Field tests for organic substitutes for endosulfan conducted at Kerala Agricultural University’s Cashew Research Station, Madakkathara, are yielding positive results.
“For long, the search for organic alternatives has been on. The health impact of the use of endosulfan in cashew plantations in north Kerala, especially of aerial spraying of the pesticide in Kasaragod, has been much discussed. The KAU’s research on organic cashew farming gained momentum after the State government had banned the use of endosulfan,” said P. Rajendran, KAU Vice Chancellor.
After field trials in KAU’s cashew plantations, scientists vouch for the efficacy of bio-agents such as entopathogenic nematodes, beauveria bassiana, metarhizium anisopliae, verticillium lecanii, hirsutella thompsonii, and pseudomonas fluorescens.
To control pests, scientists have also used pongamia oil, tapioca leaf extract, and azadirachtin concentration.
The major pests of cashew are tea mosquito bug and cashew-stem-and-root borer. Twenty pests have been identified by the Cashew Research Station. Two minor pests of cashew — spiralling whitefly and mango leaf webber — too have been spotted in KAU’s cashew plantations in Madakkathara.
“There are reports of endosulfan being smuggled into Kerala from Tamil Nadu. Farmers still use synthetic insecticides, though less toxic ones, in cashew plantations. For organic farming, bio-control measures should be regularly adopted and this would involve increased labour costs. Hence, farmers are reluctant to try them out. Organic cashew nuts fetch higher price that the chemically-grown ones,” said P.B. Pushpalatha, head of the Cashew Research Station and former KAU Registrar.
Gavas Raghesh, assistant professor (Agricultural Entomology), has been consistently carrying out experiments to find whether bio-control agents are effective.
“They indeed are. The plantations should be closely monitored and bio-control agents frequently applied,” he said.
Fall in crop productivity
According to Economic Review 2012, the area under cashew cultivation declined in Kerala from 1.25 lakh hectares (ha) in 1988-89 to 44,000 ha in 2010-11. In 2011-12, there was 23.3 per cent increase in the farming area.
Kerala’s share in cashew farming in the country came down from 23 per cent in 1987-88 to 5.4 per cent in 2011-12. The share of production declined from 31 per cent to 5.3 per cent in the same period. In contrast, farming area and production are increasing steadily in other cashew-producing States.
Cashew crop productivity in Kerala, which was around 900 kg a ha in the late 1980s, declined from 1995-96 onwards, touching 562 kg a ha in 1998-99 and thereafter hovering around 800 kg a ha. In 2011-12, it further declined by 14 per cent.
“Cashew farmers should discard conventional thinking and innovate. The KAU has found that inter-cropping (practice of growing two or more crops in proximity) may help cashew farmers. They may grow pepper, passion fruit, and pineapple in cashew fields. The research station has tried out all these crops and found it profitable. Some cashew farmers in Mananthavady in Wayanad district are already growing pepper in cashew fields,” said Ms. Puspalatha.
Cashew apple products
She said 60 to 75 per cent of cashew apple produced in Kerala was being wasted.
The research station has spent much energy in formulating cashew apple processing methods and developing products such as vinegar, jam, halwa, candy, pickles, cashew apple soda, and cashew apple chocolate. Two or three cashew apple processing units have been set up in the private sector under KAU’s guidance. The KAU has also provided 2.23 lakh cashew grafts to farmers since 2008.
