The earliest symptoms on 2-3 months old button is pale yellow triangular patches seen below the perianth. Later, these patches become brown.
Severely affected buttons may fall.
As the buttons grow, brown patches lead to black necrotic lesions with longitudinal fissures on the husk.
Uneven growth results in distortion and stunting of nuts leading to reduction in copra yield.
In severe cases, the losses are compounded because the quality of fibre is reduced and distorted nuts increase the labour requirements for dehusking.
Management
Collect and destroy all the fallen buttons of the affected palm.
Apply 2 per cent neem oil + garlic emulsion or commercial neem formulation azadirachtin 0.004 per cent (Neemazal T/S 1 per cent @ 4 ml per litre of water) or micronized wettable sulphur 0.4 per cent in the crown on young bunches.
