Data from: Natural vegetation benefits synergistic control of the three main insect and pathogen pests of fruit crop in southern Africa

1. Most studies of the potential for natural habitat to improve
agricultural productivity have been conducted in transformed, temperate
regions, but little is known of the importance of agroecosystem services
in biodiverse developing countries. 2. Natural vegetation may promote the
density and/or diversity of natural enemies of crop pests, but the
strength of the effect varies, and few studies directly measure concurrent
impacts on pest density. Considering multiple pest species within the same
agroecosystem may help explain why some pests are more affected than
others by landscape complexity. Here, we investigated multiple pest
species (three species of Tephritidae fruit fly, leaf galling flies and
pathogenic fungi Fusarium spp.) and their enemies in cultivated mango
Mangifera indica, in north-eastern South Africa. 3. The density of
generalist Tephritidae fruit flies increased with distance from natural
vegetation during harvesting months, and predation rate of pupae sharply
decreased from ~50% at the edge with natural vegetation to 0% at 250 m
into the crop. Parasitism rates of the cryptic, gall-forming fly increased
with proximity to natural vegetation, but pest density was unrelated to
distance from natural vegetation. Incidence of the fungal pathogen disease
increased with distance from natural vegetation, possibly due to decreased
predation of commensal mites. 4. Although the relationship with distance
to natural vegetation was significant for all species considered, the
strength of this relationship varied across pest species and type of
natural enemy studied, suggesting the benefits of natural vegetation
depend on each natural enemy species' ability to disperse into the
agricultural environment. 5. Synthesis and applications. Our results
suggest that natural vegetation is a net source of natural enemies in a
region of South Africa that still contains much of its natural
biodiversity. However, the decline in natural enemies, and increase in
pests, with distance from natural habitat indicates that this biocontrol
is limited by natural enemy dispersal. In landscapes like these that are
still dominated by natural habitat, conservation biocontrol can still be
improved by management aimed at providing corridors of key plants and
habitat elements into the crops, to facilitate natural enemy dispersal.