Eiphosoma laphygmae is likely to be the best classical biological control against the destructive armyworm pest

The autumn soldier (Spodoptera frugiperda). Credit: CABI

A review conducted by CABI scientist Dr. Marc Kenis, suggests that the parasitoid Eiphosoma laphygmae is likely to be America’s best classical biological control against the destructive fall pest.

Dr. Kenis, Head of Risk Analysis and Invasion Ecology, based at CABI’s Swiss center in Delémont, assessed the prospects and limitations of a classical biological control program for the fall armyworm (Spodoptera frugiperda) using parasitoid larvae, which are considered the most suitable natural enemies of the pest.

His findings are published in Journal of Economic Entomology.

The fall armyworm – native to tropical and subtropical America – is a highly destructive pest of more than 350 plant species, although it favors staple foods of millions, such as corn, rice and sorghum.

A previous review led by Drs. Kenis, published in Entomologia Generalis, provided a comprehensive study of the fall armyworm that includes details on its invasiveness, biology, ecology, and management. 57 scientists from 46 different institutions participated.

The paper emphasized that according to Eschen et al. (2021), the fall soldier causes an estimated annual yield loss of US$9.4 billion in Africa alone. He adds that the pest’s invasion of developing countries has a significant impact on household income and food security.

In the latest review, Dr. Kenis said the most important larval parasitoids in his native range are presented and discussed for their suitability as CBC agents, based on the following criteria: their incidence and levels of parasitism, specificity, climatic suitability and the absence of closely related species that parasitize the fall armyworm in the input area.

Other parasitoids examined were Aleiodes laphygmae, Archytas marmoratus, Campoletis spp. and Cotesia marginiventris.

Dr. Kennis said, “The ichneumonid Eiphosoma laphygmae Costa-Lima (Hymenoptera: Icheumonidae) is considered a likely candidate for introduction due to its distinctiveness and importance as a parasitoid of the parasite throughout most of its native range.

“The most common and important parasitoid of S. frugiperda in the Americas, Chelonus insularis Cresson (Hymenoptera: Braconidae), would likely contribute to S. frugiperda control if released into invaded areas. However, it is oligophagous and will certainly parasitize non-target species’.

He added that before introducing C. insularis, or any other parasitic species, the potential non-target effects should be assessed and the risks weighed against the benefits of improving natural control of this important pest.

Other CABI research into the fall armyworm mitigation effort has included a former Ph.D. student, Patrick Fallet, from the University of Neuchâtel and CABI in Switzerland, testing numerous nematode formulations applied to the corn borer. These have been shown to be just as effective as pesticide sprays.

Meanwhile, scientists from the MARA China-CABI Joint Biosecurity Laboratory and the MARA China-CABI European Laboratory are working to find viable and effective natural enemies for the fall army with 70 species identified in China alone.

These include 44 predators such as species of Pentatomidae, Lygaeidae, Anthocoridae, Nabidae, Coccinellidae, Reduviidae, Chrysopidae, Forficulidae, Formicidae and Vespidae. Bugs and beetles make up 68% of predators.

More information:
Marc Kenis, Prospects for classical biological control of Spodoptera frugiperda (Lepidoptera: Noctuidae) in invaded areas using parasitoids from the Americas, (2023). DOI: 10.1093/jee/toad029

Reference: Eiphosoma laphygmae likely to be best classical biological control against destructive fall armyworm pest (2023, March 8) Retrieved March 9, 2023 from https://phys.org/news/2023-03-eiphosoma- laphygmae-classical-biological-devastating. html

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