Photo period cannabis problem in flower

[mh4l]

Pics are from today.

The white powder is for bugs.

Why is the viens on my leafs turing yellow.


I have had temps above 100 for last week every day and night temps of 80-90!

 

[GoAuto6]

How old is this plant? Are they mostly the older leaves? She dose look hungry but it could be heat stress, they start to use up older foliage first as they start to finish.

 

[Waira]

.... the yellow veins, greener interveinal space pattern, I've seen before but never found a definite answer,.. only thing close is a rarer Fe defc. symptom manifestation,... likely linked to the heat,..
... what specifically is that white residue? getting anything like that on the buds is unwise, even if it's DE,...