The last two years saw turmeric prices increasing in area under cultivation in Tamil Nadu. It has replaced many cash crops and has been grown even as a rainfed crop. As it replaces primary crops the incidence of pest and disease also increases.
In Dharmapuri district, white grubs which are infesting sugarcane are found to be feeding on the rhizomes of the turmeric.
The initial symptoms are yellowing of leaves and wilting. The infected plants can be removed from soil easily. Under the infected plants are fleshy “C” shaped creamy white grubs with swollen dark abdominal segment.
They feed on the newly formed rhizomes which lead to the wilting of plants. Mostly the whitegrub infestations are noticed in fields where the sugarcane was the previous crop or cultivated in the adjacent field. The adult whitegrubs become active with the onset of summer showers (May – June). They come out of the soil during the dusk, feed on leaves of neem, Acacia, Ailanthus etc and mate. The female lays the eggs in the moist soil.
After emergence the grubs start feeding on the soil organic matter and rootlets. The grub completes three instars and the damage is noticeable during July to September (i.e. third instar larvae).
Provide adequate irrigation, since under inadequate soil moisture conditions the pest appears in the root zone.
Collect and destroy adult beetles when they are found feeding on the trees.
Install light traps to collect the adults (or) burn fire. Adopt crop rotation in the endemic areas
Apply Lindane 1.3D 125kg/ha or Carbofuran3G 10kg/ha near the root zone and give one more round 30 days later.
Krishi Vigyan KendraTamil Nadu Agricultural University, PapparapattyDharmapuri