Preference of Rhynchophorus ferrugineus to date palm cultivars: Olfactometer assays

Date palm, Phoenix dactylifera L is the most important crop of the Arabian Peninsula. The Food and Agriculture Organization of the UN has designated red palm weevil Rhynchophorus ferrugineus (Coleoptera : Curculionidae) as a category-1 pest of date palm in the Middle East. The Kingdom of Saudi Arabia is reported to have over 400 date palm cultivars and produces over a million tones of dates annually.

With an estimated three million date palms the Al-Ahsa region in the Eastern province of Saudi Arabia is the largest date palm oasis in the Kingdom. We assessed the degree of preference by RPW in seven major date palm cultivars of Al-Ahsa viz. Khalas, Sheshi, Reziz, Khasab, Hatmi, Shahal and Gaar by determining the attraction of RPW to fresh palm volatiles emitted from date palm frond tissue through four-arm choice olfactometer assays.

Results revealed that the weevil was most attracted to the palm tissue volatiles of the cultivar Khalas which was statistically similar to the cultivars Reziz, Sheshi and Hatmi. The cultivars Khasab, Shahal and Gaar exhibited high degree of non-preference (antixenosis). Since over 50% of the area in the Al-Ahsa oasis is under the cultivar Khalas with plantations in the susceptible age of less than 20 years, RPW is likely to pose a major challenge to date farmers of the region in the years to come.