1. Management of Southern Root-Knot Nematode
in Appling County, Georgia
D.S. Curry1and R.C.Kemerait2
1University of Georgia Coop. Ext., Baxley, GA 315191 and 2Dept. of Plant Pathology, University of Georgia, Tifton, GA,
ABSTRACT
31793. RESULTS and DISCUSSION (continued)
Management of the plant-parasitic nematodes is of critical 4. Use of PHY 367 did not result in a decrease of late-season root
importance throughout Georgia and annually costs producers galling nor did it result in decline of late-season nematode
more than $100 million. The southern root-knot nematode populations as compared to PHY 375. PHY 367 out-yielded PHY
(Meloidogyne incognita) is especially important in Appling County 375 by 191 lb/A lint.
where sandy soils and long-term cotton production allow for
damaging populations of this organism to develop quickly. The 5. Use of Telone II resulted in numeric increase in yield and gin turn-
objective of this study was to determine appropriate management out and numeric decline in late-season root damage. Telone II was
strategies for management of M. incognita with the use of a the most important production practice in this study to be of benefit
partially resistant variety (PHY 367B2RF), a seed treatment to the grower.
nematicide (AVICTA Complete Cotton) and Telone II. The
population of M. incognita in the field used in this study was as 6. Efficacy of AVICTA Complete Cotton to manage nematodes in this
much as 6X the economic threshold level for the southern root- A cotton field in Appling County planted to a heavy cover-crop of rye was fumigated study was tied to the area of the field where evaluated. Where
knot nematode in Georgia. Little difference was noted between with Telone II, 4 gal/A, weeks prior to planting. A good stand was established nematode populations were moderate, the treatment appeared
damage to the PHY 367 versus PHY 375. Yield for resistant PHY despite the heavy residue. Fumigation process was difficult because cover crop had appropriate.
not been “killed”.
367 treated with AVICTA was 191 lb/A greater than where PHY
375 was planted. Fumigation with Telone II in conjunction with Figure 1. M. incognita, juveniles/100cc soil at harvest
MATERIALS and METHODS
either variety resulted in a numeric reduction in root-damage and 1. A replicated field trial was established on the Jeff Deen farm in Appling 800 NS
an increase in yield (413 lb/A). SPECIAL NOTE:
County, Georgia in 2011. This field has a history of losses to M. incognita. For Figures 1 and 2 two
600
sets of data are presented
2. The experimental design was a factorial randomized complete block with for PHY 375 + AVICTA
400
and PHY 367 + AVICTA.
3 replications. Treatments included combinations of PHY 367B2RF and Originally the second set
200
PHY375B2RF (seed treated with AVICTA Complete Cotton) with and was to be over-treated
without Telone II (1,3-dichloropropene, 4 gal/A). Fumigation with occurred 0 with VYDATE CLV. As
PHY367+AVICTA PHY375 + AVICTA this did not happen, the
weeks prior to planting. The cotton crop was planted on 7 Jun and plots were simply
PHY367+AVICTA + Telone PHY375 + AVICTA+ Telone
harvested on 15 Nov. duplicates of other
PHY367 +AVICTA PHY375+AVICTA treatments. The data are
presented separately here
3. Vydate CLV, planned as a third treatment to compliment use of AVICTA Figure 2. Galls per gram of root at harvest as results from this study
Complete Cotton, was not applied. Thus, there were two sets of plots clearly document that
treated with AVICTA but not Vydate. Yield was not determined for the 40 efficacy of seed-treatment
nematicides is closely tied
second set of these pots. 30 to the magnitude of
A A
populations of parasitic
20 nematodes in a field.
4. Data collected included soil sampling to determine nematode B B B B
Coincidentally, the second
populations, end-of-season root-damage ratings, and yield (non- 10 set of seed treatments
replicated). was placed in severely
0
infected areas of the field.
A root system damaged by southern root-knot PHY367+AVICTA PHY375 + AVICTA
nematodes (above, at right). In picture at right, PHY367+AVICTA + Telone PHY375 + AVICTA+ Telone
collecting soil samples after harvest to determine
PHY367 +AVICTA PHY375+AVICTA
end-of-season levels of plant parasitic nematodes.
Figure 3. Gin Turn-out as determined by the Figure 4. Lint Yield based upon gin turnouts reported by
1048 Satilla Cotton Gin Satilla Cotton Gin
INTRODUCTION % Lint
1,600
1,501
Yield/lbs Per acre
Appling County lies in the Coastal Plain of southeastern 45%
41%
1,400
1,279
Georgia. Cotton is an important crop for growers in this county 40%
36%
31%
1,200
1,088
and management of plant-parasitic nematodes is especially 35% 1,000
30%
important as soils in the county are typically very sandy. 25%
800
600
Meloidogyne incognita, the southern root-knot nematode, is the 20%
400
15%
most important nematode affecting cotton in this region. 10% 200
Growers have historically used aldicarb, Temik 15G, to manage 5% 0
PHY 375 + Telone + PHY 367 + Avicta PHY 375 + Avicta
both thrips and nematodes; however the loss of Temik 15G 0%
PHY 375 + Telone + Avicta PHY 367 + Avicta PHY 375 + Avicta
Avicta
early in 2011 necessitated additional field trials to determine Data reported in Figures 3 and 4 are based upon combined harvest of all plots of a given
refined opportunities for control of nematodes in Appling County. treatment. Plots for the treatment PHY 367 + AVICTA + Telone II were not harvested due
RESULTS and DISCUSSION to error. Seed-cotton yields for plots treated with Telone II were more than 300 lb/A
1. The field trial at the Jeff Deen farm is pictured in photos above just greater than were yields in plots that were not fumigated. However, based upon reported
The objective of this study was to compare the performance of a prior to harvest. Plots fumigated with Telone II are obvious; however it is gin turn-out, reported lint differences are much greater than anticipated. ALSO: Data for
cotton variety with known partial-resistance to the root-knot the AVICTA-ONLY treatments does not include the second set of plots where damage
not possible to differentiate plots planted to PHY 367B2RF versus PHY from nematodes was most severe.
nematode (PHY 367B2RF) treated with AVICTA Complete 375B2RF.
Cotton to a popular variety without resistance (PHY 375B2RF),
also treated with AVICTA Complete Cotton. Additionally plots 2. From nematode samples collected after harvest (Figure 1) it is clear Special Thanks to: Jeff
planted to each variety as above and fumigated with Telone II (4 that the populations of root-knot nematodes in the field far exceed the Deen (right), Greg Black,
gal/A), were compared to non-fumigated plots. It was hoped that economic threshold established for Georgia (100 juveniles/100cc soil). Lamar Turner, Satilla Cotton
the results from this study would give growers in eastern Despite use of a resistant variety (PHY 367B2RF), high counts were Gin, Dow AgroSciences, and
Georgia better idea strategies to integrate nematode resistance found in all treatments. Phytogen Cotton Seed.
and nematicides into their cotton production practices.
3. Plots originally to be treated with Vydate CLV following emergence
were used as a second set of AVICTA Complete Cotton treatments. This
proved fortuitous as areas planted were more affected by nematodes
than the first set.