Show dusting quite effective against certain insects that dusting can be used effective ly against certain insects has been known for 20 years but the u use so oi of contact insecticides such as nicotine compounds Is a more recent development while tile the actual cost of dust ing materials Is somewhat greater than that of spray materials the cost per acre Is usually less in addition the dusting dustin g process has the advantage of it a wider range of application inasmuch as moisture conditions do not affect the operation it seems to wo rk equally well whether the vines are wet or oi daiy dry diy wind seems to be the only limiting factor |