Yield loss quantification and assessment of economic injury level for the anthophagous generation of the European grapevine moth<b><i>Lobesia botrana</i></b>Den. et Schiff. (Lepidoptera: Tortricidae)

Abstract

Abstract Until now, no attempts have been made to assess systematically the damage to vine from the first (anthophagous) generation of the European grapevine moth Lobesia botrana Den. et Schiff. (Lepidoptera: Tortricidae). No standards for intervention have been established; consequently, control measures are undertaken arbitrarily and regardless of economic costs. In the region of East Attiki in Greece, where the wine variety 'Savvatiano' is grown, the larvae of the first generation of the moth may destroy not only blossoms, but also newly set berries. Damage simulation experiments, carried out in this area to study the variety's response to injury of blossoms and berries, showed that it has the capacity to compensate completely for the damage to the blossoms by means of a proportionate decrease in shedding of natural blossoms. However, it cannot make up for damage to young berries. The yield loss from the first generation larvae was calculated over the years 1995 – 1999 and economic injury levels (EILs) were assessed The loss of yield, in this case exclusively from injury to berries, was found to be, on average, 15.5 g/grape, 75.5 kg/ha or 3.6%. The EIL, measured in units of injury and numbers of pest specimens using simple empirical equations incorporating dynamic biological and economic factors, fluctuated only slightly during the 5 years of the survey, averaging 7.7 larval 'nests'/inflorescence or 3.6 larvae/inflorescence. Although the EIL is specific to the Savvatiano variety and the East Attiki region, the methodology employed could have a broader application. Keywords: GrapevineLobesia botranayield losseconomic injury levelinfestationdamagedamage simulationdamage responseinjury compensationinjury unit Acknowledgements The author would like to thank to Dr Th. Broumas director of the Department of Entomology and Agricultural Zoology of the Benaki Phytopathological Institute for reviewing the manuscript, Ms Vassiliki Kapothanassi, Technical assistant of the Laboratory of Agricultural Entomology for her contribution to the examination of the samples and the company Cambas SA for kindly granting the use of the vineyard over a number of years.