Rhinoceros beetles and its Management in Coconut Cultivation

                    Coconut tree, Cocos nucifera, a palm tree, belonging to family Arecaceae. Main product of it is  fruit which has its own culinary importance, whereas its oil has industrially, pharmaceutically important.  As the crop attracts many pest and diseases,  rhinoceros beetles is one such important  pest of  economic importance.

Biology of Oryctes rhinoceros

                            Coconut rhinoceros beetles scientifically known as Oryctes rinoceros belongs to family's Scaraebidae. Beetles rightly called as Elephant or Hercules Beetles because of the fact that,  they  are capable of carrying  or lift the weight equal to 850 times of its body weight. These are  giant beetles  which can can grow up the length of 15 cm. Adults are brown to blackish in color with characteristics horn on head or pronotum and  another is at middle of the thorax. Though they look scary, are harmless to human being as they cannot sting or bite. These horns are used to fight with other beetles to protect its territory, food resources and for female beetles. Horns also help to navigate them in cavities, dense forests, litters and debris. Adults are nocturnal in habitat and they  feed on nectars, plant saps, fruits. Adults have thickened elytra and membranous second pair of wings underneath.

                          Grubs are 'C' shaped, whitish or sometimes off white with red colored head. Immediately on hatching grubs start feeding on decaying organic matters, wooden materials, soils rich in organic matters and other debris.

Adult Female on mating lays the eggs up to 50 in numbers. Eggs are laid just beneth the soils, under trashes and litters.

Economic damage by Oryctes rhinoceros

               Rhinoceros beetles are majorly affect palm trees like coconut and others. There is a chance of insect of different stages of insect in same palm. Beetles also reside in stems of mango, bread fruit. Though they affect healthy tree, they prefer sick or affected or dying trees. Adult bore cavity on crown at the growing point of the palm.  Adult may feed on leaves by cutting affecting overall health.  of the tree.  Affected trees look sick,  leaves has sharply cut edges.  

Management of Rhinoceros Beetles in coconut

There are different ways with which menace of rhinoceros beetles can be managed. Culturally grower can keep the orchard clean, free from debris, free from sick and dead tree which are potential breeding points.

Mechanically, the hand picking of beetles and grubs are found effective in minimizing the beetles populations.

Use of pheromone traps Pheromones traps contains Ethyl-4 methyl octanoate has been found very effective in attracting and tracking Oryctes beetles in considerably high in number. Ethyl-4 methyl octanoate is a chemical signal used by beetles to indicate their presence. Pheromones are placed in containers especially in bucket, maybe placed in tree branches or partially bury in ground. Traps are useful in and very is effective in controlling the beetles.

Use of fungus Metarhizium anisophilae: Metarhizium anisophilae is a entomopathogenic fungus which causes diseases in insects like Oryctes Rhinocerous especially in grub stage. These are soil inhabiting fungi which easily target grubs hidden under soil or trashes when soil are drenched. Foliar spray also have been found effective to infect and kill adult stage.