Effect of environmental conditions on fluopyram applied in-furrow on cotton nematodes

Test	Year	Soil texture^c	Dates of activities		Days until first rain	Rain^b (cm)	Avg. air temp^a(^°C)	Galls/plant				Lint yield (kg/ha)				N ^d
			Dates of activities					No nematicide		Fluopyram		No nematicide		Fluopyram
			Plant	Roots dug				Mean value	SD	Mean value	SD	Mean value	SD	Mean value	SD
1	2014	LS	5/19	7/9	5	1.98	23.1	7.7	5.9	3.2	2.3	969	264	1,061	172	12
2	2015	LS	5/11	7/3	2	2.54	19.1	12.2	20.1	6.2	7.0	1,083	147	1,147	85	12
3	2016	LS	5/27	7/8	4	3.05	24.7	15.5	8.6	7.4	7.2	1,473	84	1,559	88	16
4	2017	LS	5/11	6/29	8	1.27	20.6	20.2	8.8	21.4	7.7	1,116	273	1,213	185	8
5	2017	LS	5/10	6/29	9	1.27	20.4	16.6	3.7	15.8	7.8	1,230	171	1,513	148	12
6	2018	LS	5/14	7/17	6	2.13	25.8	7.7	3.2	7.0	4.2	700	202	757	159	16
7	2019	LS	5/18	6/28	16	2.54	22.2	7.7	2.0	6.4	1.9	823	96	749	99	8
8	2019	LS	5/18	6/28	16	2.54	22.2	10.0	6.3	11.0	4.7	1,385	196	1,514	123	8
9	2019	LFS	5/14	7/11	6	3.40	22.1	17.5	9.7	14.0	5.3	2,423	131	2,531	159	8
10	2021	LS	5/24	7/12	1	2.54	22.1	12.0	4.6	19.7	11.0	1,161	128	1,261	140	8
11	2021	LS	5/13	6/30	2	1.12	22.2	17.8	9.9	12.8	5.0	—	--^e	—	--	8
12	2023	SL	6/2	7/12	0	2.29	21.4	14.4	8.0	7.8	5.6	1,020	188	894	106	9
13	2023	SL	5/18	7/7	1	0.99	20.9	15.6	12.3	18.3	15.3	1,100	108	976	185	8
14	2024	SL	5/24	7/9	5	2.31	24.3	12.7	6.7	5.5	4.5	744	132	892	142	16
15	2025	SCL	6/2	7/24	1	4.29	25.0	29.0	15.8	13.3	5.6	1,401	172	1,672	131	10

[i] ^aAverage air temperature for 14 days after planting.

[ii] ^bAmount of rain in the first rain event after planting.

[iii] ^cLS is loamy sand, LFS is loamy fine sand, SL is sandy loam, and SCL is sandy clay loam.

[iv] ^d N is the total number combined of no nematicide and fluopyram-treated plots for the site/year.

[v] ^eTest destroyed by hail before harvest time.

Table 2

Environmental parameters associated with fluopyram (F^c) trials in Rotylenchulus reniformis fields

Test	Year	Date of activities		Days until first rain	Rain^b (cm)	Avg. air temp^a(°C)	Reniform nematode/100 cm³ soil				Lint yield (kg/ha)				N ^c
		Date of activities					No nematicide		Fluopyram		No nematicide		Fluopyram
		Plant	Soil sampling				Mean value	SD	Mean value	SD	Mean value	SD	Mean value	SD
16	2014	5/10	7/9	13	4.1	21.3	165	124	118	101	812	116	749	131	16
17	2015	5/27	7/15	41	7.6	22.8	590	386	655	714	884	98	1,014	192	12
18	2016	5/6	7/18	3	7.6	18.9	535	187	418	280	734	208	657	170	12
19	2017	5/16	7/11	1	7.6	21.4	832	203	912	567	833	174	841	248	10
20	2018	5/29	7/24	5	2.3	27.9	240	209	170	168	370	91	483	37	8
21	2018	5/15	7/27	0	1.6	25.5	1,194	756	1,308	777	439	73	452	56	16
22	2019	5/31	7/15	2	1.8	21.7	592	443	360	303	577	143	536	125	10
23	2020	5/22	6/28	2	10.3	22.8	590	453	760	287	700	142	689	118	8
24	2021	6/8	7/24	18	3.2	28.3	860	761	1,510	1,449	395	58	470	91	8
25	2022	5/20	6/27	4	4.4	22.7	345	225	230	136	425	162	354	78	8
26	2022	5/20	6/24	4	4.4	22.7	113	50	47	12	756	22	943	118	6
27	2023	6/7	7/28	39	1.8	25.0	350	147	280	190	879	150	895	123	8
28	2023	6/7	7/19	39	1.8	25.0	110	119	110	115	434	48	488	39	8
29	2023	6/2	7/17	0	2.3	22.5	528	354	352	182	806	144	788	87	10
30	2024	5/22	6/27	7	1.5	24.0	92	110	112	64	673	152	688	82	10
31	2024	5/21	6/26	8	1.5	23.9	320	69	240	97	459	50	452	63	8
32	2024	5/21	6/26	8	1.5	23.9	615	500	700	202	346	67	284	55	8
33	2025	5/19	7/11	2	5.1	22.7	212	116	100	54	683	54	662	101	8

