Effect of Syzygium aromaticum cloves on larvae of the rhinoceros beetle, Oryctes agamemnon (Coleoptera: Scarabaeidae)

The susceptibility of rhinoceros beetle larvae, Oryctes agamemnon, to different concentrations of Syzygium aromaticum cloves was studied under laboratory conditions. Two forms of cloves were applied, first as finely powdered flower buds and later as an essential oil. The clove powder concentrations used against the larvae were 1, 3, 5, 7 and 9%, and the clove essential oil (CEO) was used at concentrations of 1, 2, 3, 4 and 5 %. The highest (68.5 %) and lowest (2 %) larval mortality were caused by 9% and 1% clove flower bud powder (CFBP), respectively. However, the CEO was more effective against the larvae of O. agamemnon than the powder. Mortalities ranged from 12.5 to 87.9 % at oil concentrations of 1 and 5 %, respectively. The results also showed that the two forms of cloves persist in the treated soil for 7 to 8 days. Additionally, the clove oil and powder have a residual effect in treated soil that provides sustainable protection for date palms against root borers. Accordingly, it was concluded that cloves in either powder or essential oil form are very promising for controlling Oryctes larvae. These results indicate that clove flower buds and essential oils are desirable tools for crop protection in the future, promoting environmentally friendly pest control strategies.