To op. Just got word from Matthew Gates, zynthenol on yt, synchagel on Ig. Confirmed witches broom.
Thing is, Ive Never seen a photo, from an expert source, that showed the Viroid/Phytoplasma ect- that is purple black. Ive seen extremely twisted leaves, and other things, but Ive never seen a photo, taken by someone knowledgeable, that shows the disease, as Black/Purple.
Also, not saying it isnt Witches Broom, as it very well may be. But, Ive never seen someone with expert knowledge, and photos, showing the disease, as Black/Purple. Nor have I read descriptions of it being Purple/Black.
Also, of course Ive not seen nearly every photo, on the internet-forums ect, so, I could be missing something. I will always have an open mind. Dont have an open mind, at ones own peril.
And, if it is Witches Broom, these no cure. Only prevention.
Also the clustering of leaves, branches ect, that are mentioned by this scientist, is not typical of the disease Ive seen. It usually turns purple, black, and dies. Though, some do grow out of it But it doesnt cause the type of growth explained in this article.
Also, Witches Broom,, and Whatever the Purple/Black stuff is, are both transmitted by Leafhoppers, and other chewing/sucking type insects.
The only way to eliminate it, is to keep leafhoppers ect, off of the plants, which may in many cases, be impossible to do.
Phytoplasmas are bacteria that live in insects and plant phloem, or the living tissue that transports important resources like sugar. Unlike non-fastidious bacteria, which are culturable on growth media and generally cause plant tissue decay, phytoplasmas are phloem-limited parasites and mainly cause significant alteration of plant growth and development. Typical symptoms include clustering of little branches (witches’ broom), phyllody (developing floral organs on leafy structures), greenish pigmenting in non-green flowers or shoots (virescence), and yellowing and stunted plants. In certain varieties of hemp, phytoplasma-infected plants develop clusters of highly proliferating branches with significantly shortened internodes (Fig. 2, above). Leaves in a cluster are tiny, crowded, sometimes yellowish. Leaves outside the cluster turn yellow and sometimes are deformed. Early infected plants may be severely stunted when compared to a normal plant. Young plants may die off during the early season. A May 2019 disease note published in
Plant Disease confirmed the presence of ‘Candidatus Phytoplasma trifolii’ in U.S. hemp crops.
THAT DESCRIPTION IS NOTHING LIKE I HAVE SEEN. AND STILL NO MENTION OF PURPLE/BLACK.
Phytoplasmas generally are transmitted by phloem-feeder insects in the order Hemiptera, particularly leafhoppers, planthoppers, and psyllids. Inside the insect vector, phytoplasmas can survive and are stored in the guts and salivary glands, with the ability to move to the saliva. When a phytoplasma-carrying vector feeds on a plant, it delivers phytoplasmas into the phloem via saliva. Therefore, the host range of a phytoplasma largely depends on the plant feeding range of its vector, which is generally broad.
One of the most effective practices to manage phytoplasma diseases is to periodically monitor and control insect vectors, especially leafhoppers, which can also help mitigate hemp leaf curl caused by Beet curly top virus. Although phytoplasmas are mainly transmitted through leafhoppers, they can also be spread via propagation materials such as cuttings and seeds. Therefore, mother plants should be periodically tested for the phytoplasma to prevent the dissemination of the disease to progeny plants. Seeds should be tested and verified to be free from phytoplasma infection.
Correct Diagnosis
The virus, viroid, and phytoplasma all infect cannabis plants systemically and induce abnormal growth. Although symptoms caused by each organism are distinct to some extent (for example, witches’ broom is more likely to be caused by a phytoplasma infection, leaf curl by Beet curly top virus, foliar chlorosis by Lettuce chlorosis virus, and stunting by Hop latent viroid), there are significant overlaps in symptom development among these diseases. One pathogen can cause multiple symptoms that may resemble other diseases and, in some cases, a crop can be infected by multiple pathogens.
To correctly diagnose complicated and overlapping abnormal-growth diseases, one can perform a symptom polling in the field to determine the prevalence of each symptom type by referencing what the polltaker sees to each typical symptom caused by phytoplasma, virus, or viroid. As described in detail in my book
“Diagnosing Hemp and Cannabis Crop Diseases” this strategy helps to correctly classify each symptom observed and calculate the percentage of plants exhibiting witches’ broom, leaf curl, mosaic, chlorosis, yellowing, or twisting. This process greatly helps determine if a phytoplasma, a virus, a viroid, or a combination of them are contributing to the disease, which will guide subsequent sampling processes for targeted testing.
Shouhua Wang, Ph.D. is a plant pathologist with the Nevada Department of Agriculture.