In nature. The plant or plants as a disease. 3 key factors arising from the properties together is the cause of the disease. Weak plants and environments which facilitate the disease when these factors are all reasons to plant 3 is a disease.
The nature of the plant or tree disease. 3 main factors, together, are the causes of weak plants and the environment which is conducive to disease. Once you have completed the 3 main factors such plants would be unhealthy.
In nature, the plants or trees are caused by the factors of three assemble together is the cause of the disease, plant weak environment and contributing to the disease. Whenever such factors of the three