Hello Jerry, 

Thanks for reaching out to the EMG helpline! Are you looking for a general insecticide or do you have a history of problems with the four trees? If you've had trouble with insects in previous years, can you share more information? This will help us to make the best recommendation.  

We have not had problems with insects in previous years. The four apple trees are three years old and I want to treat them to guard against insects but do not want to inhibit fruit growth in the process. Last year, I sprayed an oil based insecticide on the trees in late April and the blossoms on the trees died. This is why I seek your  advice.

Thank you.

Hello Jerry, 

Thank you for sharing that additional information. Last year's late and hard frost may have contributed to the problem you experienced with the flowers dying. 

Do you have a preference for conventional or organic treatments? I consulted with one of our internal experts about pesticide recommendations. She mentioned that most important sprays are for plum curculio at petal fall and 7-10 days later. Our neighbors at the Cornell University extension in New York have published an all around helpful guide for pest management in apple trees, which is found here: https://ulster.cce.cornell.edu/resources/apple-ipm-for-beginners. 

We hope this information helps and please feel free to reach out if you have any other questions.