101(1)_str13

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 101, No. 1 (2014), p. 91–100
DOI  10.13080/z-a.2014.101.013

Species ratio, spring emergence, population dynamics and damage of plum sawflies Hoplocampa minuta and H. flava in plum orchard

Rimantas TAMOŠIŪNAS, Alma VALIUŠKAITĖ, Elena SURVILIENĖ, Neringa RASIUKEVIČIŪTĖ

Abstract

An investigation of black plum sawfly (Hoplocampa minuta Christ, 1791) and yellow plum sawfly (Hoplocampa flava Linnaeus, 1761) populations using white sticky traps Rebell^®bianco was carried out in a plum orchard of Institute of Horticulture of Lithuanian Research Centre for Agriculture and Forestry from 2010 to 2012. A possibility to predict spring emergence of H. minuta and H. flava using temperature sum method, species ratio, main population parameters and relation between trap catches and infestation levels were investigated. H. minuta appeared to be more dominant in the complex of two plum sawfly species during the study overall, building up to 62% of individuals in comparison to H. flava and, considering various population parameters (emergence and flight dynamics, population density, sex ratio) being more significant contributor to fruit damage. Population density and flight dynamics were driving factors in determining potential damage to crop. Coincidence between mass flight and flowering periods was one of the major factors influencing fruit damage caused by plum sawflies. When mass flight coincided with flowering phase, vulnerable to sawfly attack of plum cv. ‘Stanley’, a high damage level of 27.8% was observed. When mass flight was strongly shifted towards the end of flowering, a relatively low damage of 7.0% was recorded. Based on the results of the correlation analysis, trap catch data could be reliably used to predict the magnitude of fruit damage level only when mass flight coincides with susceptible flowering phase. Further studies are needed to establish reliable damage thresholds for different plum cultivars. Temperature sum model to predict emergence of first plum sawfly adults was proposed. The model was based on soil temperature at 10 cm depth and two different starting dates to begin calculation. Temperature sums of 86 and 84 degree-days were calculated. Provisionary date at a temperature sum of 60 degree-days is proposed for trap placement in the orchards.

Key words: plum sawflies, population dynamics, temperature sum model, white sticky traps.

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