USING Rhabditis blumi SUDHAUS AS BIOLOGICAL AGENTS TO CONTROL THE PALP BORER, ARABIAN RHINOCEROS BEETLE, Oryctes agamemnon arabicus

This study was aimed to use pathogenicity of entomopathogenic nematodes (EPN) Rhabditis blumi Sudhaus (Nematoda: Rhabditida) against palm borer Arabian Rhinoceros Beetle (ARB), Oryctes agamemnon arabicus was evaluated in the lab. And date palm orchards during 2015 - 2017. In the lab tests, EPN was used against the larvae and adults as a direct spray and as treated food (pieces of fresh tissue of the frond bases) at a rate of 0, 500, 1000, 1500 Infective Juveniles (IJs) per mL of R. blumi. Results indicated that EPN caused 89%, 61% and 25%, 20% mortality when used as a direct spray and as treated food on larvae and adults of ARB, respectively. Results of field experiments showed that injection of 50 mL per palm tree with a concentration of 1500 IJs/mL of R. blumi inflected about 45.5% mortality in ARB larvae infesting the tree. Meanwhile, the Population density of ARB larvae reduced to 45.8%, 59.6% during the first and second year of treated date palm trees by injection method respectively. The results of this investigation illustrate the possibility of using EPN R. blumi as a biocontrol agent for managing borers in date palm orchards under field conditions.

Evaluating the virulence of Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) and Beauveria bassiana (Ascomycota: Hypocreales) isolates to Arabian rhinoceros beetle, Oryctes agamemnon arabicus

Virulence of entomopathogenic fungi <em>Metarhizium anisopliae</em> and <em>Beauveria bassiana</em> were tested against Arabian Rhinoceros Beetle, <em>Oryctes agamemnon arabicus</em> larvae. Four concentrations (1×10⁵, 1×10⁷, 1×10⁹ and 1×10¹¹ conidia/mL^–1) of two locally isolated entomopathogenic fungi spore suspensions were used in this study via larval direct spraying. Results revealed that both isolates can cause high mortality rate reaching 100% after 29 days. However, <em>Beauveria bassiana</em> scored higher mortality rate in short time especially at the concentration of 1×10¹¹ conidia/ mL^–1 with lethal time (LT)₅₀ 12.75 and LT₉₀ 20.00; while, <em>Metarhizium anisopliae</em> caused the higher percentage of malformed adults. Moreover, both isolates affected insect’s life cycle particularly in the pupal stage which was reduced remarkably by almost 50% in comparison with the control treatment.