White grubs are severe during the Kharif season (south-west monsoon, June to October). The female adults enter into the soil to lay eggs. The grubs after hatching start feeding on roots. Severely infested fields have large patches of dead plants; the surviving plants are often stunted and show signs of wilt. Such plants can be easily pulled out.
In the younger sprout infection starts at the collar region of the pseudostem and progresses upwards and downwards with the characteristic foul smell. Yellowing of leaves spreads to all leaves of the plant from the lower region upwards followed by drooping, withering and drying of pseudostems
It is also a soil born disease. First symptoms of infection start with mild wilting / curling of lower leaves that progress upwards. As the disease progress, leaves droop down and plants exhibit severe yellowing and wilting, topples down producing petrifying smell.
Occasionally infected plants show stunted growth, chlorosis with necrosis and burning/drying at the leaf tips. Infested seed rhizomes look shrivelled with sunken or swollen patches on the outer surface. Root galls and lesions are seen on the roots.
Validated Integrated Pest Management Interventions for Ginger Crop
- Use well-decomposed FYM impregnated with Trichoderma harzianum at 250 g / q FYM.
- Soil solarization of the fields with transparent 0.45 mm thick polythene sheet for 15-20 days may be done before sowing.
- Seed rhizomes can also be solarized by keeping inside the polythene for two hours.
- Treat the seed rhizome with fungicides like carbendazim 50 WP @ 100 g + mancozeb 75 WP (250g) dissolved in water or with Trichoderma harzianum at 6-8 g / litre of water for 30 minutes
- Control white grub adults by spraying their feeding trees like apple etc. with carbaryl 50 WP @ 2 g per litre of water. This spraying may be repeated from 3 to 4 times until mid-July, ideally using community approach.
- Give hot water treatment to seed rhizomes at 51oC for 10 minutes before planting.
- In standing crop, drench the fields with carbendazim 50 WP @ 0.2% or mancozeb 64 % + metalaxyl 8 % @ 0.25% along the roots of one month old crop or at the onset of monsoon.
- Treat the rhizomes meant for seed (75-80 kg) purpose with carbendazim 50 WP (100 g) + mancozeb 75 WP (250 g) + chlorpyriphos 20 EC (250 ml) mixed in 100 litres of water for one hour and shade dry before storage. Empty space may be filled with dry grass. The pit is covered with a wooden piece and cemented with cow dung.
- National Research Centre for Integrated Pest Management