The infestation of Fall Armyworm (Spodoptera frigeperda), an invasive agricultural pest that was first noticed in Shivamogga district in May this year, is spreading at an alarming pace in Karnataka.
Entomologists C.M. Kalleshwara Swamy and Sharanabasappa found that the maize crop, cultivated on the demonstration plots on the campus of the University of Agricultural and Horticultural Sciences (UAHS), Shivamogga, in May was devoured by a new variety of pest. The scientific examination revealed that the pest was Fall Armyworm that had wreaked havoc on maize crops in Africa in 2016. The DNA barcoding of the moth, collected from the fields, done at Indian Institute of Horticulture Research, Hessarghatta, in July, confirmed that it was Fall Armyworm. The spotting of the worm in Shivamogga plot was considered as the first incidence of Fall Armyworm infestation in Asia.
Following this, cases of maize crop infected by the Fall Armyworm have been reported from Davangere, Chitradurga, and Haveri districts in the second week of July, and from Belagavi, Ballari, Chickballapur and Kolar in the last week of July. In August, the infestation was reported in maize plots in Bhadravati, Sorab, and Shikaripur taluks in Shivamogga district and in Hassan and Mysuru districts. Barring the coastal zone, its presence has been reported in nine other agro-climatic zones in Karnataka.
Mr. Sharanasabappa told The Hindu that the lifespan of the pest is 30 to 60 days and each generation can migrate to a distance of more than 400 km. The fecundity of this pest is also high. Owing to these factors, the infestation is spreading at a rapid pace. Srinivas B.Y., Director of the Department of Agriculture, said there is no clarity on the total acreage of land in Karnataka that has been infested with the Fall Armyworm pest, though a survey has commenced, he said.
The area of cultivation of maize that was on 6.6 lakh hectares in the State in 2001 has enhanced to around 14 lakh hectare today. Many paddy growers in Malnad region have also switched over to maize as the latter is considered less-labour and less-water intensive. In many parts, mono-cropping of maize is practised.
Mr. Sharanabasappa said that mono-cropping brings damage to the soil ecology. The diversity of nutrients in soil will be depleted with mono-cropping, making crops vulnerable to pest infestation. As soon as the infestation is noticed, farmers have been directed to undertake Lambda Cyhalothrin or Carbofuran pesticide spraying to control the menace. After pest control measures, the plants have been known to recover and their growth is normal. The formation of cob in the maize plants sown for kharif season has just commenced. The actual yield loss from the infestation can be quantified after the harvesting, he said.
Mr. Sharanabasappa said that though Fall Armyworm can feed on more than 100 varieties of crops, as of now, its infestation has remained confined to maize and sorghum in Karnataka.
Meanwhile, Tirupati and a village in Chandragiri Mandal of Chittoor district of Andhra Pradesh too have reported incidences of Fall Armyworm infestation.