**4.2 Coleopteran pests**

#### *4.2.1 Rhinoceros beetle,* Oryctes rhinoceros *L. (Scarabaeidae)*

It is a standard pest of the many palms including coconut, oil palm, edible seed and palmyra palms all through the states of India. It became a major pest in all the Indian states that grow oil palm [31]. It's found throughout South-East Asia and plenty of oil palm-growing countries. Pest incidence is found throughout the year but its incidence where adult emergence is at its peak during South-West Monsoon (June to September). This means that pest emergence synchronises with the monsoon showers. Infestation is severe in plantations where field hygiene and sanitation are neglected. Palmyrah palm (*Borasses flabellifer*), coconut, arecanut are collateral hosts of this pest (**Figure 8**) [24, 32, 33].

This Rhonoceros beetle was found migrated from other palms such as coconut and palmyra during the initial periods of crop establishment. But within the recent period, it's found to reject the oil palm. This is often particularly seen when coconut plants are adjacent to these palms. The presence of more lignin at the place of feeding (leaf petiole) in oil palm compared to leaf tips within the case of other Arecaceae palms is that the prime reason for low pest incidence of the pest [34]. This also indicates the pest preference for a specific place of the crop. Costa Rican material, Deli X Ghana is found to be the smallest amount at risk of scarabaeid beetle attack followed by Deli X Nigerian cross. The Malaysian variety Gutherie is found more vulnerable to the beetle followed by Palode material [27].

*Integrated Pest Management (IPM) in Oil Palm,* Elaeis guineensis *Jacq. DOI: http://dx.doi.org/10.5772/intechopen.108580*

**Figure 8.** *A. Life cycle of Rhinoceros Beetle; B. Symptoms of Rhinoceros Beetle infestation on oil palm.*

#### *4.2.1.1 Biology and nature of damage*

The oval, white eggs are placed at a depth of 5–10 cm in the surface of decomposing organic waste. The earliest stages of the beetle typically occur in manure pits, compost piles, rotting palm logs and stumps, decomposing organic materials like animal dung, and manure pits. Additionally, the oil palm leaf axils, decaying inflorescences, and mounds of mesocarp on the plantation are all places where the beetles can breed [35, 36]. A female lays between 100 and 150 eggs, which take 8–18 days to hatch. Once they do, the grubs begin to feed on the decomposing materials. The larvae endure three instars and reach maturity in 100–180 days depending on the conditions. The beetle pupates in a deep chamber at a depth of around 30 cm, and it emerges after 10–25 days. They remain in the pupal stage for another 10–20 days. After 20–60 days, they begin to lay eggs. In the dark hours, beetles are busy and drawn to sources of light. A grownup can live for more than 200 days. Typically, one generation is finished each year. When the spear cluster is closed, adult beetles penetrate into the palms at the base to eat the sap and delicate sections of the leaves. The beetles enter the spear cluster's inner petiole through its outermost petiole, causing a hole that will remain there forever. The frequent symptoms include a hole in the petiole and a wedgeshaped gap in the leaf profile. Compared to adult palms, young palms show much more severe damage near the bottom of the spears. Expanded fronds may break off or become truncated, or the damaged spindle may collapse. Even before anthesis, while the inflorescences are still inside the spathe, adult rhinoceros beetles have been observed digging and devouring the male and female inflorescences [37]. Beetles can be identified by their entry holes because they leave behind chewed-up fibrous fibres [19]. Because of the infiltration of fungi and bacteria through the injuries the insect caused to the palm's internal organs, secondary rotting of the bud is typically observed. The red palm weevil's functional birthing sites are wounds formed on petioles and female inflorescences.

#### *4.2.1.2 Management*

An integrated pest management approach by incorporating mechanical, sanitation, chemical, and biological aspects is required to combat the pest menace. Identifying all potential pest breeding locations and keeping an eye on the beetle population on the palm's crown are crucial parts of pest management technology.


*Integrated Pest Management (IPM) in Oil Palm,* Elaeis guineensis *Jacq. DOI: http://dx.doi.org/10.5772/intechopen.108580*

## *4.2.2 Cockchafer beetles (root grub):* Apogonia/Adoretus *spp. (Scarabaeidae)*

Because grubs are visible throughout the year, preferably in the first two to few months after planting, the incidence of adults is seen during the start of monsoon season (**Figure 9**).
