EW4ZU9PT

2789

10 mars 2021 22:07

10 mars 2021 22:07

Soil fertility is tightly linked with herbivore pressure because it affects the nutritional status of host plants as well as the production of anti-herbivore defenses. This in turn can influence whether herbivores in different feeding guilds render plants more or less susceptible to one another. Thus, growers’ fertility management choices may impact herbivores through a variety of indirect channels. We examined relationships between soil fertility and interactions between phloem-feeding and leaf-chewing herbivores on broccoli (Brassica oleracea) plants in the greenhouse, taking advantage of natural variation in nitrogen (N) and phosphorus (P) in soils from 20 working organic vegetable farms. Next, we experimentally fertilized soil in a field trial with N and/or P to examine the consequences of these nutrients for growth of and interactions between specialist and generalist herbivores. Soils on our cooperating farms varied widely in P and N concentrations, with 40% exceeding recommended pre-plant N concentrations and 90% exceeding P recommendations. In single-herbivore infestations, augmenting N in the soil increased caterpillar (Pieris rapae) growth, augmented N and P additively enhanced generalist green peach aphid (Myzus persicae) colonization, and augmented P (but not N) increased specialist cabbage aphid (Brevicoryne brassicae) growth. In dual-guild herbivore infestations, caterpillars facilitated specialist cabbage aphid growth in the absence of fertilizer, but this pattern disappeared under augmented N, and reversed under augmented P. We found that a complex web of indirect effects linked soil fertility to herbivore performance, depending on the identity of the nutrients being altered, the ecological roles of responding herbivore species (i.e., specialist versus generalist), and indirect interactions between chewing and sucking herbivores. More generally, we highlight that successful use of fertility management to improve pest resistance requires careful consideration of herbivore feeding niches and herbivore-herbivore interactions.

None

• AB - Modalité bio
• FREDO biologie et travail du sol
• FREDO santé végétale
• GEO Etats-Unis
• interaction
• ravageurs

• dual-guild herbivory
• generalist herbivore
• herbivore resistance
• nitrogen
• organic agriculture
• phosphorus
• specialist herbivore

Basic and Applied Ecology

February 12, 2021

12 février 2021

10.1016/j.baae.2021.02.002 Le DOI est une URL unique de référencement d'une publication. Il est donc plus fiable et permanent qu'une URL classique

1439-1791 L’ISSN est un code de 8 chiffres servant à identifier les journaux, revues, magazines, périodiques de toute nature et sur tous supports, papier comme électronique.