The absorbed energy is converted to heat energy. The scenario you mention with the LED is very close to the blackbody problem known as the ultraviolet catastrophe.. There is a Wikipedia article about it here. What happens in the situation you described is that the light proof box gets hotter.
Diagnosing rust on geraniums can be a challenge for growers. Rust begins with yellow spots on the underside of the leaves and can rapidly progress with brown fungal spores called pustules in the center of each spot. The pustules are raised up off the leaf surface and feel rough to the touch.
Butterfly Bush Has Brown Leaf Spots. Growers are often alarmed when leaf spots appear suddenly and spread across leaf surfaces. Buddleia leaves with spots can be caused by a few different problems, including fungal disease and sap-sucking pests. butterfly bush with spotted leaves should be checked carefully from top to bottom before treatment, just to be sure youâve fingered the right culprit. Advertisement. Fungal leaf spots and downy mildew cause many widespread spots, ranging in color from yellow to tan and even black or brown.