fungicide
treatments were various rates of Aliette 80WP applied as either a spray or
a drench and Subdue 2E was applied at the recommended drench rate and
served as a standard control. Fungicides were applied prior to inoculating
plants with Pythium splendens. Drench treatments were applied at the rate
of approximately 1 pint/ftt potting medium surface area and sprays to the
point of runoff. Treatments were applied a second time approximately 6
weeks after the initial application. Plant height and fresh weight of tops
were determined about 6 weeks after the second application (12 weeks after
initiation).
Best plant growth occurred in the noninoculated control and Subdue 2E
treatments (Table 1). In addition, the low rate of the Aliette 80WP spray
and the Aliette 80WP drench both gave good growth responses. Higher rates
appeared to cause growth reductions possibly due to a phytotoxic reaction
by this plant.
The second trial was conducted using rooted cuttings of Aphelandra
squarrosa. The same potting medium was used as for the begonia test. In
this case, the treatments included higher rates of Aliette 80WP for the
sprays, the same rates for the drenches but no standard control was
included. Treatments were applied prior to inoculation with Phytophthora
parasitica and again one month later. In this case the experiment was
completed only 8 weeks after initiation due to rapid plant growth and death
of 90% of the inoculated controls within the first 6 weeks. Aliette 80WP
gave excellent control of Phytophthora stem rot of Aphelandra since none of
the treated plants died compared to 90% of the inoculated controls. Plants
height, number of leaves, and fresh weights of roots and tops were all as
good as or better than the noninoculated control and plants sprayed with
the 20 Ib rate of Aliette 80WP were exceptionally vigorous (Table 2).
However, this rate (20 lb/100 gal) is well in excess of labeled rates for

1Associate Professor of Plant Pathology, Central Florida Research and
Am Education Center Apopka, 2807 Binion Road, Apopka, FL 32703.









this fungicide and should not be used.
Although Aliette 80WP may have caused phytotoxicity on Begonia:'Mini
Angelwings' it was safe on Aphelandra squarrosa even when used at twice the
highest rate used on the Begonias. Aliette provided excellent control of
Phytophthora stem rot but gave a lesser degree of control of Pythium root
rot. Similar differences in efficacy dependent upon the host, have been
noted for this compound in the past (1). Always use the appropriate rates
of any chemical on labeled plants.
Reference
1. Chase, A. R., D. D. Brunk and B. L. Tepper. 1985. Fosetyl aluminum
fungicide for controlling Pythium root rot of foliage plants. Proc.
Fl. State Hort. Soc. 98:119-122.

Table 1. Effect of Aliette 80WP sprays or drenches on severity of growth
reduction on Begonia 'Mini Angelwings' infected with Pythium splendens.

Plant height Fresh weight
Treatment rate/100 gal (inches) tops (g)

Noninoculated -12.0 cx 34.9 b
Inoculated 8.4 ab 21.4 ab
Aliette 80WP spray 2.5 lb 10.0 abc 24.9 ab
Aliette 80WP spray 5.0 lb 8.9 ab 19.6 a
Aliette 80WP spray 10.0 lb 7.5 a 15.3 a
Aliette 80WP drench 2.0 lb 10.1 abc 22.0 ab
Aliette 80WP drench 4.0 Ib 7.6 a 11.4 a
Subdue 2E drench 2.5 oz 11.0 bc 34.6 b

xNumbers in the same column followed by the same letter were not
significantly different at the 5% level (Duncan's New Multiple Range
Test).

Table 2. Effect of Aliette 80WP sprays or drenches on severity of
Phytophthora stem rot of Aphelandra caused by Phytophthora parasitica.

Plant Fresh Fresh
height Number weight of weight of
Treatment rate/100 gal (inches) leaves root (g) tops (g)

Noninoculated 5.1 bx 21.3 b 25.5 b 38.9 b
Inoculated 0.5 a 2.6 a 2.5 a 4.4 a
Aliette 80WP spray 5.0 lb 5.4 bc 23.0 bc 29.2 bc 43.1 bc
Aliette 80WP spray 10.0 lb 5.8 bc 28.7 de 29.4 bc 47.6 c
Aliette 80WP spray 20.0 Ib 6.2 c 30.0 e 28.4 bc 49.3 c
Aliette 80WP drench 2.0 lb 5.3 b 24.2 bcd 32.2 c 43.4 bc
Aliette 80WP drench 4.0 lb 5.6 bc 26.7 cde 29.7 bc 48.3 c

XNumbers in the same column followed by the same letter were not
significantly different at the 5% level (Duncan's New Multiple Range
Test).


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