Amidst coronavirus pandemic, whitefly infestation may cause havoc in coconut and horticulture crops in the state

Biswabrata Goswami

KRISHNAGAR, 15 APRIL: Amidst the coronavirus pandemic, whitefly infestation has started causing widespread damages to coconuts and horticulture crops across the state.

The scientists of Bidhan Chandra Krishi Viswavidyalaya (BCKV) have already sounded a warning bell on the increased bio-security risks arising from the uncontrolled exchange of plant materials.

Dr Dipak Kumar Ghosh, associate professor and officer-in-charge, ICAR AICRP on Palms, BCKV said, “The Rugose Spiralling whitefly (Aleurodicus rugioperculatus) is solely responsible for the widespread damages to coconuts and other horticulture crops. Initially, it was started in South India a few years back and now it has spread to other states including West Bengal”.

Dr Ghosh, who is conducting research along with Professor Partha Pratim Dhar, Entomologist of RRS, Sekhampur, said, “With the infestation of the flies, the upper most portion of the leaves turn blackish in colour due to fungal growth. The fungal growths then cover the greenish portion of the leaves thus reducing the photosynthesis. Gradually, the plant is weakened and finally it will die”.

“Last year, we had seen the infestation of the whitefly in the coconut trees, but this year, we are getting information from different parts of the state including Nadia that other horticulture crops have already been affected. As the chemical pesticides are not effective to kill the flies, we are conducting research on the usage of organic pesticides like neem oil, plant extracts etc. Though, usage of neem oil has little effect but plant extracts have knock-down effect”, said Dr Ghosh.

According to the scientists, whitefly is a polyphagous pest, which means it can consume various kinds of food. It feeds on more than 200 host plants, including coconut, areca nut, banana, guava, mango, colocasia, jackfruit and other ornamental plants that have a market value. Excessive feeding leads to excretion of honeydew which is deposited on the upper surface of the leaflets, resulting in the growth of sooty mould. This, in turn, causes disfigurement of the host, affecting photosynthetic efficiency of the plants.

When asked, Prof Dhar said, “RSW is an invasive insect infesting new area due to absence of its predator and parasitoids. For management of such invasive pests eco-friendly management strategies need to follow. First, quick suppression of this insect by using non-chemical methods. Secondly, to stop the spreading of the insect attacks following collective measures. Thirdly, the awareness of this insect attack among farmers. We have identified an organic that is plant extract ( Solanum Xanthocarpun and Plubago indicum)  is used in tea plantations against sucking insects.

Based on the above three principles farmers should immediately take measures collectively for quick suppression and spreading of this insect.”

“Hotter temperatures favour the growth of sucking insects such as whiteflies. The prolonged dry spell during June to September coupled with decreased relative humidity may appear to favour the spread of the pest in coconut plantations,” a BCKV researcher said.