[i] ^aAverage air temperature for 14 days after planting.

[ii] ^bAmount of rain in the first rain event after planting.

[iii] ^c N is the total number combined of no nematicide and fluopyram-treated plots for the site/year.

Table 3

Pearson correlation coefficients between environmental variables^a and measured plant and nematode variables, with and without fluopyram (F) in root-knot nematode trials

	F^c	First rain	Days	Air temp	Rain30	Stand	Galls
First rain	A
Days	A	0.03
Air temp.	A	−0.04	−0.03
Rain30	A	0.51***^b	−0.56***	−0.27**
Stand	N	0.28*	0.29*	−0.32**	−0.04
Galls	N	−0.14	−0.23*	−0.20	0.09	−0.22
Yield	N	0.31**	−0.04	−0.64***	0.15	0.32**	0.26*
Stand	F	0.10	0.42***	−0.22	−0.30**
Galls	F	−0.33**	−0.02	-0.21	-0.22	0.04
Yield	F	0.21	0.01	-0.56***	0.10	0.30**	0.25*

[i] ^aFirst rain is the amount of the first rain after planting; Days is the number of days until the first rain after planting; Air temp is the average air temperature for the first 14 days after planting; Rain30 is the amount of rain for the first 30 days after planting; Stand is the plant stand; Galls is the number of galls per plant typically taken 45–60 days after planting; Yield is the cotton lint yield in a plot.

[ii] ^b***, **, and * indicate significant at P = 0.001, 0.01, and 0.05, respectively.

[iii] ^cA indicates all plots (with and without fluopyram), N stands for the no nematicide plots, and F stands for plot treated with fluopyram only.

Effect of fluopyram and various environmental parameters including (a) amount of the first rain after planting (interaction with rain amount and fluopyram), No Fluopyram $Galls = 17.29 - (1.523 \times rain)$ , with Fluopyram $Galls = 16.25 - (2.820 \times rain)$ ; (b) number of days until the first rain after planting (not significant for this parameter); and (c) average air temperature for the first 14 days after planting (not significant for this parameter), on galls/plant in *Meloidogyne incognita* infested field trials. Squares are the least square means for fluopyram (solid) and no nematicide (open) treatments, respectively in a trial. The two treatments have the same color for a given trial per environmental value. Red and blue squares are associated with negative responses, when root galling was higher in fluopyram-treated plots than no nematicide, while green, black, and purple are associated with positive responses, when root galling was lower in fluopyram-treated plots than no nematicide. When an environmental parameter affected root galls significantly as an interaction with treatment, the predicted lines for no nematicide and fluopyram treatments are a dashed and solid line, respectively.

Effect of fluopyram and various environmental parameters including (a) amount of the first rain after planting (interaction with fluopyram), No fluopyram: $Lint yield = 876.1 + (157.40 \times rain),$ with fluopyram: $Lint yield = 972.8 + (152.1 \times rain)$ ; (b) number of days until the first rain after planting (not significant for this parameter); and (c) average air temperature for the first 14 days after planting, on cotton lint yield in *Meloidogyne incognita* infested field trials (interaction with fluopyram), No fluopyram: $Lint yield = 5507.0 - (177.5 \times air temperature)$ , With fluopyram: $Lint yield = 5587.4 - (177.4 \times air temperature)$ . Squares are the least square means for fluopyram (solid) and no nematicide (open) treatments, respectively in a trial. The two treatments have the same color for a given trial per environmental value. Red and blue squares are associated with negative responses, when lint yield was lower in fluopyram-treated plots than no nematicide, while green, black, and purple are associated with positive responses, when lint yield was higher in fluopyram-treated plots than no nematicide. When an environmental parameter affected lint yield significantly as an interaction with fluopyram, then the predicted lines for no nematicide and fluopyram treatments are a dashed and solid line, respectively.

