Diagnostic Analysis and Comparative Discussion of Stem Rot and Soft Rot

A few days ago I happened to publish an article titled "Also Talking AboutSoft Rot, Stem Rot and Some Small Prevention Tips"; an orchid enthusiast named "Hen" raised an objection to my view that the two diseases belong to the same category! Over the past few days, I have consulted a large amount of relevant material both online and offline, which proves that my view was wrong; I hereby express my deep gratitude to fellow orchid enthusiast "Hen"! And I make the correction: 'Soft Rot' is a bacterial disease; 'Stem Rot' is a fungal disease! Now I have gathered together the pictures obtained online, to discuss, compare, analyze and diagnose together with all fellow orchid enthusiasts, in order to learn from each other and improve together. (The pictures requested come respectively from: Suxin Caotang, Xixi and another orchid enthusiast's pictures.) It can be said that 99% of orchid enthusiasts today do not have advanced instruments; but we can identify and diagnose based on the appearance of the diseased plant, in order to take decisive action early. From the comparison of the following 3 groups of pictures: "Xixi's" group of pictures and "Suxin Caotang's" and the "third group of pictures" are clearly different; 1. Different manifestations of leaf shrinkage in diseased plants: 1. From Xixi's middle picture, when dehydration is so obvious, the leaves have not turned yellow; while "Suxin Caotang's" "Songmei" and the "third group of pictures" show slight leaf shrinkage, yet the leaf color appears dull yellow; the earliest sign is that the base of the heart leaf's foot turns yellow first, then develops into the whole plant withering and yellowing! 2. Xixi's middle picture shows the typical symptoms caused bySoft Rot! First, the heart leaf of the infected plant can be pulled up with a gentle tug, and the base shows black rot and decay; whereas those shown in "Songmei" and the "third group of pictures" cannot have their heart leaves pulled out; "Songmei" and the "third group of pictures" show typical symptoms of Stem Rot! 2. Different colors of the pseudobulb of diseased plants The pseudobulb of "Soft Rot" is dark-colored and corroded; the pseudobulb of "Stem Rot" is light brown in the early stage, and shriveled. It then develops into dark brown and shiny, with even more obvious shriveling! 3. Development of the diseased plant "Soft Rot" spreads to nearby plants through adjacent parts, and if discovered early, uninfected orchid plants can mostly be saved; whereas "Stem Rot" spreads through body fluids, and even if discovered early, the survival rate of adjacent orchid plants is extremely low. (This view is collected theory.) 4. Treatment What needs to be pointed out is that when you find during the plum rain season and the scorching summer days that an orchid plant suddenly has leaf shrinkage, or the base of the heart leaf's foot turns yellow, remove some of the surface potting medium and check carefully; once symptoms are found, operate immediately (please use a sharp knife, not scissors; the reason is simple, cutting with scissors squeezes the tissue); do not delay; once tissue necroses, it cannot regenerate or repair. 5. Points to note when introducing new plants Please look at the root and pseudobulb picture of Longzi; the base of the seedling facing directly has a black ring, and the roots are not good; when you encounter such a seedling, do not be tempted by a cheap price. 6. Prevention The two diseases are preventable but difficult to cure, so prevention should be the priority! To prevent "Soft Rot", "chloramphenicol" and "streptomycin" can be used; both are broad-spectrum antibacterial agents. "Chloramphenicol" has a broader antibacterial spectrum and stronger antibacterial power. To prevent "Stem Rot", "metalaxyl" can be used To kill both bacteria and fungi, "Keshade" and others can be used Author: Jin Xin