1. Yield Response and Cotton Root Knot Control with Seed Treatment and Granular Nematicides on Corn
A.K. Hagan and H. L. Campbell
Dept. of Entomology and Plant Pathology, Auburn University, AL
INTRODUCTION
Corn (Zea mays L.) is a host M. incognita race 3 (2) and race 4 (8), but not race 1 or 2 of either M. arenaria or M. incognita (6). Where cotton is produced in the U.S., M. incognita race 3 is the dominant Meloidogyne spp. (2). Bowen et al. (1) estimated that yield losses to cotton root knot nematode (RKN) at 30% of anticipated yield. Commercial corn hybrids are good hosts for RKN (2,4). Limited information is available concerning the impact of nematicides on RKN control and yields of corn. Yield gains in RKN-infested fields of up to 30 bu/A have been obtained in Alabama with the Counter 15G (5) and Avicta Duo Corn (7). Guilhabert-Goya (3) reported a mean yield gain of 4 to 5 bu/A with Poncho VOTiVO on corn. The objective of these studies was to compare the effectiveness of Counter 15G with Poncho VOTIVO and Avicta Duo Corn nematicide seed treatments (NST) and corresponding Cruiser 5FS and Poncho insecticide seed treatments (IST) for the management of RKN and assess their impact on yield.
Figure 1. Growth response of corn when treated with A) Avicta Duo Corn NST + Counter 20G GN compared with B) Avicta Duo Corn alone and C) Poncho VOTiVO NST + Counter 20G GN compared with D) Poncho VOTiVO NST alone.
METHODS
Studies were conducted at the Plant Breeding Unit (PBU) and Brewton Agricultural Unit (BARU) in 2012, 2013, and Only data from the PBU location is presented. Maxim Quattro fungicide seed treatment was applied at 15.8 ml/80,000 seed. The experimental design was a factorial arranged in a split split-plot with year as the whole plot, seed treatments Cruiser 5FS (0.5 mg a.i. thiamethoxam/80,000 seed), Avicta Duo Corn (0.22 mg a.i. abamectin mg a.i. thiamethoxam/80,000 seed), Poncho (0.5 mg a.i. clothianidin/80,000 seed), and Poncho VOTiVO (0.5 mg a.i. clothianidin µg B. firmus I-1582/80,000 seed) as the split plot and the granular nematicide Counter 20G (terbufos) applied in-furrow at-planting at 1.46 kg a.i./ha or non-treated control as the split split-plot treatments. Individual experimental units consisted of two 7.6 m rows on 0.76 m centers in six replications. Yields are reported at 15.5% moisture. From the center two yield rows, initial (Pinitial) soil samples for a nematode assay were collected 30 days after planting and at harvest (Pfinal). For each sampling period, the reproduction ratio was calculated by dividing Pfinal/Pinitial juvenile counts. Soil samples for a nematode assay were processed using the sugar flotation method. Analyses of interactions were done using the PROC GLIMMIX procedure in SAS v with ddfm=satterthwaite option with year, seed treatment, and granular nematicide as fixed effects and year replication-year, replication-seed treatment (year), and replication, seed treatment-granular nematicide (year) as random effects (SAS Institute Inc. 2013). Statistical analysis were done on rank transformations data to normalize variances, which were back transformed for presentation. Means were separated using Fisher’s protected LSD test (P<0.05) unless otherwise indicated.
Table 1. F values for generalized linear models for effects of year, seed treatment, and granular nematicide on stand count, root-knot reproduction, seedling weight, and yield in 2012, 2013, and 2014 at the PBU. B
Source of variation
(F values)
Plant
populationZ
RKN
reproduction
rate
Dry
stalk
weighty
Fresh
seedling weightZ
Yield
Year
7.90** x
13.38***
---
177.72***
200.01***
Seed Treatment
2.25^
0.31
0.28
3.42*
3.38*
Year x Seed Treatment
0.19
0.56
3.07*
0.38
Granular Nematicide
12.73***
3.16^
0.06
27.05***
33.52***
Year x Granular Nematicide
1.98
2.32
3.31^
0.03
Seed Treatment x Granular Nematicide
0.79
0.12
0.63
1.22
Year x Seed Treatment x Granular Nematicide
0.05
0.73
0.85 B
Table 2. Stand count, root-knot reproduction rate, and yield of corn as impacted by nematicide seed dressings and a granular nematicide at PBU over a three year study period.
Year
Plant
Population
#/ha
Root-knot
reproduction
ratioz
Yield
MT/hay
2012
---
245 a
9.91 a
2013
68662 a
42 b
8.22 b
2014
65049 b
211 a
6.14 c
Seed dressing and rate per 80,000 seedw
Curiser 5FS 0.5 mg a.i.
65393 a
145 a
7.65 b
Avicta Duo Corn mg a.i.
67630 a
154 a
8.15 a
Poncho 0.5 mg a.i.
69178 a
184 a
8.22 a
Poncho VOTiVO 0.5 mg a.i µg (B. firmis I-1582)
65049 a
180 a
8.28 a
Granular nematicide and rate/ha
Non-treated control
196 a
Counter 20G kg a.i.
