Prevention is better than cure! Keeping your grow room in good clean order will be the best preventative measure you can take. Keep the floor clean and keep the equipment clean. Growers tools often carry microscopic pests, fungi and disease that can destroy your crops. Regular cleaning of these must be taken, esp when taking clones. Mulch can cause problems too as the insects and fungi love to hide under this. Don't leave any decomposing matter in your grow room as this causes depletion of oxygen. Your plant roots need the oxygen as lack of it causes root death! It is best to give your grow room and all equipment a complete wash down between crops. Keep your grow room clean, neat and tidy during your cycle. Its a good idea to hang a sticky fly trap up too as this gives you an idea of what has been visiting. That way you can identify and treat at an early stage. Most growers prefer organic based insecticides as your'll be consuming your crops sooner or later.