Is it wrong livelihood to pick up cherries? I currently am taking care of an organic garden and minimizing any harm that could befall on any living beings by sustainable techniques, and on the side am helping to pick cherries and yet I have discovered that they use a product (insecticide) to treat the cherries.
Am I somehow earning a wrong livelihood by picking them up ?

Considering the five different types of wrong livelihood 
AN 5.177


  Monks, a lay follower should not engage in five types of business.
  Which five? Business in weapons, business in human beings, business in
  meat, business in intoxicants, and business in poison.
  
  "These are the five types of business that a lay follower should not
  engage in.


May you be blessed.
Picking cherries is not a wrong livelihood as long as you are not the one spraying the pesticides.

Spraying pesticides is a wrong livelihood as it harms others (by doing activities which do not fall under right action to earn a living). Generally, distancing yourself from this activity would be fine as long as you can say free from remorse. If you are not involved in any way and this is out of your control there is nothing to be remorseful about it. If you still feel remorseful maybe it might be wise to find another side job.

Maintaining the organic garden within the law and ethical norms are definitely right livelihood.

The main objective in morality is Buddhism is to develop all other elements in the Noble Eightfold Path. Morality (3. Right speech 4. Right action 5. Right livelihood) helps develop mastery over the mind (6. Right effort 7. Right mindfulness 8. Right concentration) which intern helps wisdom (1. Right view 2. Right resolve). Right livelihood should be practised as a connected whole with other parts of the path so that one is free from remorse which helps develop meditation. If one is not free from remorse one cannot develop mentation and intern insight which is the pinnacle of the path.


  (5) Bhikshus, for one with right livelihood, there is the withering away of wrong livelihood; and also
  the withering away of the many evil unwholesome states that arise with wrong view as condition,and the many wholesome states that arise with right livelihood as condition are fulfilled through cultivation.


Maha Cattarīsaka Sutta