Survey and Relative Abundance of Insects (Insecta) Excluding Lepidoptera from Sixteen Commercial Date Palm Orchards using Light Traps at Riyadh Province, Saudi Arabia

Abstract

Date palm (Phoenix dactylifera L.) is one of the oldest fruit crops of the world having been cultivated for many centuries in North Africa and the Middle East. In Saudi Arabia commercial date palm production is an important industry. Insects, excluding the Lepidoptera, were sampled with Robinson-type light traps placed in 16 date palm commercial orchards in the Al-Kharj region, Riyadh Province, Saudi Arabia, for 12 months from June 2007 to May 2008. No insecticide treatments or manure fertilizer applications were made in the orchards during operation of the traps. A total of 44 485 insects representing nine orders (Orthoptera, Blattodea, Dermaptera, Hemiptera, Mantodea, Neuroptera, Coleoptera, Hymenoptera and Diptera) and at least 50 different taxa were counted and identified. Most of the insects were trapped during a period extending from mid-Spring (April) to early autumn (September). The highest numbers were trapped during July and August (87 % of the total). Two orders, Coleoptera and Diptera represented 97 % of all insects trapped. Beetles comprised 87.83 % of the total insects trapped with scarabs composing 73 % of this percentage. The fruit stalk borer Oryctes elegans comprised 58 % of that total. This species was exceptionally abundant in one of the orchards in August. Dipterans comprising 10 % of the total (4 701 individuals), was the only other order attracted in relatively large numbers to the light traps. Most of these flies were trapped during August. The sericine scarab Maladera insanabilis previously not known from date palm orchards of Saudi Arabia may be a potential new pest.