What dangers lurk in your backyard? Especially for young children, the risks range from the obvious (mowers and tractors) to the unexpected (poisonous plants). Here are the major danger zones--and how to minimize your child's risk this summer: 1. Lawn mowers. Children are involved in some 68,000 mower injuries in the U.S. each year. The grisly tally includes deep cuts, burns, loss of fingers and toes, crushed and broken bones, and even amputations. Thrown rocks and other projectiles are also a hazard, since mowers can eject a piece of metal or wood up to 100 miles per hour. Then there's the risk of gasoline that powers most mowers: A recent study cited in Pediatrics logged 65,756 calls to regional poison centers and an estimated 40,158 emergency visits from 2000 through 2009 for gasoline and other fuel-related injuries, mostly to boys between 1 and 2 years old and during the summer months. To childproof your mower: Store mowers and all power equipment in a locked garage or shed.Keep kids indoors while mowing--and never let them "ride along" if you use a tractor or riding mower.Keep gasoline and motor oil safely out of children's reach. Safeguard older kids, too: The Children's Hospital of Philadelphia recommends that children be at least 14 years old to operate a walk-behind mower--and at least 16 for tractors and riding mowers. Supervise them if they're sharing the mowing duty--and be sure they're wearing both eye protection and ear protection, since most mowers are loud enough to cause hearing damage. 2. Pesticides. A recent Environmental Protection Agency study found that almost half of all households with children under five had at least one pesticide stored in an unlocked cabinet within reach. These same substances can be toxic if inhaled or swallowed, and can pose risks if they get in a child's eyes or are absorbed through the skin. Children are also at risk if they touch grass or plants that contain pesticide, herbicide, or fertilizer and put their hands in their mouths. And while pesticide exposures make up a relatively small percentage of child deaths by poisoning, they can have lasting effects on neurological systems. To child-proof yard chemicals:Store all chemicals in a locked cabinet safely out of children's reach. And never transfer them to cups, bottles, and other food or drink containers that can be tempting for kids. Before applying pesticide, be sure children, toys, and pets are away from the area--and keep them away for at least 48 hours after you're done. Also consider using non-chemical pest and weed controls, such as a dandelion fork that removes both the plant and its root. 3. Plants. Believe it or not, plants are a leading cause of poisoning for children under five. And despite their innocent-sounding names, Lily of the Valley, foxglove (a.k.a. digitalis), oleander, and azalea are toxic. To childproof your plants:Consider fencing off toxic plants--or removing or avoiding such plantings altogether. (For a list of poisonous plants common to your area, call your local poison control center.)With any plant, keep a close eye on children when outdoors. Keep the Poison Control Center number (1-800-222-1222) in and near your phone, prominently visible to all caregivers. 4. Bugs. Most reactions to bees and other stinging insects are mild, but severe allergic reactions can be deadly and can occur even if after previous stings that caused no harm. Some tick bites can lead to Lyme disease, while disease-carrying mosquito bites can lead to West Nile virus. To help keep your child from getting "bugged" this summer: Don't use scented soaps, perfumes, or hair sprays on children, and avoid dressing them in bright colors or flowery prints. Keep insect-attracting features like bird baths and other stagnant water out of your yard. (You may also have to choose between bugs and lush flower gardens, which typically attract them.) Keep food covered during picnics. Use insect repellents containing DEET on children 2 months and older. The American Academy of Pediatrics and Centers for Disease Control recommend repellents with no more than 30% DEET. If your child is stung, and you can see the stinger, remove it by gently scraping it off horizontally with a credit card or fingernail. See our report on how to accident-proof your yard for related information.