Weather change has started affecting coconut palms. Scientists at the Central Plantation Crops Research Institute (CPCRI) have found a new species of white flies attacking coconut leaves. Lack of rain and low humidity are favourable conditions for the growth of the species, according to scientists.
Pest attack has been confirmed in Palakkad and Pollachi. Studies are being conducted in Kuttanad. No loss of yield has been reported, but photosynthetic efficacy could be partially affected.
“The pest is spreading, but in localised pockets. The identified white fly is a new species and more than 3,000 palms have already been affected,” one of the scientists associated with the study, who did not want to be identified, told The Hindu .
In Kerala, Tamil Nadu
The new species, named Aleurodicus , has emerged in certain pockets of Kerala and Tamil Nadu. Belonging to a sucking group of insects under bug category, it feeds from the under-surface of the coconut leaf in large numbers and the honeydew that they excrete attracts the black sooty mould fungus. Widespread appearance of black colour on the upper surface of coconut leaflets is the characteristic symptom that a farmer could notice initially, the scientist said.
Reported for the first time from Palakkad and Pollachi, the pest could spread to other coconut-growing tracts. Deficit monsoon and drop in relative humidity are the immediate reasons for the flare-up of the pest. Though reports are emerging from different coconut tracts in the country, there is no need for panic, according to CPCRI scientists.
Another species of whitefly, Aleurodicus dispersus , had been reported from Kerala in 1995 which infested more than 200 host plants then. Besides coconut palm, it was also found feeding on curry leaf, mango, banana, and other plants. But the newly identified species is specifically breeding on coconut palms.
Moth-like bug
The pest is a small moth like bug that lays eggs in a spiralling fashion in discontinuous circles. Females have dark blotches on wings and males have well-developed claspers on the abdomen. Apart from coconut palms, Aleurodicus dispersus was also found feeding on curry leaf, mango, banana and other plants.
Scientists said the pest attack could be curbed by encouraging the growth of parasitoids. During an observation of palms last month in Pathanamthitta district, it was found that about 60 per cent of pupae of Aleurodicus were found parasitised by Encarsia , another species.
Encarsia is a tiny parasitoid of size less than 1 mm, found effective in the bio-suppression of the whitefly under natural conditions. Research efforts for multiplication of the parasite identified by the scientists of the institute have been initiated by the ICAR-CPCRI.
Biocontrol strategies
Biocontrol strategies, including installation of yellow sticky trap on palm trunks and application of 1 per cent starch solution on leaves, have been advised to control the pest attack. No insecticide is recommended.
