Citrus susceptible to citrus greening disease infection by psyllid during flush

[Vlad]

So pesticides would be more effective during flush.
Here is the article: http://www.eurekalert.org/pub_releases/2016-02/esoa-pbg021216.php

[fyliu]

That's a pretty big difference. Pesticides during the entire flush, especially when the new leaves are larger but not hardened yet.