The Efficacy of Entomopathogenic Nematodes Plus an Adjuvant against Helicoverpa zea and Chrysodeixis includens in Aboveground Applications

Zhang, Minling; Spaulding, Nathan; Reddy, Gadi V.P.; Shapiro-Ilan, David I

The Efficacy of Entomopathogenic Nematodes Plus an Adjuvant against Helicoverpa zea and Chrysodeixis includens in Aboveground Applications

Journal of Nematology

Volume 56 (2024): Issue 1 (March 2024)

By:

Minling Zhang, Nathan Spaulding, Gadi V.P. Reddy and David I Shapiro-Ilan

Open Access

|May 2024

Figures & Tables

EPN infection on eggs of Helicoverpa zea and Chrysodeixis includens. (A) An infectious juvenile of Steinernema carpocapsae (all strain) was infecting an egg of H. zea with part of its body inside the egg. (B) An infected egg of H. zea by Heterorhabditis georgiana (kesha strain), from which 50 progeny juveniles were produced. (C) A larva of H. zea killed inside an egg by H. floridensis (K22) with young juveniles inside four adult female nematodes. (D) A larva of C. includens killed inside an egg by a juvenile of S. feltiae (SN). (E) A head capsule of a C. includens larva left after a juvenile of S. feltiae (SN) developed inside the egg. (F) A head capsule of a C. includens larva inside an egg with newly emerged juveniles of S. feltiae (SN).

Larvae of (A) Helicoverpa zea and (B) Chrysodeixis includens inside eggs where larvae biting the eggshells and the protruding hairs of larvae were visible. (C) An adult of Heterorhabditis floridensis (K22 strain) from an H. zea egg with a few juveniles inside its body, and (D) two adults of Steinernema carpocapsae (all strain) from a fifth instar of C. includens with many juveniles inside one adult and eggs inside another.

EPN infection of larvae and pupae of Helicoverpa zea and Chrysodeixis includens. (A) Adults of Steinernema rarum (17c+e strain) inside a larva of H. zea. (B) Large adults of S. carpocapsae (all) inside the head of C. includens larva. (C) Juveniles of S. riobrave (7–12) from a pupa of H. zea in a White trap. (D) Adults of Heterorhabditis georgiana (kesha strain) inside a pupa of Chrysodeixis includens.

EPN suspension with and without an adjuvant. (A) Without an adjuvant, suspension was distributed unevenly on a corn leaf; air bubbles were visible. (B) With SAg Surfactant, suspension was distributed evenly across the corn leaf, which may help nematodes to find hosts and hide in pores on a corn leaf. (C) Without an adjuvant, many EPNs were trapped in water droplets, including on the leaf and insect. (D) With SAg Surfactant, a juvenile was able to search and move around more freely, allowing it to attempt to hide in a small leaf gap when the leaf was getting dry.

Effect of Steinernema carpocapsae (all strain) with an adjuvant on first instars of Helicoverpa zea in corn plants in a corn field (2022, Leland, Mississippi)_

Field exp., # Experiment date Temperature RH Weather condition	EPN Rate Plant Age Plant high	Treatment	# of Insects	% Mortality ± SEM	% EPN Infection ± SEM
Field exp, #1	20 IJs/cm²	S. carpocapsae (All) + SAg^	63	78.2 ± 9.2 a	35.0 ± 10.3 a
June 17, 2022	20 IJs/cm²	S. carpocapsae (All) + SAg^	63	78.2 ± 9.2 a	35.0 ± 10.3 a
24(23–35) °C^a	6 wk	S. carpocapsae (All)	56	69.3 ± 7.8 a	24.2 ± 10.2 a
82(62–99) %RH	1.1 m	Water + SAg	64	22.0 ± 4.6 b	0.0 ± 0.0 b
30 min heavy rain		Water	53	28.0 ± 8.1 b	0.0 ± 0.0 b
				F(3, 12)=20.66	F(3, 12)=10.95
				P < 0.0001	P < 0.0009
Field exp., #2	40 IJs/cm²	S. carpocapsae (All) + SAg	80	87.7 ± 1.1 a	66.4 ± 4.7 a
June 27, 2022	40 IJs/cm²	S. carpocapsae (All) + SAg	80	87.7 ± 1.1 a	66.4 ± 4.7 a
22(19–30) °C	7.5 wk	S. carpocapsae (All)	58	70.4 ± 3.6 b	42.0 ± 2.5 b
83(58–94) %RH	1.3 m	Water + SAg	65	18.7 ± 4.5 c	0.0 ± 0.0 c
Partly Cloudy		Water	74	21.6 ± 3.1 c	0.0 ± 0.0 c
				F(3, 12)=77.26	F(3, 12)=294.09
				P < 0.0001	P < 0.0001)

