MULTAN - Director Central Cotton Research Institute (CCRI) Multan Dr Zahid Mahmood on Monday advised farmers to delay first spray on cotton crop for as long as they could, adding that spray should be applied only when pest incidence crossed economic threshold level (ETL). In a statement issued here, CCRI Multan chief said that April sown crop, if facing incidence of Thrips and Aphid beyond ETL, should be sprayed after consultations with the agriculture officials. Dr Zahid said that farmers should install 6-8 pheromone traps per acre to counter pink bollworm when the crop is passing through flower stage.