Climate change, soil deterioration, unhealthy trees and excessive use of pesticides have been found to be key factors contributing to the devastating thrips attack that has threatened to decimate the season’s yield from the mango orchards of Muthalamada in Palakkad district.
Entomological studies conducted by the scientists of the Kerala Agricultural University (KAU) have revealed that Muthalamada, the mango city of Kerala, can be salvaged only through a comprehensive approach by addressing all those issues.
“Addressing thrips menace by applying some pesticides alone will not solve the issue,” said Berin Pathrose, assistant professor of entomology at the College of Agriculture, Vellanikkara. “We must take a holistic approach to address the issue,” Dr. Pathrose told The Hindu.
Abnormal flowering of mango trees in the last five years has been found to be the main reason for the increasing presence of thrips. According to Dr. Pathrose, sharp fall in the low temperature can be beneficial to thrips.
The orchards of Muthalamada used to flower in September-October period and start giving yield by January. However, untimely rains in October-November delayed the flowering until January. Muthalamada had witnessed its lowest temperature in the third week of January at a time when the orchards flowered again. “This abnormal timing has helped thrips considerably,” said Dr. Pathros.
Facing thrips attacks or not, the trees flowering in January will give their yield by March-April. For Muthalamada, any yield in March-April will be a loss as it is the mango season all over the country. The advantage of Muthalamada used to be its January-February yield. “But we have lost that advantage because of climate change,” said M. Sachindran, a leading farmer.
Traders who take the orchards on yearly lease are found to be excessively applying pesticides. There have been cases when some applied even eight rounds of pesticides. “Excessive application of pesticides can kill the natural enemy population of pests. Integrated pest management (IPM) is needed here,” said Dr. Pathrose.
His studies found that the soil in Muthalamada had deteriorated vastly, with the boron micronutrient falling to zero level. With the soil losing its health, trees also become unhealthy. “Most trees in Muthalamada orchards are unhealthy. So it becomes easy for thrips to infest,” he said.
The farmers and traders of Muthalamada are widely using Cultar (which contains paclobutrazol), a flowering hormone, for induced flowering by retarding the growth of the tree. “Application of Cultar on unhealthy trees can have negative effects,” said Dr. Pathrose.
Scientists say pesticides are available against thrips. But their high cost will forbid the traders from using them, especially with the prospect of a delayed yield.
“The farmers have to correct the basics by improving the health of the soil and tree. They should address the issue fundamentally,” said Dr. Pathrose.
