Determination of economic injury level of Ommatissus lybicus (Hemiptera: Tropiduchidae) on two commercial date cultivars in southern Iran

Dubas bug, Ommatissus lybicus Bergevin (1930), is one of the key pests of date palms in Iran, which drastically reduces the quality and quantity of dates produced. The Present study aimed to determine economic injury level of O. lybicus on two commercial date cultivars in three main date palm growing provinces of southern Iran. The economic injury level of dubas bug on date palm was estimated by Pedigo method. A date palm grove infested by dubas bug was chosen in Kerman (Bam), Fars (Farashband), and Bushehr (Tang-e Zard) provinces. The study was conducted in randomized complete block design with seven treatments replicated three times. Each experimental unit consisted of three identical trees in which the sampling was performed on the middle tree. We reached the intended densities of O. lybicus using natural and artificial infestation by using insecticides. The assessment was made based on the weekly recording the number of nymphs and honey droplets. In addition, the total weight of the harvested date was determined at harvesting. The results showed that EIL based on the number of nymphs/leaflet of date palm leaf on Zahedi cultivar were 1.06 and 0.34 nymphs for Farashband, respectively, and 0.28 and 0.88 nymphs for Tang-e Zard in studied years. The values for Bam on Mazafati cultivar in the three consecutive years of 2013, 2014 and, 2015 were 0.27, 0.25, and 0.10 nymphs, respectively.