Can you please provide specific information regarding neem oil drench for white weeping birch trees? Oil to water ratio, quantity of solution to apply, when to apply to soil and any other relevant information. The trees are growing in coastal central California. Thank you!
Neem Oil Drench for White Birch Trees
Those look like harlequin ladybird larvae and they do not cause leaf damage. They are more likely there to eat some other pest that is present such as aphids. You need a positive ID on what is going on. Correct treatment depends on accurate diagnosis.