Garden pests: To naturally combat garden pests like nematodes, sprinkle plants and the soil around them with handfuls of sugar. The sugar will feed microorganisms which will increase the organic matter in the soil while making it a hostile environment for nematodes.
Bugs and roaches: Mix equal parts sugar and baking powder and sprinkle the mixture over any place you suspect bugs are hanging out. Sugar attracts the bugs and the baking powder exterminates them.
Wasps: Make a simple syrup by mixing two parts sugar with one-part water and bringing it to a boil. Once it cools, pour the syrup into a jar and set it outside. The sticky mixture will attract the wasps and trap them.