Sorry but the first rule of pest control is to - first, ID the pest.

Not only are pest controls toxic, they are specific to the type of pest in many cases. Any sort of blanket pesticide, if one existed, is going to kill far more beneficial insects than it will detrimental ones. Killing all the beneficial insects in your garden can only guarantee yourself lots more pests and no garden.

Each crop/food a a few pests specific to it and it is a simple thing to learn what those are. A Google search using "common pests of _______" (insert name of the vegetable) will give you all you need to know about them plus what is available to control them without harming the good guys.

For example, the most common pest of cabbage is cabbage loopers and they are easy to control with Bt dust. Aphids can just be hosed off with a stream of water assuming you aren't inviting them in with excessive Nitrogen fertilizers.

As to "brown beetles" - there are hundreds of them some good and some bad, so first you have to learn to know your bugs.

Dave