COIMBATORE:
Scientists in
TNAU have asked maize farmers to beware of a new invasive
pest that is seen in maize plantations in
Tamil Nadu, Karnataka and Andhra Pradesh in July.
The invasive pest called
fall armyworm (FAW), Spodoptera frugiperda, native of North and South America, attacked a small portion of maize plantations on Tamil Nadu Agricultural University’s campus farmlands. Scientists request farmers to be alert for its symptoms. They say it is a pest that can be managed with the right guidance.
On Tuesday, scientists from the maize department and entomology department of TNAU showed samples of a few maize plantations where the fall army worm was noticed and slides in which the worm had been collected for specimen studies.
“The fall army worm was observed in the maize growing districts like Coimbatore, Erode, Tirupur, Dindigul, Karur, Villupuram and others in July,” said N Muthukrishnan, department of agricultural entomology.
Maize is cultivated in more than 20,000 hectares in Coimbatore district.
Scrapping of leaves, pin holes on leaves, irregular shaped holes on leaves, loss of top portion of the leaves, presence of chewed up frass material among others are the symptoms farmers should be on the lookout for to detect the pest.
“The worm’s larvae start causing damage from 15 days after sowing and continue their ravage on tassels and cobs,” said Muthukrishnan.
Thorough ploughing is a control measure advised if the pest is noticed. It is to ensure that the pupae hiding under the ground is exposed to birds and natural predators.
“Applying 250kg of neem cake per hectare to reduce adult emergence from pupae, using light trap to monitor adult activity in the evening, avoiding growing maize crop after crop, collection and destruction of egg masses and different stage of larvae and using synthetic insecticides like Azadirachtin, Thiodicarb can be used in the right quantity,” said Muthukrishnan.
While adult moths are covered with greyish white hairs on the upper surface of leaves, larva has an inverted Y mark on the head and cluster of four dots in the abdomen region and can be seen on leaves.
Possible reasons for the outbreak is touted to be continuous availability of vegetative, tassel and cob stages of maize, cool weather along with intermittent rainfall and absence of suitable predators due to excessive use of insecticides by farmers.