Table 4

Pearson correlation coefficients between environmental variables^a and measured plant and nematode variables with and without fluopyram (F) in reniform nematode trials

−	F^c	First rain	Days	Temp	Rain30	Stand	Ren	LREN
First rain	A		0.02	−0.53***	0.30***
Days	A	0.02		0.21**	−0.34***
Temp	A	−0.53***	0.21**		−0.47***
Rain30	A	0.30***	−0.34***	−0.47***
Stand	N	−0.20	0.04	0.06	0.01
Ren	N	0.04	−0.19	0.13	−0.22*	−0.01
LREN	N	0.16	−0.23*	−0.01	−0.16	0.02	0.77***
Yield	N	0.43***	0.16	−0.54***		−0.17	−0.13	0.01
Stand	F	−0.16	0.07	0.01	0.02
Ren	F	0.07	−0.05	0.24*	−0.19	−0.01
LREN	F	0.19	−0.04	0.06	−0.16	0.04	0.76***
Yield	F	0.45***	0.37***	−0.33**	−0.09	−0.06	−0.14	−0.12

[i] ^aFirst rain is the amount of the first rain after planting; Days is the number of days until the first rain after planting; Air temp is the average air temperature for the first 14 days after planting; Rain30 is the amount of rain for the first 30 days after planting; Stand is the plant stand; Ren is the vermiform reniform nematodes taken typically 45–60 days after planting; LREN is a LOG₁₀ transformation of Ren/100 cm³ soil; Yield is the cotton lint yield in a plot.

[ii] ^b***, **, and * indicate significant at P = 0.001, 0.01, and 0.05, respectively.

[iii] ^cA indicates all plots (with and without fluopyram), N stands for the no nematicide plots, and F stands for plot treated with fluopyram only.

*Rotylenchulus reniformis* vermiform stages (REN)/100 cm³ soil, with a LOG₁₀ transformation (LREN) as affected by the amount of rain in the first rain after planting. Squares are the least square means for fluopyram (solid) and no nematicide (open) treatments, respectively in a trial. The two treatments have the same color for a given trial per environmental value. Red and blue squares are associated with negative responses, when LREN was higher in fluopyram-treated plots than no nematicide, while green, black, and purple are associated with positive responses, when LREN was lower in fluopyram-treated plots than no nematicide. The amount of the first rain after planting affected LREN, but nematicide did not, so the single line is predicted LREN based only on rain amount.

Effect of fluopyram and various environmental parameters including (a) amount of the first rain after planting (interaction with fluopyram), No nematicide: $Lint yield = 498.0 + (33.54 \times rain)$ , With fluopyram: $Lint yield = 498.5 + (34.86 \times rain)$ ; (b) number of days until the first rain after planting (interaction with fluopyram), No nematicide: $Lint yield = 605.1 + (2.158 \times days)$ , With fluopyram: $Lint yield = 587.0 + (4.477 \times days)$ ; and (c) average air temperature for the first 14 days after planting (interaction with fluopyram), No nematicide: $Lint yield = 1773.0 - (48.81 \times air temperature)$ , With fluopyram: $Lint yield = 1415.7 - (33.27 \times air temperature)$ , on cotton lint yield in *Rotylenchulus reniformis* infested field trials. Squares are the least square means for fluopyram (solid) and no nematicide (open) treatments, respectively in a trial. The two treatments have the same color for a given trial per environmental value. Red, blue, or orange squares are associated with negative responses, when lint yield was lower in fluopyram-treated plots than no nematicide, while green, black, and purple are associated with positive responses, when lint yield was higher in fluopyram-treated plots than no nematicide. When an environmental parameter affected lint yield significantly as an interaction with fluopyram, then the predicted lines for no nematicide and fluopyram treatment are a dashed and solid line, respectively.

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DOI: https://doi.org/10.2478/jofnem-2026-0021 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X

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Language: English

Page range: 234 - 245

Submitted on: Jan 28, 2026

Accepted on: Mar 30, 2026

Published on: Jul 28, 2026

Published by: Society of Nematologists, Inc.

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

Keywords:

Cotton,

Fluopyram,

Meloidogyne incognita,

Nematode Management,

Rotylenchulus reniformis,

Related subjects:

© 2026 Terry A. Wheeler, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 58 (2026): Issue 1 (February 2026)

Effect of environmental conditions on fluopyram applied in-furrow on cotton nematodes

Figures & Tables

Table 1

Table 2

Table 3

Fig. 1

Fig. 2

Table 4

Fig. 3

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