64533 b
135 b
8.53 a
Z Data collected in 2013 and 2014.
Y Data collected in 2012.
X Significance at 0.10, 0.05, 0.01, and levels is indicated by ^, *, **, ***, respectively
RESULTS
While plant populations were impacted by year, seed treatment, and granular nematicide (GN), no interactions between these variables were noted and data are pooled. (Table 1). Despite similar seeding rates, higher plant populations were noted in 2013 than 2014 (Table 2). Mean plant populations for the IST and corresponding NST did not differ. However, lower plant populations were recorded for the Counter 20G GN than the control. In 2012, dry stalk weight was not impacted by NST, IST, or GN.
Significant year × seed treatment and seed treatment × GN interactions were recorded for fresh seedling weight (Table 1). In 2013, fresh seedling weight was higher for Poncho VOTiVO than for either IST but not Avicta Duo Corn, which also had higher fresh seedling weights than Poncho IST (Fig. 1). Among NST in 2014, higher fresh weights were recorded for Avicta Duo Corn than Poncho VOTiVO with intermediate fresh weights reported for both IST. In both years, similar fresh weights were recorded for both IST and Avicta Duo Corn, while higher fresh weights were noted for Poncho VOTiVO in 2013 than Higher seedling fresh weights were noted in 2013 and 2014 with Counter 20G compared with control (Fig. 2).
RKN reproduction rate differed by year and GN but not NST or IST (Table 1). Similarly higher reproduction rates were noted in 2012 and 2014 as compared with 2013 (Table 2). While the STI and NST had similar mean RKN reproduction rates, lower rates were noted for the Counter 20G- than non-treated corn (P<0.10).
Yield was significantly impacted by year, seed treatment, and granular nematicide (Table 1). Yield, which peaked in 2012, declined in the following two years with the lowest yields being recorded in 2014 (Table 2). Equally higher mean yields were noted for Avicta Duo Corn and Poncho VOTiVO along with the IST Cruiser compared with IST Poncho. A significant yield gain was also obtained with the GN Counter 20G than for the non-treated control.
z Plant population = number of plants per hectare.
y Root-knot reproduction ratio = final nematode count + 1(Pfinal+1)/initial nematode count + 1( Pinitial+1).
x Mean yields presented at 15.5% moisture.
w Means in each column that are followed by the same letter are not significantly different according to Fisher’s protected least significance (LSD) test (P<0.05), except for the reproduction ratio for the granular nematicide (P<0.10).
Figure 2. Total fresh seeding weight as influenced by year and seed treatment in 2013 and 2014 at PBU.
Figure 3. Total fresh weight as influenced by year and granular nematicide treatment in 2013 and 2014 at PBU.
zMeans followed by the same letter are not significantly different according to Fisher’s protected least significance (LSD) test (P<0.05).
zMeans followed by the same letter are not significantly different according to Fisher’s protected least significance (LSD) test (P<0.05).
Literature Cited:
Bowen, K. L., A. K. Hagan, H. L. Campbell, and S. Nightengale Effect of southern root-knot nematode (Meloidogyne incognita race 3) on corn yields in Alabama. Online. Plant Health Progress doi: /PHP RS.
Davis, R. F. and P. Timper Resistance of selected corn hybrids to Meloidogyne arenaria and M. incognita. J. Nematol. 32(Suppl.):
Gilhabert-Goya, M Phytobiome, a new view of crop production- an industry perspective. Phytopathology 105 (Suppl.):S65.
Hagan, A. K., H. L. Campbell, and J. R. Akridge a. Counter 15G nematicide and corn hybrid selection impacts yield and root-knot nematode juvenile counts Plant Disease Management Reports 6:N015.
Hagan, A. K., H. L. Campbell, and S. Nightengale b. Yield response and nematode control with Counter nematicide on corn, Plant Disease Management Reports 6:N005.
Ibrahim, I. K. A., S. A. Lewis, and D. C. Harshman Host suitability of graminaceous crop cultivars for isolates of Meloidogyne arenaria and M. incognita. J. Nematol. 25(Suppl.):
Lawrence, K. S., G. W. Lawrence, and S. Nightengale Efficacy of Counter for root knot nematode on corn in central Alabama, Plant Disease Management Reports 3:N013.
Williams, W. P. and G. L. Windham Resistance of corn to southern root-knot nematode. Crop Sci. 28:
SUMMARY
We showed that the granular nematicide Counter 20G reduced the rate of M. incognita reproduction on corn, which was reflected in higher seedling fresh weights ranging up to 45% and kernel gains of 0.9 to 1.4 MT/ha. In contrast to Counter 20G, Avicta Duo Corn and Poncho VOTiVO NST failed to increase seeding fresh weight, or limit M. incognita race 3 reproduction in corn when compared with their respective companion Cruiser and Poncho IST counterparts. Plant populations also were not impacted by any of the above NST or IST. Of the products screened, the GN Counter 20G consistently reduced RKN juvenile populations as well as boosted yield by 13.5%, while the NST failed to match the yields response recorded for the former GN. Based on our results, Counter 20G is the current treatment of choice for managing M. incognita race 3 on corn.