Temporal patterns of <i>Oryctes monoceros</i> (Olivier) (Coleoptera: Scarabaeidae: Dynastinae) in oil palm replanting: A study across three cycles

The African oil palm Elaeis guineensis Jacquin has a commercial life span between 20–30 years after which replanting is advised. Although a sound agronomic decision, planted seedlings are at risk of potential attack and damage by adult Oryctes . While it is known that adult population – in infested re‐planted palm plantation – increases with time, specific information on their population trend is limited. Hence the population of the adult Oryctes monoceros pest in 3 years of replanting (YOR) – 2018, 2020, and 2022 – in Ubima Oil Palm Plantation, Rivers State, Nigeria, was monitored, for at least twenty‐seven months, after the planting end month (PEM). Results showed progressive increase in adult population that peaked between 24 to 26 months, then began to decline. The small standard error of the mean (SEM) obtained, showed the sample mean as a precise estimate of the population mean. The one‐way analysis of variance (ANOVA) showed a highly statistical significance across the study months. Similarly, the nested ANOVA showed that variation in O. monoceros population was statistically significant across all tested variables between the three YOR. The study showed that the developmental continuity of O. monoceros is dependent on the trunk and its speed of decay. Furthermore, a second replanting phase will reach peak population faster and will surfer more damage than a first replanting phase. This study provides plantation owners and managers with information on how long the challenge of O. monoceros will likely last, as well as how best to plan replanting activities across multiple years.