Insect diversity on rambutan (Nephelium lappaceum L.) – A tropical fruit tree of East Asia

Rambutan (Nephelium lappaceum L.) is a tropical fruit from the Sapindaceae family and an emerging popular fruit tree in India and other Southeast Asian countries. Insect pest infestation in rambutan has not been systematically documented earlier. As the area of rambutan planting is increasing, a systematic documentation of arthropod diversity associated with rambutan is necessary. This study identified and documented 32 insect pest species on rambutan trees across Kerala, India. Sucking pests were predominant in rambutan followed by leaf and inflorescence caterpillars and beetles. The fluctuation of insect infestation on rambutan with respect to abiotic factors was studied for one year from November 2022 to November 2023. Pest infestations were highest from March 2023 to May 2023 during the flowering and fruit-setting stages. The pest incidence in rambutan showed a positive correlation with temperature and a negative correlation with rainfall and relative humidity. A study was conducted during the flowering season of rambutan to document pollinators. Ten pollinator species were observed on rambutan, with the stingless bee Tetragonula travancorica (Shanas and Faseeh) being the most frequent and abundant flower visitor. Understanding insect diversity can help farmers more effectively anticipate and manage sporadic pest outbreaks.