Raoiella indica Hirst
Common name: Red palm mite (RPM).
Taxonomic placing: Acari, Prostigmata, Tetranychoidea, Tenuipalpidae.
Morphology: The females are about 0.3 mm in length, bright red, with spatulate dorsal setae whose rounded tips appear to bear liquid drops.
Distribution: Middle East, Iran, Pakistan, South-East Asia, Africa, and since 2004 also in the Caribbean, Central and South America, and Florida.
Host plants: More than 60 different species, especially palms, banana, plantain (banana cultivars whose fruits are cooked before eaten) and areca nut (Areca catechu L.). Other hosts include members in the families Heliconiaceae, Zingiberaceae, Strelitziaceae and Cycadaceae.
Life history: RPM raises a generation in 3-4 weeks. The eggs (about 45/mated female at 27ºC, about half if unmated) are attached to the underside of leaves, near the midrib or in depressions, where they feed. Coconut cultivars with higher nitrogen and crude protein levels carried larger pest populations. On date palms the mites may hide under the empty shields of Parlatoria blanchardi. RPM populations increase under hot and dry conditions, decrease in cool and wet weather. The calculated Threshold of development is 14.8ºC, and about 208 day degrees are required to complete a generation. Average longevity is 7-10 weeks. Local dispersal is mainly by winds, whereas long-distance dispersal is by infested plants.
Economic importance: RPM feeding causes leaf yellowing, chlorotic patches and necrosis, and the loss of flowers and small fruits, resulting in greatly reduced yields. Young plants are severely affected and heavy infestations can cause their death. Coconut production may drop by >50-70; similar losses were reported for bananas and plantain. The value of ornamental palms is much affected by mite damage.
The invasion of RPM into the Americas in the early 2000’s is regarded as a serious threat to coconut and banana there.
Chemical control: Most commonly used acaricides control the mite, reducing its populations by more than 95% within 7 days after application. However, their use may not be practical due to the large size of many hosts, like palms.
Biological control: Several Phytoseiidae attack R. indica in different parts of the world, the most promising being Amblyseius largoensis (Muma). Important predators found in the Eastern Hemisphere include other mites, the thrips Aleurodothrips fasciapennis (Franklin), Coccinellidae (especially Stethorus spp.) and lacewings. Cheletogenes ornatus is an important enemy in Egypt.
Carrillo, D., Frank, J.H., Rodrigue, J.C.V. and Peña, J.E. 2012. A review of the natural enemies of the red palm mite, Raoiella indica (Acari: Tenuipalpidae). Experimental and Applied Acarology 57: 247-360.
Correa-Méndez, A. (and 6 co-authors) 2018. Control químico del ácaro rojo de las palmas Raoiella indica Hirst (Acari: Tenuipalpidae). Ecosistemas y Recursos Agropecuaria 5: 319-326.
Fidelis, E.G., Reis, M.A.S., Negrini, M. and Navia D. 2019. Life table parameters of the red palm mite Raoiella indica (Acari: Tenuipalpidae) at various temperatures and for sexual and asexual reproduction. Experimental and Applied Acarology 78: 535–546.
Gerson, U., Venezian, A. and Blumberg, D. 1983. Phytophagous mites on date palms in Israel. Fruits 38: 133–135.
Jayaraj, J., Natarajan, K. and Ramasubramanian, G.V. 1991. Control of Raoiella indica Hirst. (Tenuipalpidae: Acari) on coconut with pesticides. Indian Coconut Journal (Cochin), 22: 7-9.
Lima, M.R., Rodriguez. H., Gonzalez, A.I. and Gonzalez, M. 2011. Management strategy of Raoiella indica Hirst (Acari: Tenuipalpidae) in Cuba. Zoosymposia 6:152–159.
Melo, J.W.S. (and 20 co-authors). 2018. The invasive red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae) in Brazil: range extension, and arrival into the most threatened area, the Norteast Region. International Journal of Acarology 44: 146-149.
Mesbah, A.E. and Omar, N.A. 2014. Predator-prey preferences and life-table-parameters of Cheletogenes ornatus (Canestrini & Fanzago) to red palm mite Raoiella indica Hirst and date scale-Insect Parlatoria blanchardii (Targ.). Acarines 8:19-23.
Peña, J.E., Rodrigues, J.C., Roda, A., Carrillo, D., and Osborne, L. 2009. Predator-prey dynamics and strategies for control of the red palm mite (Raoiella indica) (Acari: Tenuipalpidae) in areas of invasion in the Neotropics. IOBC/WPRS Bulletin 50: 69-79.
Sarkar, P.K. and Somchoudhury, A.K. 1988. Evaluation of some pesticides against Raoiella indica Hirst on coconut palm in West Bengal. Pesticides 22: 21-22.
Sarkar, P.K. and Somchoudhury, A.K. 1989. Interrelationship between plant characters and incidence of Raoiella indica Hirst. on coconut. Indian Journal of Entomology 51: 45-50.
Zaher, M.A., Wafa, A.K. and Yousef, A.A. 1969. Biological studies on Raoiella indica Hirst and Phyllotetranychus aegyptiacus Sayed infesting date palm trees in U. A. R. (Acarina: Tenuipalpidae). Z Angew Entomol 63: 406–411.