Natural Insect Sprays for Watermelons

Flushing with Water

• Watermelons belong to the same family as other melons, cucumbers, pumpkins and gourds. Besides doing damage to the plant itself, insects often carry diseases that infect the watermelon plant, causing fruit development and other problems. Some insects attracted to watermelon include melon thrips, aphids, mites, silverleaf white fly, cucumber beetles and rindworms. The most natural way to kill insects is with a hard spray of water. Flushing with a forceful spray often knocks insects off the plant altogether.

Stinging Nettle Spray

• One well-known insect spray is made from stinging nettles, a pesky weed gardeners often try and get rid of. Stinging nettle spray is made from a composted tea. Harvest up to 1 quart of nettles, place in large pot, cover with water (rainwater if you have any) and steep the tea for up to three weeks. Mix one part of the tea with seven parts of water. Fill a plastic spray bottle and spray on affected plants. Nettle spray works on aphids and thrips.

Rhubarb Spray

• Take six large rhubarb leaves and place in 2 to 3 quarts of boiling water. Let the tea cool. When cool, use directly in a spray bottle on affected plants; do not dilute. Rhubarb spray works on aphids and June beetles, as well as black spot and fungus diseases.

Pyrethrum Spray

• Extracted from the flowers of chrysanthemums, pyrethrum is a powerful insect repellent. When using such repellents, always work with gloves and wash your hands afterward. Place 2 quarts of water in a pan and bring to a boil. Turn off the heat, add 1 tbsp. of dry flower heads and allow the solution to steep. When cool, fill a spray bottle and spray on watermelon plants. Pyrethrum spray works on a variety of sucking and chewing insects.

Mullein Spray

• To kill white flies, place five parts water to one part mashed mullein leaves and let steep. Allow to cool and spray on watermelon plants.

Warnings

• Botanical insecticides are often more potent and toxic than common synthetic garden pesticides. Use care when handling. Avoid inhaling, ingesting or absorption through the skin. Wear gloves and a filter mask when working with botanical insecticides. The Environmental Protection Agency regulates the sale of botanical insecticides; take the same care when working with botanical sprays you make yourself.