A recent study has highlighted an escalating issue within India’s agricultural sector – invasive whiteflies. These minuscule, sap-sucking insects are thriving in the country’s vegetable and ornamental plantings, particularly during warm weather. Their presence results in direct and indirect yield losses, affecting a spectrum of crops across agriculture, horticulture, and forestry sectors.
The Spread of Whiteflies Across India
Whiteflies were first reported in India with the appearance of the invasive spiralling whitefly (Aleurodicus dispersus), which has now spread throughout India, excluding Jammu & Kashmir. Another species, the rugose spiralling whitefly (Aleurodicus rugioperculatus), was first found in Pollachi, Tamil Nadu in 2016, but is now common throughout the country, including Andaman Nicobar and Lakshadweep islands. These two species have respectively affected over 320 and 40 different plant species. It’s noteworthy that most of these whitefly species originate from the Caribbean Islands or Central America.
Reasons for the Whitefly Proliferation
The underlying reasons for the exponential spread of these invasive whiteflies include their polyphagous nature, which allows them to feed on various kinds of food, and their prolific breeding capacities. Furthermore, increasing globalization, human movement, and importation of plants have facilitated the dissemination of different varieties of whiteflies, resulting in their growth into invasive species.
Concerns Caused by Whiteflies
The whiteflies pose a significant threat to crop production due to their detrimental effects on yields and the direct damage they cause. Approximately 1.35 lakh hectares of coconut and oil palm plantations in India are currently affected by the rugose spiralling whitefly. Moreover, different types of invasive whiteflies were also found to increase their host range on valuable plant species, including coconut, banana, mango, sapota, guava, cashew, and oil palm. They also target ornamental plants and important medicinal plants.
Challenges in Controlling Whiteflies
The current synthetic insecticides have proven to be inefficient in controlling the whitefly population. Alternatively, biological control methods are being employed to manage the situation. These include naturally occurring insect predators, parasitoids, and entomopathogenic fungi that specifically target whiteflies. These methods are not only beneficial for the environment but also economically feasible.
Other Pests Affecting Indian Crops
In addition to whiteflies, crops in India also face threats from several other pests such as the Fall Armyworm (FAW), locusts, and the Pink bollworm (PBW). The FAW is known for its rapid spreading nature and has been reported to launch attacks on crops in northeastern Assam. To combat the armyworm menace, the Food and Agriculture Organisation has initiated a Global Action for FAW Control.
Locusts, often referred to as ‘tiddi’, are migratory insects known for their powerful flight capabilities and their ability to form devastating swarms. They pose a significant threat to crops and food security by consuming large amounts of fresh vegetation.
The pink bollworm, while native to Asia, has emerged as a troublesome pest in the global cotton farming sector.
Implementing Measures for the Future
To mitigate the damages caused by these pests, continuous monitoring of the occurrence and spread of invasive species, their host plants, and geographical expansion is vital. Furthermore, if necessary, the import of potential natural enemies for bio-control programs can be pursued. Through collective and timely efforts, it will be possible to combat these invasive species and safeguard the future of Indian agriculture.
