Courtesy of Wikipedia
Citronella java essential oil makes a good insect repellent, but in our experience all other types of citronella are a bit weak. Lemongrass essential oil easily becomes an insect repellent spray. Be sure to shake it before using it, and reapply every couple of hours.
All-Natural Citronella Insect Repellent
Citronella java essential oil
1 empty spray bottle, 300 ml or 1 oz
1. Make sure the spray bottle is empty and clean.
2. Fill the bottle almost up to the top with filtered water. Leave enough space to add the essential oil.
3. Carefully add 15 − 20 drops of the essential oil to the bottle.
4. Close carefully and shake well before using.
This only lasts a few hours, so be sure to take it with you and reapply liberally whenever you remember to.