Show to control insect spread simple changes in routine farm op orations erat ions to deprive insects of food or shelter at critical periods in their life cycle affer a valuable control method according to united states en fists timely forecasts of the able performance of many insects based on the results of entomologic a studies now make it easy to out in inove ove these pests by advancing or del delaying abing aying seeding or harrowing by thoroughly clean ng up a threatened aea avea or by changing crop rotations |