Physiological plant disorder diseases. Improving drainage will help to alleviate this problem. Hail can cause damage to soft skinned fruits, and may also allow brown rot or other fungi to penetrate the plant. Brown spot markings or lines on one side of a mature apple are indicative of a spring hailstorm. Plants affected by salt stress are able to take water from soil, due to an osmotic imbalance between soil and plant. Poor growth and a variety of disorders such as leaf discolouration (chlorosis) can be caused by a shortage of one or more plant nutrients. Poor plant uptake of a nutrient from
The Limits to Growth continue indefinitely, but that a natural end to growth was preferable to intervention. Wallich stated that technology could solve all the problems the report was concerned about, but only if growth continued apace. By stopping growth too soon, Wallich warned, the world would be "consigning billions to permanent poverty". Julian Simon, a professor at the Universities of Illinois and, later, Maryland, argued that the fundamental underlying concepts of the "LTG" scenarios were faulty, because the very idea of what constitutes a "resource" varies over time. For instance, wood was the primary shipbuilding resource until the 1800s, and there were concerns