We Have A Huge Old Banana Shrub (magnolia) For Several Years It Has Had Scale Insects. I Treated The Scale Insects With OTC Produs

Question

ts which didn’t work. Last summer I used imidacloprid as per the recommendation of our agricultural extension agent. Starting this spring the shrub kept putting on new growth which promptly fell off. The leaves have a yellow green color. a sample of the leaves were sent to the state agricultural pathologist who did not have an answer other than the shrub was old and in decline. Can you help? This is a very large specimen.

Answer 1

Here are the proper care requirements which may give a clue to what ails the tree:

https://www.gardeningknowhow.com/ornamental/shrubs/banana-shrub/how-to-grow-banana-shrubs.htm

Also, they prefer acidic soil and perhaps the soil has been getting less acidic over the years. Another thought is that the scale has returned. Try horticultural oil.

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/raise-acid-level-soil.htm