Integrated Control in Citrus Fruit Crops - IOBC-WPRS

Integrated Control in Citrus Fruit Crops
IOBC wprs Bulletin Vol. 29(3) 2006
Interactions between ground cover management, hedges and aphids in
lemon orchards
Pedro Rodrigues 1 , Fernando Albano Ilharco 2 , Elsa Borges da Silva 3 , José Carlos
Franco 3
1 Departamento Central de Marketing, Fitossanidade, Desenvolvimento e Aprovisionamento,
Agroquisa, Rua dos Navegantes 53, 2º Esq, 1200-732 Lisboa, Portugal,
2 Departamento de Protecção das Plantas, Estação Agronómica Nacional, Av. da República,
Nova Oeiras, 2784-505 Oeiras, Portugal,
3 Departamento de Protecção das Plantas e de Fitoecologia, Instituto Superior de Agronomia,
1349-017 Lisboa, Portugal
Abstract: An experiment was carried out in three lemon orchards of Mafra region, in Portugal,
aiming at studying the influence of ground cover management and hedges on the diversity and
abundance of aphids. Three different weed management systems were considered, i.e., ground cover
with resident vegetation, ground cover by sowing a selected seed mixture and herbicide application.
Samples were collected from January up to November 2003 on lemon trees, ground cover vegetation
and hedges both by visual observation and using “Vortis” arthropod suction sampler. A total of 1945
specimens were identified including 44 species from 28 different genera. Among these species, two
were reported for the first time in Portugal, Illinoia goldamaryae (Knowlton) and I. morrisoni
(Swain), and one in Continental Portugal, Atheroides serrulatus Haliday. From the identified aphid
species, all but Toxoptera auranti (Boyer de Fonscolombe) and Aphis spiraecola Patch are noneconomic
important for citrus crops in Continental Portugal. Aphis gossypii Glover was never
observed during the study. T. auranti was only detected on three plant species in ground cover
vegetation, i.e., Erodium moschatum, Senecio vulgaris and Trifolium campestre, and on Pittosporum
undulatum, in the hedges. The infestation level of aphids, mainly T. auranti, on lemon trees was low in
all three orchards. However, the average number of aphids was higher in plots where herbicide was
used compared with plots with ground cover vegetation. The possibility of exploring the interactions
between aphids and ecological infrastructures, such as ground cover vegetation and hedges, to
promote conservation biological control is discussed.