Differences in distribution and community structure of plant-parasitic nematodes in pecan orchards between two ecoregions of Georgia

Jagdale, Ganpati B.; Brenneman, Timothy B.; Severns, Paul M.; Shapiro-Ilan, David

doi:10.21307/jofnem-2021-075

Figures & Tables

3-D NMS ordination of PPN soil samples from 282 Pecan trees in the Piedmont and Coastal Plain ecoregions of Georgia, USA (Final stress of the 3-D NMS solution = 13.36, proportion of variance explained by all three axes combined = 0.911). Dark gray pyramids (▲) represent pecan soil samples collected from the Piedmont ecoregion (n = 60) and light gray pyramids (▲) represent soil samples collected from the Coastal Plant ecoregion (n = 222).Blue asterisk with names in bold text represent the centroids of the 11 PPN genera (sheath, lesion, cyst, dagger, lance, ring, RKN (root-knot), spiral, stunt, stubby root, pin (Praty)) in the 3-D NMS solution. Piedmont ecoregion soil samples were distributed from the left side of the NMS ordination space to the middle (front to back). Coastal Plain ecoregion soil samples were distributed primarily from the middle to the right side of ordination space. This spatial division of soil samples taken from the Piedmont and Coastal Plains ecoregions strongly suggests that the pecan PPN communities differ between ecoregions.

Survey of frequency and abundance of five major nematode genera on pecans in Georgia during 2017–2019 by county in two pecan growing ecoregions, Piedmont (P) and Coastal Plain (CP)_

		Meloidogyne			Paratrichodorus			Mesocriconema			Helichotylenchus			Xiphinema
County	N	PF^a	AB^b	MD^c	PF^a	AB^b	MD^c	PF^a	AB^b	MD^c	PF^a	AB^b	MD^c	PF^a	AB^b	MD^c
Clarke (P)	10	80	27	160	10	3	3	30	16	37	30	1	1	20	4	5
Rockdale (P)	10	10	7	7	20	2	2	80	3	6	100	20	69	70	1	1
Spalding (P)	10	30	24	50	–^d	–	–	40	2	2	100	23	111	30	1	1
Walton (P)	30	33	21	124	23	4	10	100	8	31	87	27	97	27	2	3
Appling (CP)	10	90	13	23	80	3	14	100	10	33	10	1	1	–	–	–
Berrien (CP)	09	44	188	658	22	2	3	56	16	41	11	1	1	–	–	–
Bibb (CP)	10	20	36	58	100	7	13	100	24	97	100	206	637	50	2	5
Colquitt (CP)	07	71	41	83	100	4	9	100	44	89	71	13	25	14	2	2
Cook (CP)	10	–	–	–	50	2	3	100	10	71	–	–	–	10	5	5
Crisp (CP)	12	58	11	43	58	3	5	83	14	49	58	28	100	42	2	5
Decatur (CP)	10	70	27	78	20	1	1	90	5	12	10	1	1	60	2	5
Dougherty (CP)	10	50	5	11	50	3	5	100	24	45	20	2	2	20	1	1
Grady (CP)	10	–	–	–	20	1	1	90	18	46	60	3	4	40	6	14
Houston (CP)	14	43	14	34	14	2	2	93	54	293	14	16	30	36	3	9
Irwin (CP)	10	40	38	67	40	2	3	100	49	309	–	–	–	–	–	–
Jefferson (CP)	10	70	10	60	70	3	8	90	40	121	10	1	1	40	1	1
Lee (CP)	10	30	2	2	–	–	–	100	11	26	–	–	–	–	–	–
Mitchell (CP)	10	40	5	12	70	4	14	90	37	121	50	3	5	10	2	2
Peach (CP)	20	15	35	84	95	10	29	85	18	72	95	27	187	50	2	4
Taylor (CP)	10	40	1	1	20	3	4	90	6	27	–	–	–	20	3	3
Tift (CP)	10	70	11	36	60	3	3	100	20	49	–	–	–	–	–	–
Turner (CP)	10	30	39	104	10	1	1	100	20	62	40	2	6	90	3	5
Ware (CP)	10	20	3	4	10	1	1	100	11	31	10	1	1	20	2	3
Wilcox (CP)	10	70	22	119	30	4	6	90	16	36	10	13	13	10	1	1
Worth (CP)	10	80	18	64	10	1	1	100	28	60	–	–	–	40	2	4

Indicator Species Analysis (see Severns and Sykes, 2020 for an analysis description) results showing which PPN nematodes were statistically associated (*) with pecan soil samples from the Piedmont (60 soil samples) or Coastal Plain (222 soil samples) ecoregions of Georgia, USA_

Nematode genus	Indicator value (0–100)	Ecoregion	p value (from 5,000 randomizations)
Ring, Mesocriconema spp.*	73.8	Coastal Plain	0.0002
Spiral, Helichotylenchus spp.*	48.1	Piedmont	0.0002
Stubby-root, Paratrichodorus spp.*	36.1	Coastal Plain	0.0028
Root-knot, Meloidogyne spp.	24.4	Coastal Plain	0.69
Dagger, Xiphinema spp.	15.3	Piedmont	0.85
Sheath, Hemicycliophora spp.*	14.8	Piedmont	0.0002
Lesion, Pratylenchus spp.*	13.0	Piedmont	0.0002
Lance, Hoplolaimus spp.	5.8	Coastal Plain	0.28
Pin, Paratylenchus spp.	3.6	Coastal Plain	0.64
Stunt, Tylenchorhynchus spp.	3.3	Coastal Plain	0.83
Cyst, Heterodera spp.	2.0	Coastal Plain	0.71