Effect of Steinernema riobrave (7–12 strain) and Steinernema carpocapsae (all strain) with an adjuvant on fifth instars of Chrysodeixis includens on soybean plants in soybean fields (2022, Leland, Mississippi)_

Experiment date Temperature RH Weather condition	EPN rate Plant age Plant high	Treatment	# of Insects	% Mortality ± SEM	% EPN Infection ± SEM
Field exp., #1 August 3, 2022	40 IJs/cm²	S. carpocapsae (All) + SAg^	37	92.9 ± 4.7 a	37.1 ± 7.6 a
24(22–35) °C^a	9 wk	S. riobrave (7–12) + SAg	51	25.2 ± 12.6 b	0.0 ± 0.0 b
88(60–97) %RH	0.5 m	Water + SAg	38	13.0 ± 7.2 b	0.0 ± 0.0 b
Most sunny				F(2, 9)=16.82	F(2, 9)=58.4
				P=0.0009	P < 0.0001

Field exp., #2 September 8, 2022	10 IJs/cm²	S. carpocapsae (All) + SAg	95	23.7 ± 4.8 a	7.1 ± 1.4 a
22(19–32) °C	8 wk	S. riobrave (7–12) + SAg	91	6.2 ± 1.3 b	0.0 ± 0.0 b
79(40–95) %RH	0.4 m	Water + SAg	84	1.09 ± 1.1 b	0.0 ± 0.0 b
Sunny				F(2, 9)=21.28	F(2, 9)=73.04
				P=0.0004	P < 0.0001

Entomopathogenic nematodes infection (% ± SEM)) on eggs of Helicoverpa zea and Chrysodeixis includens in the laboratory (25°C, 85% RH)_

EPN strain	*H. zea*		*C. includens*

	Unfertilized eggs^a	Mixed eggs	Mixed eggs
Heterorhabditis bacteriophora (HP88)	0.0 ± 0.0 a	5.0 ± 3.4 ab	6.7 ± 3.3 a
Heterorhabditis bacteriophora (VS)	1.7 ± 1.7 a	1.7 ± 1.7 ab	0.0 ± 0.0 a
Heterorhabditis floridensis (K22)	6.7 ± 3.3 a	10.0 ± 6.3 ab	0.0 ± 0.0 a
Heterorhabditis georgiana (kesha)	0.0 ± 0.0 a	11.7 ± 4.0 a	0.0 ± 0.0 a
Steinernema carpocapsae (All)	1.7 ± 1.7 a	0.0 ± 0.0 b	1.7 ± 1.7 a
Steinernema carpocapsae (Cxrd)	1.7 ± 1.7 a	3.3 ± 1.7 ab	1.7 ± 1.7 a
Steinernema feltiae (SN)	0.0 ± 0.0 a	3.3 ± 2.1 ab	6.7 ± 4.9 a
Steinernema rarum (17c+e)	0.0 ± 0.0 a	1.7 ± 1.7 ab	0.0 ± 0.0 a
Steinernema riobrave (355)	1.7 ± 1.7 a	6.7 ± 2.1 ab	0.0 ± 0.0 a
Steinernema riobrave (7–12)	1.7 ± 1.7 a	0.0 ± 0.0 b	3.3 ± 3.3 a
Water	0.0 ± 0.0 a	0.0 ± 0.0 b	0.0 ± 0.0 a

F-value (10, 55)	1.53	2.64	1.64
P-value	0.1534	0.0104	0.1193

Mortality (% ± SEM) of first to fourth instars, fifth instars, and pupae of Helicoverpa_ zea and Chrysodeixis includens caused by 10 entomopathogenic nematode strains in the laboratory (25°C, 85% RH)_

