Biology and thermal requirements of the almond seed wasp, Eurytoma amygdali (Hym.: Eurytomidae) in Zarinshar, Isfahan

The almond seed wasp, Eurytoma amygdali (Hym.: Eurytomidae) is a key pest of almond in Iran. The pest may destroy, in some cases, up to 90% of the almond seeds. Because of the pest importance and the lack of adequate information on its phenology in Isfahan, this study was carried out to investigate the phenology of the almond seed wasp. About 30% of the larvae showed prolonged diapause in the Zarainshahr region in 2015. The lower temperature threshold of the pest was estimated 7.214 °C and thermal constant for pupal stage under the laboratory conditions was 237.03±2.93 degree-days. Phenological study in Zarinshar showed that termination of pest pupation occurred in 30.3.2015 (by about 139 degree-days). Adult peak emergence occurred on 25.4.2015 (by about 358 degree-days). Peak of the egg laying was observed in 1.5.2015 (by 313.5 degree-days). Suitable fruit size for egg laying was estimated to be about 1.5×2.5 - 2.4×3.5 cm.