Acarological diversity on blackberry crop and neighbouring vegetation in Southwestern Portugal

Abstract: Natural vegetation management can be an important component of conservation biological control strategies and its interest as potential reservoir of beneficial organisms is increasing in integrated pest management. Acarological surveys on blackberry plantations (open field and greenhouse) and nearby weeds were carried out fortnightly from March to June 2011, in order to study species diversity and population interaction. The research was conducted in Odemira (Southwestern Portugal) and was performed on three blackberry cultivars: ‘Apache’, ‘Ouachita’ and ‘Karaka Black’. The importance of natural vegetation on crop mite populations and its potential contribution to enhance biological control of mite pests were evaluated.The redberry mite Acalitus essigi (Hassan) was the most noxious mite, causing severe damage in protected crop. The late maturing Ouachita cultivar was the most attacked by this eriophyid mite. The most common predacious mites on blackberries were the stigmaeid Agistemus longisetus Gonzalez and the phytoseiids Amblyseius stipulatus Athias-Henriot and Typhlodromus recki Wainstein. These predacious mite species were also the predominant mites on weeds, as well as other mites that may also contribute for biological control as they constitute alternative prey for predators, in particular Orthotydeus californicus (Banks).The results obtained showed the influence of the neighbouring vegetation on the occurrence of predacious mites on blackberry plantations. From acarological point of view, safeguarding the competition relatively to some vegetal species, spontaneous vegetation can be an important component of conservation biological control in blackberry crop, because host weeds of mites are mostly repositories of predacious species.