To fight maggots already present and to prevent infestation, add beneficial nematodes or rove beetles to your lawn's soil. You can purchase these maggot-enemy insects at garden supply stores. You may also buy diatomaceous earth at garden or farm stores. This product repels maggots when dusted on plants.
To prevent maggots from returning after you treat them, remove any dead plants in your lawn area. Do not use these plants for compost. Either burn them or deposit them in the trash to be removed.
Some insecticides/pesticides are effective at preventing maggots in your lawn when applied at the beginning of spring. Be aware, however, that they may also kill insects beneficial to your lawn. If you use these products, only purchase registered insecticides and read the labels carefully. Questions about these chemicals should be directed to your local university extension program.