ICAR-NBAIR Interventions in the successful management of invasive whiteflies of coconut and oil palm

The coconut and the oil palm are cultivated throughout the tropics where it is interwoven with the lives of the people and also provide a variety of products. The pest problem is one of the major constraints for achieving higher production and productivity in these palms especially the recent invasion of exotic invasive whiteflies. Since 2016, as many as six exotic whiteflies viz., rugose spiralling whitefly, Aleurodicus rugioperculatus during 2016, Bondar’s nesting whitefly, Paraleyrodes bondari and nesting whitefly, Paraleyrodes minei during 2018 and palm infesting whitefly, Aleurotrachelus atratus invaded in these palm plants in India. Extensive spread along the coastal regions and gardens near the backwater of India is predicted owing to the favourable weather factors and availability of host plants.

All these invasive species are highly polyphagous and have a host preference towards many economically important palm 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 most insidious spread of these species in India is likely mediated by humans through the movement of infested seedlings and plant materials. Nymphs and adults of these invasive whiteflies not only feed aggressively on leaf sap resulting in depletion of nutrients and water which leads to premature leaf drop and drying but also produce wax and excretes sticky honeydew which deposits on infested plants and inter-crops leading to the extreme growth of black sooty mould development which results in the reduction of photosynthetic efficiency in palms and marketability of produce. It has now become a regular pest of coconut and oil palm in India, warranting control measures to avoid crop losses.

Soon after the report of these invasive species in India, ICAR-National Bureau of Agricultural Insect Resources, Bengaluru, took proactive measures to contain the damage through regular monitoring, exploration of biocontrol agents, development of mass production protocol, demonstrations, sensitizing the growers through awareness programme, conservation practices and development of bio-intensive management strategies. Natural enemies of insect pests play a key role in reducing the levels of pest populations below those causing economic injury to crop plants. Both natural and applied biological control tactics are important in successful management of pest populations. Unlike annual crops, plantation crops provide the more congenial conditions for parasitoids, predators and entomopathogens for their growth and perpetuation.

ICAR-NBAIR developed the augmentation, re-distribution, mass production and conservation strategies of the potential parasitoids, Encarsia guadeloupae and E. cubensis and predator, Apertochrysa astur in coconut and oil palm through habitat manipulation and also identified & validated a potential entomopathogenic fungus, Isaria fumosorosea (ICAR-NBAIR Pfu-5) -“Shatpada Rugose Whitefly Kill” against these invasive whiteflies, which have been commercialized. Also standardization of mass production and formulation technology (talc, grain and oil-based) for potential strains with higher bio-efficacy, field persistence and longer shelf life. Under field conditions, a 72-78% reduction in the overall population of these whiteflies was observed in I. fumosorosea treated palm with two sprays at 15-day intervals. On the other hand, natural parasitism of E. guadeloupae on rugose spiralling whitefly to the extent of 65-82%, and 46-68% natural parasitism of E. cubensis on palm-infesting whitefly to 46-68 % was observed.

Recently, a spray of oil-based formulation of I. fumosorosea through an agriculture drone was carried out in coconut plantations of Tumkur District, Karnataka, India. Economic analysis of the impact of these advisories resulted in a Rs 9500/ha reduction in crop protection and a reduction of 900 ml of pesticides/ha. Besides the bio-suppression of invasive whiteflies, this also conserves the natural enemies in the coconut ecosystem and protects the environment.

Extensive extension efforts of the ICAR-NBAIR in motivating farmers and other stakeholders such as ICAR-KVKs, CIPMCs and line department officials on biological control of these invasive whiteflies resulted in the spread of technology among various stakeholders and adoption of biological control against whiteflies in coconut and oil palm gardens.

(Source: ICAR-National Bureau of Agricultural Insect Resources, Bengaluru)