We encourage all children to be active to stay healthy. Summer time offers great opportunity to play outdoors which may expose your child to bites from ticks and mosquitos. West Nile virus is one illness spread by mosquito bites. Apart from limiting outdoor activity in times of high mosquito activity (dusk and dawn) and wearing clothing that covers the skin, insect repellants should be used for additional protection.
The American Academy of Pediatrics supports the use of DEET up to 30% concentration in children > 2 months of age. Other repellants include Picaridin (better tolerated on the skin than DEET) and natural materials including PMD (active ingredient in oil of eucalyptus) and IR3535. Products containing citronella and other botanical oils are inferior to all the other repellants listed above and data is limited on use in children.
More parent friendly tips from the AAP can be found here: Safe use of insect repellants