Leaf galls on Alstonia tree under a foldscope

Chandigarh is a well-planned city and known for its green landscaping. Several avenue trees can be seen along the roadsides, nature parks and green belts. Alstonia scholaris, commonly known as blackboard tree of the family Apocyanaceae is one of the trees lining the city roads. Since last few years, these trees have lost their beauty due to gall formation.

One such tree was spotted near the college campus that had galls on the leaves. I collected its deformed leaves to study the Alstonia leaf galls. The symptoms observed were:

  • Formation of galls/warts on leaves
  • Distinctive deformation of leaves due to these galls
  • Yellow and greenish hypertrophied areas on leaves
  • Leaf curling
  • Yellowing of leaves
  • Chlorotic and necrotics patches on abaxial side of leaves

A sample from the gall viewed under the foldscope revealed distinct vein clearing, chlorosis (leaf yellowing in patches and infected patches. To my astonishment, I could see leaf aphids mimicking yellowed leaves  and probably the main cause of gall formation on Alstonia leaves. Reviewing the literature, I came across an interesting article ‘ Galls on Alstonia scholaris leaves as air pollution indicator’ according to which the leaf galls of A. scholaris were induced by a bug, Pauropsylla tuberculata crawf., which is an homopteran insect. Also the article highlighted the formation of galls due to increased levels of pollutants in air.(https://www.researchgate.net/publication/305618250_Galls_on_Alstonia_scholaris_leaves_ as_air_pollution_indicator)


Galls and hypertrophied deformation on leaves


Histopathological symptoms seen on leaves of Alstonia

Aphid observed under foldscope 


2 Comments Add yours

  1. Manu Prakash says:

    That’s a wonderful and detailed post @Rahul. Delighted to see this..

    I am also listing a few ther gall sightings under a foldscope:


    Keep Exploring.

    1. Rahul_SD13 says:

      Thanks sir for your motivation.


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