🦠 Why Is My Plant Sick/Dead?
One of my bonsai-anxieties is a sudden illness or sudden dead. I must record and diagnose the cause and seek a remedy for future reference:
?
Korean Hornbeam Discolored Leaves
Brown/Browning leaves on K. hornbeam (Jul)
August—light brown, thought it was not getting enough light so put it on a sunnier table. More turned brown.
Will not overwater, but move to a shadier spot
Koto Hime Maple (Aug)
Trident or Maple (Aug)
Coast Redwood (sick foliage)
Lodgepole Pine
What It Likely Is
Mealybugs or Scale Insects: These sap-sucking pests secrete a waxy, cottony, or fuzzy white protective covering. Left unchecked, they drain vital nutrients, weaken the tree, cause needle yellowing, and can eventually kill a bonsai.
Pine Bark Adelgids: Similar white woolly masses can appear on pine bark and needle clusters, feeding on plant juices.
Common Treatment Options
Isopropyl Alcohol & Q-Tip: Dip a cotton swab in rubbing alcohol (isopropanol) and dab it directly onto the white fuzzy clusters to dissolve their waxy coating and kill the bugs on contact.
Insecticidal Soap or Diluted Dish Soap: Spray the tree thoroughly with a gentle insecticidal soap or a mild, diluted dish soap solution to target crawling nymphs and remaining insects.
Neem Oil or Systemic/Horticultural Oils: Apply neem oil or a horticultural oil spray, making sure to follow product instructions for conifers, as sensitive bonsai foliage can react poorly to heavy oils in direct hot sun.
Keep a close eye on the tree and repeat treatments every few days to a couple of weeks, as hidden eggs or newly hatched crawlers may emerge.