EPN strains	*H. zea*			*C. includens*			**H. zea and C. includens**

	First-fourth instars	Fifth instars	Pupae	First-fourth instars	Fifth instars	Pupae	Avg of first-fourthand fifth instars^a
Heterorhabditis bacteriophora (HP88)	100.0 ± 0.0 a	81.7 ± 6.0 ab	6.7 ± 4.9 ab	80.0 ± 7.3 a	96.7 ± 2.1 a	33.3 ± 11.7 abc	89.6
Heterorhabditis bacteriophora (VS)	98.3 ± 1.7 a	81.7 ± 4.8 ab	15.0 ± 4.3 ab	72.6 ± 5.4 ab	93.3 ± 4.9 a	40.0 ± 11.8 ab	86.5
Heterorhabditis floridensis (K22)	98.3 ± 1.7 a	85.0 ± 7.6 ab	21.7 ± 8.7 ab	88.3 ± 3.1 a	100.0 ± 0.0 a	30.0 ± 8.9 abc	92.9 (top 5)
Heterorhabditis georgiana (kesha)	100.0 ± 0.0 a	83.3 ± 4.2 ab	13.3 ± 4.2 ab	90.0 ± 4.5 a	95.0 ± 3.4 a	45.0 ± 5.0 ab	92.0 (top 5)
Steinernema carpocapsae (All)	100.0 ± 0.0 a	95.0 ± 3.4 a	20.0 ± 6.8 ab	85.0 ± 2.2 a	98.3 ± 1.7 a	41.7 ± 9.5 ab	94.6 (top 5)
Steinernema carpocapsae (Cxrd)	100.0 ± 0.0 a	85.0 ± 8.1 ab	21.7 ± 6.0 ab	80.0 ± 8.6 a	98.3 ± 1.7 a	36.7 ± 12.3 ab	90.8
Steinernema feltiae (SN)	100.0 ± 0.0 a	76.7 ± 6.7 ab	5.0 ± 2.2 ab	40.0 ± 5.8 b	95.0 ± 3.4 a	18.3 ± 6.0 bc	77.9
Steinernema rarum (17c+e)	100.0 ± 0.0 a	58.3 ± 13.8 b	13.3 ± 5.6 ab	71.7 ± 7.4 ab	88.3 ± 7.9 a	26.7 ± 4.9 abc	79.6
Steinernema riobrave (355)	100.0 ± 0.0 a	88.3 ± 5.4 ab	21.7 ± 6.5 a	86.7 ± 6.1 a	100.0 ± 0.0 a	61.7 ± 7.0 a	93.8 (top 5)
Steinernema riobrave (7–12)	100.0 ± 0.0 a	93.3 ± 4.9 a	15.0 ± 4.3 ab	90.0 ± 5.2 a	98.3 ± 1.7 a	63. 3 ± 4.2 a	95.4 (top 5)
Water	3.3 ± 3.3 b	0.0 ± 0.0 c	0.0 ± 0.0 b	0.0 ± 0.0 c	0.0 ± 0.0 b	1.7 ± 1.7 c	0

F-Value (10, 55)	187.99	15.81	2.42	18.4	41.62	4.99
P-Value	<.0001	<.0001	0.0184	<.0001	<.0001	<.0001

DOI: https://doi.org/10.2478/jofnem-2024-0018 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X

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Language: English

Submitted on: Jan 17, 2024

Published on: May 8, 2024

Published by: Society of Nematologists, Inc.

In partnership with: Paradigm Publishing Services

Publication frequency: 1 times per year

Keywords:

entomopathogenic nematode,

adjuvant

Related subjects:

Life sciences,

Life sciences, other

© 2024 Minling Zhang, Nathan Spaulding, Gadi V.P. Reddy, David I Shapiro-Ilan, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.

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The Efficacy of Entomopathogenic Nematodes Plus an Adjuvant against Helicoverpa zea and Chrysodeixis includens in Aboveground Applications

Figures & Tables

Figure 1:

Figure 2:

Figure 3:

Figure 4:

Effect of Steinernema carpocapsae (all strain) with an adjuvant on first instars of Helicoverpa zea in corn plants in a corn field (2022, Leland, Mississippi)_

Effect of Steinernema riobrave (7–12 strain) and Steinernema carpocapsae (all strain) with an adjuvant on fifth instars of Chrysodeixis includens on soybean plants in soybean fields (2022, Leland, Mississippi)_

Entomopathogenic nematodes infection (% ± SEM)) on eggs of Helicoverpa zea and Chrysodeixis includens in the laboratory (25°C, 85% RH)_

Mortality (% ± SEM) of first to fourth instars, fifth instars, and pupae of Helicoverpa_ zea and Chrysodeixis includens caused by 10 entomopathogenic nematode strains in the laboratory (25°C, 85% RH)_

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