? 9L/$. Evaluation of candidate nematicide MON37449
for the management of Meloidogyne incognita on Cotton
Robert A. Kinloch nARSTO SCtMCE U118rW
University of Florida MAR 2 9 199
West Florida Research and Education Center
Research Report 1999-,
A candidate nematicide, MON37449 [Monsanto Company], was evaluated for its efficacy for
managing the root-knot nematode, Meloidogyne incognita, in a field infestation on the Davis'
Brothers farm in Santa Rosa County, Florida, during 1998.
The experimental site was a sandy loam soil (82% sand, 10% silt, 8% clay) naturally infested
with the nematode. Prior to establishing the plots, the area was disc-cultivated and standard
applications of fertilizer and herbicide were applied (Sprenkel, 1996). The site was demarcated
into 36 two-row plots, 7.2 m long on 0.9 m centers. Each plot was sampled to determine its
nematode soil population density on 1 June 1998 by removing eight soil cores (2.54 cm wide X
20 cm deep), mixing the cores, and processing a 100 cm3 sub-sample via sugar centrifugation
(Jenkins, 1964). Six treatments, including an non-treated check, were replicated X6 on a Latin
square design. The treatments were; Telone II [DowAgrosciences] at 42 liters/ha applied via a
single chisel to a depth of 34 cm beneath the row on 1 June following nematode sampling;
MON37449 at 0.28, 0.6, and 1.10 kg active ingredient/ha applied to a 7-cm-wide furrow-band on
4 June; Temik 15G [Rhone-Poulenc] at 0.8 kg active ingredient/ha applied to a 7-cm-wide
furrow-band on 4 June. All plots, with the exception of those treated with Temik, received a
treatment of 0.8 kg active ingredient/ha of phorate for thrips management at the planting of Delta
Pine 485 BR cotton on 4 June. The plots were harvested on 29 October and post-harvest
nematode soil population levels were re-sampled for each plot on 3 November. All data were
subject to Latin Square analyses.
There were no significant (P < 0.05) differences in the pre-treatment soil infestation levels of
M. incognita second-stage infective juveniles (J2) among the plots assigned to the different
treatments (Table 1). These averaged 43/100 cm3 soil. The cotton crop was subject to
considerable drought stress through much of the early season(Table 2). Undoubtably, this
contributed to low yields. Telone II significantly out-yielded the non-treated check and all other
treatments. None of the latter were significantly different from the non-treated check. There was a
weak trend (r = -.35, P < 0.2) to decreasing yield with increasing dosage rate with MON37449.
This may indicate some phytotoxic effect. Similarly, there was a weak trend (r = -.29, P < 0.3) to
decrease the post-harvest J2 soil infestation level with an increase in rate of this candidate
nematicide. All post-harvest J2 levels were lower with the candidate nematicide than were those
following treatment with Temik. Telone significantly reduced the post-harvest J2 population
density below the non-treated check and all other treatments.
Jenkins, W. R. 1964. A rapid centrifugal-flotation technique for separating nematodes from soil.
Plant Disease Reporter 48:692.
Sprenkel, R. K. 1996. 1996 Cotton production guidelines. University of Florida Cooperative
Extension Service publication SS-AGR-62. Gainesville, FL.
Table 1. Response ofMeloidogyne incognita second-stage infective juveniles (J2) and Delta
Pine 485 BR cotton yield to soil treatment with selected nematicides.
Treatment J2/100 cm3 soil lint kg/ha J2/100 cm3 soil
01 Jun 29 Oct 03 Nov
MON37449 15G 37a 469 c 168 c
1.1 kg a.i./ha
MON37449 15G 32 a 521 bc 245 bc
0.6 kg a.i./ha
MON37449 15G 47 a 561 b 257 bc
0.28 kg a.i./ha
Temik 15G 33 a 549 b 360 a
0.8 kg a.i./ha
Telone II 18 a 799 a 68 d
Check 37 a 487 bc 308 ab
Data are the averages of six replications.
Averages followed by a similar letter within a column are not significantly (P < 0.05) different
according to Duncan's multiple range test.
Table 2. Weekly rainfall (cm) recorded at the West Florida Research and Education Center
from 1 June to 9 August.
Week 1 2 3 4 5 6 7 8 9 10
1998 1.50 0 0 0.74 1.73 2.49 4.06 2.90 3.20 0.51
1993-97 average 5.20 2.00 5.50 4.70 1.22 7.32 4.95 4.32 5.33 7.80