Date palms, Phoenix dactylifera (L.), are considered as one of the most economically important fruit trees in Iran that covers 199000 ha and its annual production is 1.01 million tons. These trees and their fruits are subjected to infestation by many serous insect pests for instance date longhorn beetle, Jubusea hammerschmidti (Reiche, 1877) (Coloptera: Cerambycidae).This species is particularly pest of Palmaceae. Damage of this pest is limited to tree trunk. Larvae feed on the basses of frond, and create a hole in trunk of date palm. Old and dried leaves are pruned but base of petioles remain on trunk and are dried. These petioles are an infestation site for oviposition and activity of pest. Effect of date palm petiole pruning in population decline of date palm longhorn beetles was evaluated in Tangestan region in Bushehr province. 3 date palm orchards with petioles pruning and 3 date palm orchards without petioles pruning were selected for this purpose. 10 trees selected from each orchard randomly and active bores of date palm longhorn beetle were counted and recorded. Data was analyzed with SPSS software and means were compared with T test. The results showed that mean (± SE) of active bores of date palm longhorn beetle in orchards with and without petioles pruning was 0.85 ± 0.189 and 4.23 ± 0.642 respectively and there is a significant difference between them. So petiole pruning of date palm is effective in population decline of Jubusea hammerschmidti (Reiche). To reduce the damage of this pest, petioles pruning of date palm were recommended.