| Material Information
||Rates of Chlor-O-Pic to manage the Javanese root-knot nematode in Florida flue-cured tobacco, 1996
||NFREC research report
||3 leaves : ; 28 cm.
||Rich, J. R ( Jimmy Ray ), 1950-
Whitty, E. B
North Florida Research and Education Center (Quincy, Fla.)
||North Florida Research and Education Center
||Place of Publication:
||Tobacco -- Diseases and pests -- Control -- Florida ( lcsh )
Nematode diseases of plants -- Control -- Florida ( lcsh )
Pesticides -- Application -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )
||Statement of Responsibility:
||Jimmy R. Rich and Elmo B. Whitty.
||Research report (North Florida Research and Education Center (Quincy, Fla.)) ;
| Record Information
||University of Florida
||All rights reserved by the source institution and holding location.
||oclc - 85762787
f 6 0#k-,
RATES OF CHLOR-O-PIC TO MANAGE THE
JAVANESE ROOT-KNOT NEMATODE
IN FLORIDA FLUE-CURED TOBACCO, 1996
NFREC Research Report 97: 4
Jimmy R. Rich
University of Florida
Rt. 3, Box 4370
Quincy, FL 32351
Elmo B. Whitty
University of Florida
304 Newell Hall
Gainesville, FL 32611
JUL 21 1997
University of Florida
Chlor-O-Pic Tobacco Nematicide Test 1996
The trial reported herein was conducted to determine the efficacy of three rates of
Chlor-O-Pic to manage the Javanese root-knot nematode in flue-cured tobacco.
Materials and Methods
A field trial was conducted on a fine sand soil (93% sand, 4%clay, 3% silt) infested with
the Javanese root-knot nematode (Meloidogyne javanica). The test site was at the University
of Florida Green Acres farm in Alachua County, and it was previously in bahiagrass in 1994
and 1995. Soil was prepared by moldboard plowing and double-discing. Fumigant treatments
of Telone C-35 and Chlor-O-Pic were applied on March 26, 1996, by single chisel injection to
10" deep in the row. All plots, including controls, were bedded immediately after treatment.
Tobacco cv. NK 371 was transplanted on April 13 and placed 18" apart in the 48" wide rows.
Plots were two rows wide x 30' long, and treatments were placed in a randomized complete
block design with five replications. Tobacco was grown according to standard cultural
practices and irrigated as required. Early season observations were made to detect any
phytotoxicity, and tobacco was harvested four times, cured and weighed. At final harvest on
August 20, five soil cores (1" diam.) were taken to 12" deep in each plot and composite. A
100 cm3 soil subsample from individual plots was processed by a centrifugation-flotation
technique and second-stage juveniles counted. Root-galling was rated from four plants in
each plot on a 0-10 scale where 0 = 0 root galling and 10 = 100% of the root system galled.
Results and Discussion
Early season phytotoxicity was observed in the Telone C-35 and Chlor-O-Pic
treatments. Plants in 1-2 plots of each treatment were stunted and showed slight chlorosis.
Plant symptoms were related to areas where soil contained highest clay content. Tobacco was
transplanted 18 days after treatment but apparently a longer time interval for fumigant
dissipation was needed in these areas. Plants, however, recovered in two three weeks, and
no effects on yield were apparent.
Tobacco yield differences were not found among chemical treatments or treatments and
the control. All treatments significantly reduced root gall ratings compared to the control.
Low root gall ratings and lack of yield differences reflect low nematode population
development and little damage to the tobacco crop. This was probably due to low initial
nematode populations (4 juveniles/100 cm3 soil) resulting from the use of bahiagrass rotation.
To differentiate treatment efficacy, the test will need to be conducted under conditions of
higher initial nematode populations.
Table 1. Effect of Chlor-O-Pic rates on yield and root galling in a Florida tobacco test, 1996.
Treatment Rate in Yield Galling2
gals./A' Ibs./A Index
Telone C-35 9.0 3064 0.27 a3
Chlor-O-Pic 9.0 3019 0.77 a
Chlor-O-Pic 3.0 2949 0.76 a
Chlor-O-Pic 6.0 2916 0.80 a
Control -- 2903 2.00 b
'Fumigants were injected in the row with a single chisel to 10" deep.
2Root galling was rated on a 0-10 scale with 0 = 0 galling and 10 = 100% of the root system galled.
'Column means followed by the same letter are not significantly different (P < 0.05) according to Duncan's multiple range test.