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Copyright 2005, Board of Trustees, University
of Florida

Marston Scienrn

APR 1 5 1993

University of Florida

EFFICACY OF AN EXPERIMENTAL CHEMICAL,
FOSTHIAZATE, FOR MANAGEMENT OF
THE JAVANESE ROOT-KNOT NEMATODE
IN TOBACCO 1992

IFAS NFREC Quincy Research Report 92-13

Jimmy R. Rich
IFAS NFREC
Route 3 Box 4370
Quincy, Florida 32351

INTRODUCTION

The nematology program at the NFREC, Quincy, conducts research

to reduce nematode damage in crops that are important to north

Florida. Nematicide trials are a large part of this effort. The

trial reported herein was conducted to evaluate the efficacy of a

new chemical from ISK Biotech, fosthiazate, for management of the

Javanese root-knot nematode in flue-cured tobacco.

MATERIALS AND METHODS

The field trial was conducted at the IFAS Suwannee Valley

Agricultural Research and Education Center, Live Oak, in a Lakeland

fine sand soil (93% sand, 4% silt, and 3% clay) infested with the

Javanese root-knot nematode, Meliodogyne javanica. The field was

previously cropped to soybeans. In mid-March, the field was turned

with a moldboard plow to 10" deep and leveled by double discing.

On March 24, 1,3-D was applied with a single chisel in-row to a

depth of 12". Fosthiazate and fenamiphos were applied on April 3

as broadcast applications. Application of these materials was made

in 20 gal/A of water with a tractor-mounted CO2 sprayer containing

8004 teejet nozzles. The materials were double-disced to

incorporate to a depth of 3-5". All plots were bedded and "NK 326"

tobacco was transplanted 18" apart in-row on April 3. The trial

was arranged in a randomized complete block design containing six

replicates. Plots were 2 rows, each 44" wide, and 25' long. The

crop was maintained under irrigation during the growing season.

Tobacco was observed weekly for phytotoxicity. Root gall

ratings were conducted on two plants in each plot 121 days after

transplanting, using a gall scoring system of 0-4. Tobacco was

harvested 4 times, green weights recorded and converted to cured

weight (x 0.15). Tobacco yield was calculated to represent lbs./A

yield.

RESULTS

The 1,3-D and fenamiphos treatments significantly improved

tobacco yields as compared to the control (Table 1). No

significant differences in yield were found among the fosthiazate

treatments and any of the other chemical treatments or the control.

As rates of fosthiazate increased to 3.75 ai/A, tobacco yield

similarly and numerically increased among these treatments

Root-galling was significantly reduced by the two highest

rates of fosthiazate, and the 1,3-D and fenamiphos treatments

(Table 1). Lower root gall ratings were generally apparent as

rates of fosthiazate increased. No phytotoxicity was observed in

any of the treatments.

DISCUSSION

Tobacco yields were relatively low due to excessive moisture

resulting in leaching of applied fertilizer. Also, initial

populations of M. javanica were high with densities of 274/100 cm3

at planting. These factors may have contributed to the less than

optimum performance of the lower rates of the non-fumigant

nematicide, fosthiazate. These data suggest, however, that the

lower rates of fosthiazate (1.875 and 2.813 ai/A) did not provide

adequate control of M. javanica. Thus, it is suggested that rates

of 3.75 ai/A or higher should be tested in the future.

Table 1. Influence of nematicides on root gall index and tobacco
yield in a field infested with Meloidogyne javanica,
1992.

Rate/ Yield Root
Material Acre' lbs./A Galling2

1,3-D 6.000 gal. 2537 a 1.00 bc

fenamiphos 6.000 lbs. a.i. 2450 a 0.42 c

fosthiazate 3.750 lbs. a.i. 2253 ab 0.92 bc

fosthiazate 5.625 lbs. a.i. 2243 ab 1.09 bc

fosthiazate 2.813 lbs. a.i. 2011 ab 1.92 abc

fosthiazate 1.875 lbs. a.i. 1941 ab 2.25 ab

control -- 1578 b 3.25 a

S1,3-D (Telone II) was injected in-row with a single chisel; the
fosthiazate and fenamiphos were broadcast and double-disc
incorporated to 3-5" deep.

2 Root gall index ratings were based on a 0 4 scale with 0 = no
galling and 4 = 76% or greater of the root system galled.