Sammanfattning

Over two decades ago, an intercropping strategy was developed that received critical acclaim for synergizing food security with ecosystem resilience in smallholder farming. The push-pull strategy reportedly suppresses lepidopteran pests in maize through a combination of a repellent intercrop (push), commonly Desmodium spp., and an attractive, border crop (pull). Key in the system is the intercrop's constitutive release of volatile terpenoids that repel herbivores. However, the earlier described volatile terpenoids were not detectable in the headspace of Desmodium, and only minimally upon herbivory. This was independent of soil type, microbiome composition, and whether collections were made in the laboratory or in the field. Furthermore, in oviposition choice tests in a wind tunnel, maize with or without an odor background of Desmodium was equally attractive for the invasive pest Spodoptera frugiperda. In search of an alternative mechanism, we found that neonate larvae strongly preferred Desmodium over maize. However, their development stagnated and no larva survived. In addition, older larvae were frequently seen impaled and immobilized by the dense network of silica-fortified, non-glandular trichomes. Thus, our data suggest that Desmodium may act through intercepting and decimating dispersing larval offspring rather than adult deterrence. As a hallmark of sustainable pest control, maize-Desmodium push-pull intercropping has inspired countless efforts to emulate stimulo-deterrent diversion in other cropping systems. However, detailed knowledge of the actual mechanisms is required to rationally improve the strategy, and translate the concept to other cropping systems.

Nyckelord

push-pull intercropping; integrated pest management; Spodoptera frugiperda; fall army worm; Desmodium; mechanical defence; Maize; Spodoptera littoralis

Publicerad i

eLife
2024, Volym: 13, artikelnummer: e88695
Utgivare: eLIFE SCIENCES PUBL LTD

SLU författare

• Erdei, Anna Laura

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    
  • Hungarian Centre for Agricultural Research

• Bella David, Aneth

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    
  • University of Dar es Salaam

• Savvidou, Eleni

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    
  • Πανεπιστήμιο Θεσσαλίας

• Dzemedzionaite, Vaida

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Shankarkumar, Advaith Chakravarthy

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

• Dekker, Teun

  • Institutionen för växtskyddsbiologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Jordbruksvetenskap


Publikationens identifierare

DOI: https://doi.org/10.7554/eLife.88695

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/129403