Invasion and expansion of exotic whiteflies (Hemiptera: Aleyrodidae) in India and their economic importance

Abstract

Exotic invasive whiteflies (Hemiptera: Aleyrodidae) in India cause direct and indirect yield losses in agriculture, horticulture and forestry crop plants. Around 25 years ago, the spiralling whitefly, Aleurodicus dispersus Russell invaded and established on many host plants including economically important crops in India. Recently, within a span of five years, seven whiteflies invaded India viz., solanum whitefly, Aleurothrixus trachoides (Back) reported to breed on 37 plant species; rugose spiraling whitefly (RSW), Aleurodicus rugioperculatus Martin found breeding on 40 host plants; nesting whiteflies, Paraleyrodes bondari Peracchi on 34 host plants and P. minei Ιaccarino infest about 25 host plants; legume feeding whitefly, Tetraleurodes acaciae (Quaintance) infesting 5 host plants; palm infesting whitefly, Aleurotrachelus atratus Hempel on 4 host plants and woolly whitefly, Aleurothrixus floccosus (Maskell) infesting guava. These invasive species are native to the Neotropical region, mostly from Central America and the Caribbean. Extensive spread along the coastal regions and gardens near the backwater of India is predicted owing to the favorable weather factors and availability of host plants. Species of exotic whiteflies with similar habits co-exist in more or less the same niche and have a similar pattern of growth and development. The intensity of infestation of RSW on coconut, banana and oil palm, the woolly whitefly on guava and the palm infesting whitefly and nesting whiteflies on coconut was severe. The exotic aphelinid parasitoid, Encarsia guadeloupae Viggiani (Hymenoptera: Aphelinidae), a predator Pseudomallada astur (Banks) (Neuroptera: Chrysopidae) and the entomopathogenic fungus, Isaria fumosorosea Wize (Hypocreales: Clavicipitaceae) play a major role in reducing the population of these invasives. The most insidious spread of these species in India is likely mediated by humans through the movement of infested seedlings and plant materials. Extensive surveys revealed that these species spread rapidly in the large geographical region of India mostly through transportation of infested seedlings. This study reports a major expansion of the geographic and host range and the patterns of co-occurrence, damage and economic impact of these exotic species in India and their natural enemies.