Frequency of occurrence and abundance of plant-parasitic nematodes in commercial pecan orchards from two ecoregions of Georgia, 2017–2019_

	Coastal Plain region								Piedmont region
					Mean percentages of 6 soil samples								Mean percentages of 4 soil samples
Nematode genus	PF^a	ABN^b	STD	MD^c	Sand	Silt	Clay	pH	PF^a	ABN^b	STD	MD^c	Sand	Silt	Clay	pH
Heterodera	2	35	9.3	138	87.5	5.92	6.56	6.6	3	4	0.7	5	65.5	17.25	17.28	5.45
Xiphinema	28	3	1.6	14	87.5	5.92	6.56	6.6	33	2	1.0	5	65.5	17.25	17.28	5.45
Hoplolaimus	7	4	1.5	15	87.5	5.92	6.56	6.6	3	2	0.4	2	65.5	17.25	17.28	5.45
Pratylenchus	1	1	0.1	1	87.5	5.92	6.56	6.6	13	4	1.5	7	65.5	17.25	17.28	5.45
Paratylenchus	1	6	2.9	42	87.5	5.92	6.56	6.6	3	4	0.7	5	65.5	17.25	17.28	5.45
Mesocriconema	93	23	35.2	309	87.5	5.92	6.56	6.6	75	7	7.2	37	65.5	17.25	17.28	5.45
Meloidogyne	44	25	47.6	658	87.5	5.92	6.56	6.6	37	23	27.0	160	65.5	17.25	17.28	5.45
Hemicycliophora	1	1	0.1	1	87.5	5.92	6.56	6.6	15	3	1.3	6	65.5	17.25	17.28	5.45
Helichotylenchus	30	44	58.6	637	87.5	5.92	6.56	6.6	82	23	27.7	111	65.5	17.25	17.28	5.45
Paratrichodorus	46	5	4.2	29	87.5	5.92	6.56	6.6	17	3	1.6	10	65.5	17.25	17.28	5.45
Tylenchorhynchus	4	23	11.1	164	87.5	5.92	6.56	6.6	8	2	0.9	6	65.5	17.25	17.28	5.45

Plant-parasitic nematodes found in commercial pecan orchards in Georgia in 2017, 2018, and 2019_

County	Nematode genera and ecoregions
Piedmont region
Clarke	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema, Paratylenchus, Hemicycliophora, Heterodera
Rockdale	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema
Spalding	Meloidogyne, Mesocriconema, Tylenchorhynchus, Helichotylenchus, Xiphinema
Walton	Meloidogyne, Hoplolaimus, Pratylenchus, Paratrichodorus, Mesocriconema, Tylenchorhynchus, Helichotylenchus, Hemicycliophora, Xiphenema
Coastal Plain region
Appling	Meloidogyne, Hoplolaimus, Paratrichodorus, Mesocriconema, Helichotylenchus
Berrien	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus
Bibb	Meloidogyne, Pratylenchus, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema
Colquitt	Meloidogyne, Paratrichodorus, Mesocriconema, Tylenchorynchus, Helichotylenchus, Xiphinema
Cook	Paratrichodorus, Mesocriconema, Xiphenema
Crisp	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema and Heterodera
Decatur	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema
Dougherty	Meloidogyne, Hoplolaimus, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema, Paratylenchus
Grady	Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema
Houston	Meloidogyne, Hoplolaimus, Pratylenchus, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema
Irwin	Meloidogyne, Paratrichodorus and Mesocriconema
Jefferson	Meloidogyne, Paratrichodorus, Mesocriconema, Tylenchorhynchus, Helichotylenchus, Xiphinema
Lee	Meloidogyne, Mesocriconema
Mitchell	Meloidogyne, Hoplolaimus, Pratylenchus, Paratrichodorus, Mesocriconema, Helichotylenchus,Xiphinema, Paratylenchus
Peach	Meloidogyne, Hoplolaimus, Pratylenchus, Paratrichodorus, Mesocriconema, Tylenchorhynchus, Helichotylenchus, Xiphinema
Taylor	Meloidogyne, Paratrichodorus, Mesocriconema, Xiphinema
Tift	Meloidogyne, Paratrichodorus, Mesocriconema, Tylenchorhynchus, Paratylenchus
Turner	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus, Xiphinema, Paratylenchus, Hemicycliophora
Ware	Meloidogyne, Hoplolaimus, Paratrichodorus, Mesocriconema, Helichotylenchus and Xiphinema
Wilcox	Meloidogyne, Paratrichodorus, Mesocriconema, Helichotylenchus,Xiphinema
Worth	Meloidogyne, Paratrichodorus, Mesocriconema, Xiphinema

Differences in distribution and community structure of plant-parasitic nematodes in pecan orchards between two ecoregions of Georgia

Figures & Tables

Figure 1:

Survey of frequency and abundance of five major nematode genera on pecans in Georgia during 2017–2019 by county in two pecan growing ecoregions, Piedmont (P) and Coastal Plain (CP)_

Indicator Species Analysis (see Severns and Sykes, 2020 for an analysis description) results showing which PPN nematodes were statistically associated (*) with pecan soil samples from the Piedmont (60 soil samples) or Coastal Plain (222 soil samples) ecoregions of Georgia, USA_

Frequency of occurrence and abundance of plant-parasitic nematodes in commercial pecan orchards from two ecoregions of Georgia, 2017–2019_

Plant-parasitic nematodes found in commercial pecan orchards in Georgia in 2017, 2018, and 2019_

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