Biological Control of Tobacco Cutworm, Spodoptera litura (Lepidoptera: Noctuidae) by Steinernematid and Heterorhabditid Entomopathogenic Nematodes

Abstract

: Five effective strains against tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuidae), Steinernema carpocapsae (GSN1), Steinernema sp. (GSNUS-10), Steinernema sp. (GSNUS-14), Heterorhabditis bacteriophora Hamyang (HbH), and Heterorhabditis sp. (GSNUH-1) were selected among 14 isolates of Korean entomopathogenic nematode in laboratory tests. LC 50 values of above five strains against tobacco cutworm were various by different nematode strains and developmental stages of tobacco cutworm. LC 50 value of S. carpocapsae (GSN1) was the lowest by 4.0~8.3 infective juveniles (Ijs) and 2nd instars of tobacco cutworm was most susceptible. Pathogenicity of five effective strains against tobacco cutworm depends on nematode strain, concentration, and application times. The most effective strain was determined as S. carpocapsae (GSN1). Two or three times of applications were effective regardless of nematode strain, or concentration. Efficacy of S. carpocapsae (GSN1), Steinernema (GSNUS-10), Steinernema (GSNUS-14), and Heterorhabditis (GSNUH-1) was variable depending on nematode strain, concentration, application times, and host variety. S. carpocapsae (GSN1) was the most effective and inoculation of 100,000 infective juveniles per m 2 (720,000 Ijs/7.2 m 2 =1×10 9 Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale.

Virulence of new South Carolinian heterorhabditid isolates (Rhabditida: Heterorhabditidae) to the beet armyworm, Spodoptera exigua

“…All the heterorhabditid strains tested showed high virulence to 4th instars of the beet armyworm, producing a significantly higher mortality (53.6-100%) at all concentrations than the untreated control at the final count. Apparently, they are effective bio-control agents of S. exigua and our results corroborate the finding of the study of Kim et al (2006). However, environmental factors such as soil structure, temperature, humidity and host density under greenhouse and field conditions have huge impact on the efficacy of EPN (Koppenhöfer, 2000;Georgis et al, 2006).…”

“…Mortalities were higher, LC 50 values were lower and LT 50 values were shorter for these nematodes. Kim et al (2006) reported that LC 50 value of H. bacteriophora Hamyang strain was 5.5 IJs per 4 th instar of the beet armyworm. This value is the same as LC 50 s of H. bacteriophora WPS and HP88 strains (5.5 IJs per larva) and close to H. bacteriophora SMP strain (6.1 IJs per larva) in our study.…”

“…These nematodes are effective biocontrol agents of a variety of economically important insect pests (Klein, 1990;Shapiro-Ilan et al, 2002;Grewal et al, 2005) and they have been used in controlling insect pest for about 25 years, extending their usage from high value markets to large area crops, including forestry (Peters, 2010). A number of studies indicate that applications of EPN can result in high levels of control for a variety of noctuid pests including S. exigua (Feaster and Steinkraus, 1996;Medeiros et al, 2000;González-Ramírez et al, 2000;Kim et al, 2006;Kepenekçi and Evlice, 2009).…”

Biology and integrated management of tobacco caterpillar, Spodoptera litura Fab.: A systematic review

“…Biological management approach refers to the administration of beneficial entomopathogenic organisms and use of biopesticides and bio stimulants (Baker et al, 2020). Application of Steinernema carpocapsae in field can give reduction of Spodoptera population in Chinese cabbage field (Kim et al, 2008). Aqueous extraction from leaves of Lantana camara L. (Verbenaceae) and spray at the concentration of 40 % caused 96.6 % mortality in cabbage field (Desmukhe et al, 2011).…”

Pathogenicity bioassay of entomopathogenic nematode, Steinernema carpocapsae GSN1 strain (Nematoda: Steinernematidae) on the shiitake fungus moth, Morophagoides moriutii (Lepidoptera: Tineidae)

“…(Yang et al, 2007), 배추좀나방 역시 2령충 보다는 4령충에서 감수성 이 증가한 결과와 일치하였다 (Kim et al, 2006b). 하지만 이와 반대로 담배거세미나방, 파밤나방에서는 노숙화 될 수록 반수치사농도가 높아져 감수성이 줄어드는 결과를 나타내었다 (Kim et al, 2006a;Kim et al, 2008). 이러한 기주곤충의 령기에 따라 곤충병원성 선충의 병원성은 다 양하게 나타나는데 유충이 노숙화 될수록 자체 면역력이 증가되어 감수성이 감소하는 경우와 섭식량 증가, 자연개 구 즉, 입, 숨구멍, 항문, 체절과 체절 사이 등 물리적 침 입 공간이 많아져 감수성이 증가 될 수 있다 (Fuxa et al, 1988).…”