Thoughts and musings
Lewis | May 19, 2015 | 0 Comments
…is for (Aster) Yellows.
The end is near! This is the penultimate edition of our Garden Pests Series. I hope you enjoy it; it has been a very enjoyable for me to research, compile and write the whole Series. Be that as it may, let’s not say our goodbyes just yet! As it stands, you still have one more to enjoy after this one, which is going to focus on aster yellows, a chronic disease suffered by plants caused by phytoplasma, a bacterium-like organism. As such, the disease is commonly referred to aster yellows phytoplasma, or AYP. This particular garden pest may technically begin with the letter ‘A’, but I am using artistic licence once more!
As the name suggests, aster yellows is a disease that mainly affects herbaceous plants in the aster biological family – a flowering plant family, which includes sunflowers and daisies. In actual fact, AYP affect 300 species across over 20 biological families of plants. It is also very easily transmitted between plants; phytoplasma is a bacterium limited to travelling in the phloem structures of a plant’s vascular system and it transmitted by a vector, the aster leafhopper, an insect that feeds on a plant’s phloem. The importance of knowledge of AYP is vital, especially when you know how detrimental it can be…
Symptoms of a plant suffering from AYP include the development of a green pigment in areas that aren’t normally that colour, stunted growth and sterility. AYP also causes chlorosis, which means a plant’s ability to carry out photosynthesis, a vital process for plants to survive, is compromised or even not possible at all. So, considering this condition can potentially kill certain plants in your garden, we should all know about it! For such a small individual organism, phytoplasma certainly know how to make a gardner’s job difficult.
Sadly, there is no cure for AYP, which causes a huge headache for all of us, I’m sure! A few years ago my mother, who herself is a keen gardener, had a lovely bed of sunflowers in a border that sadly fell foul to the disease. All she could do, which I recommend you do if you find yourself in a similar situation, is to remove any plants that are affected, as this helps minimise spread. Also, there aren’t currently any chemical treatment methods that are effective, either, but some insecticides are effective at controlling the aster leafhopper. However, these are often broad-spectrum; be careful before you eradicate beneficial insects, too! My advice? Plant some flowers immune to the disease, such as geraniums. They look just as pretty and you won’t have to deal with AYP!
Photo credit: <a href=”https://www.flickr.com/photos/infomastern/14977268558/”>Infomastern</a> / <a href=”http://foter.com/”>Foter</a> / <a href=”http://creativecommons.org/licenses/by-sa/2.0/”>CC BY-SA</a>