are these good or bad pest on my outside plants spider and some bug

[ComfortablyNumb]

Milk residue??

 

[biggerbud420]

Milk residue??

Using Milk to Prevent Powdery Mildew

You don't have to garden long to become acquainted with the disease called powdery mildew, which creates whitish patches on the leaves of many plants. I have found that it can be controlled with regular sprays of milk and water...

www.growveg.com