Assessment of biological and phenological aspects of broomrape (Orobanche nana) in parasitism with Almond (Prunus dulcis)

The biology and phenology of broomrape (Orobanche nana) on Almond (Prunus dulcis cv. Mamaei) was studied during the growth season in Shahrekord city of Iran in 2004. Twenty trees which were infested by broomrape, were selected. Results indicated that almonds need 2120.5 growth degree days (GDD) to complete phenological stages from flowering to fruit ripening. Based on the cardinal temperature of broomrape (9.5°C), the parasite weed needs 209, 1125.5, 1414.5 and 961 GDD for completion of seed germination, stem emergence, flowering and seeding stages, respectively. Maximum seed germination occurred at the depth of 18 cm. Maximum root infection was observed at the depth of 9 to 12 cm. The highest infection to this parasite plant was recorded on roots with 9 to 11.9 mm diameter.