Eiphosoma laphygmae, a Classical Solution for the Biocontrol of the Fall Armyworm, Spodoptera frugiperda?

The fall armyworm. Spodoptera frugiperda (J E Smith, 1757) is an invasive Lepidoptera
and one of the most damaging cereal pests in the tropics, having arrived in Africa
in 2016, spreading through the continent, then on to Asia. Current control methods
rely on insecticides whereas biological control might offer a more sustainable solution.
The parasitoids, Eiphosoma laphygmae and E. vitticole (Hymenoptera: Ichneumonidae),
previously considered as synonyms, are potential classical biological control
agents, yet knowledge on their biology needs to be collated and specificity assessments
conducted. We aimed to assess existing knowledge on biology, identify their
natural distribution, collate reported parasitism rates from field studies and determine
which other parasitoids co-occur with them. We conducted a systematic literature review
using the keyword “Eiphosoma” on 11.11.2019 in Web of Science, Agricola, CABAbstracts,
and Food Science and Technology Abstracts. On 12.11.2019, we searched
using the search string (“Eiphosoma vitticole” OR “Eiphosoma laphygmae”) in full text in
googlescholar. We had 121 initial hits. We then excluded papers from outside the topic
areas and three for which we had no access, retaining 44 papers in English, Portuguese
and Spanish.
Reports on the natural distribution of E. laphygmae were restricted to the American
tropics with the most northerly record from Northern Mexico and the most southerly
from the state of Sao Paulo, Brazil. In fields where E. laphygmae naturally occurred, it
was the second most important contributor to the mortality of the fall armyworm, after
Chelonus insularis, another hymenopteran parasitoid. On average, E. laphygmae parasitized 4.3 % of fall armyworm in field studies. The highest parasitism rates were observed in Costa Rica (13 %) and Minas Gerais Brazil (14.5 %). E. laphygmae appeared
to establish better in more diverse systems with weeds. Given that it is assumed to
be synovigenic, it is dependent on protein and nectar from wild flowers for egg production.
As African farming systems often have high diversity, this may favour the
establishment of E. laphygmae if eventually introduced as a classical biological control
agent.