ethylene phytotoxicity of tomato

Ethylene phytotoxicity-This is not an infectious disease. May occur in greenhouses when there is inadequate exhaust or faulty heaters. Note epinasty. 

Ethylene damage on tomato seedlings Figure 1. Ethylene damage on tomato seedlings. Ethylene has caused the branches to turn down (epinasty). Note that younger leaves are not pointed down since heaters were fixed so that ethylene was not longer a by-product.
Close-up of branches with epinasty due to ethylene. Figure 2. Close-up of branches with epinasty due to ethylene.