Our most popular general use product for chiggers and other insects is called Talstar. It is widely used by pest control companies because it is labeled for almost every insect you could have a problem with and you can use it outside the home as well as inside, it is odorless and very safe for use around children and pets. It is a liquid concentrate that you mix with water in a pressurized sprayer. It will last for 60 to 90 days outside in between treatments. It is also labeled for lawn and ornamental use, and can be used on trees, plants, bushes and shrubs for all sorts of ornamental pests including Japanese beetles, mosquitoes, and other leaf eating pests.
Here is a link to the product for you to read further. There is a video on this page as well that talks about how to do a general pest control application. There are also many customer reviews left by people that have used this product.