Response of Nasutitermes Luzonicus and Macrotermes Gilvus (Isoptera: Termitidae) to Allamanda Cathartica (Apocynaceae) Leaf Extract Under Laboratory Conditions

Termites eat cellulose-based materials and become economically important pests due to substantial mutilation on anthropogenic structures. It is imperative, therefore, to look for economical, natural, and effective solution without environmental and human hazards of chemical termiticides. Allamanda cathartica possesses toxic iridoid lactones, such as allamandin, plumieride, plumericin, and isoplumiricin, which creates a possible termite control. A. cathartica leaf decoction, crude leaf extract, 40% and 80% methanolic leaf extract (% v/v), distilled water (negative control) and Solignum® (standard check) were sprayed on one hundred soldiers and workers of Nasutitermes luzonicus and Macrotermes gilvus. The experiment was arranged in a Completely Randomized Design (CRD) with three replications for each treatment. Results showed that the experimental treatments exhibited termiticidal activity against N. luzonicus and M. gilvus. Across castes, significant differences (P < 0.05) on mean mortality of leaf extracts were observed. In terms of N. luzonicus, the maximum mean mortality was recorded by the 80% methanolic leaf extract which registered 96.67% ± 2.03% in soldiers and 100.00% in workers, with an overall mean mortality of 98.34%. In terms of M. gilvus, it is the 40% and 80% methanolic leaf extract which measured the maximum mean mortality in soldiers (60.00 ± 0.58% and 91.00 ± 7.09%) and workers (87.00 ± 2.08% and 85.33 ± 3.48%) and made an overall mean mortality of 88.17%. Generally, the greatest potency was delivered by the 80% methanolic leaf extract which displayed comparable effects with standard check and can be used as a biotermiticide for pest control and management.