Whitefly inflicts damage on cotton

Ludhiana, Aug 18 (UNI) On account of the prevailing dry spell and serious damage by cotton whitefly in isolated fields, the crops have been badly affected, said Dr N S Butter, Professor and Head, Department of Entomology, Punjab Agricultural University (PAU).

Pest damages the crop by sucking the sap from the leaves as a result of which the shedding of leaves takes place. While sucking the sap, the whitefly excretes honeydew on which black sooty mould develops which interferes in the photosynthesis activity of plants.

Prior to the development of sooty mould, the leaves become sticky to touch. Besides, these insects are responsible for the spread of cotton leaf curl virus (CLcV), Dr Butter said.

''First of all, the farmers are required to examine their cotton fields for the presence of whitefly. The presence can be ascertained by shaking the plant due to which the adult whitefly fly like smoke and soon settle down on the same plant on the underside of the leaves,'' he said.

Dr Butter suggested that at this stage, cotton crop is in fruiting stage, therefore, attack of both whitefly and bollworms can occur. It is, therefore, advisable to use those insecticide which can take care of both bollworms and whitefly such as triazophos 40 EC (Hostathion) at 600 ml/acre or ethion 50 ED (Fosmite/Emite/Volthion) at 800 ml/acre.

Any one of these insecticides can be sprayed using 125-150 litres of water/acre with knapsack sprayer.

The pesticides can only be used as soon as the population of adult whitefly reaches six adults/leaf before 1000 hrs or development of honeydew on 50 per cent of the plants, Mr Butter said.

UNI