Many plant problems and deaths are the result of environmental conditions rather than insects or disease. This includes but is not limited to overwatering, underwatering, air pollution, herbicides, pollination problems, nutrient deficiencies, salt injury, scorch, lightning damage, and mechanical damage. In some cases these causes may be quite evident but in other cases the real cause may be hard to identify. In many cases the primary cause of plant decline may be an environmental condition and only after the plant became stressed and weakened did it become attacked by insects or disease. In these cases if the environmental problem had been addressed early, insects or disease would not have been a problem.