As I said in a previous post, I'm sharing a huge list of homemade remedies for your garden. Most of the ingredients you already have them available at home.
Homemade oil spray for insect control on plants:
Mix 2 tbsp of cooking oil, and 2 tbsp of baby shampoo in a gallon of water.
This remedy controls insects like: aphids, spider mites, thrips, whitefly, lacebugs, scale and mealybugs.
Note: DO NOT SPRAY IN SUN! Also, this may injure hairy or waxy-leaved plants like squash and other crucifers. DO NOT use oil on orchids. Thorough coverage of the pest is necessary so spray both sides of the foliage until it drips from leaves. Test spray on a small area of the plant, wait 2 - 3 days and check for damage. It's always a good idea to water the plant the day before you spray. Spray every 5-7 days as needed.
If a fungus is also present then add to the above formula 2 tbsp of baking soda and shake well before and during application.
If the weather is humid or the treat of disease is high, spray every five to seven days. Spray both sides of the leaves thoroughly at the first sign of disease. Always test any spray on a small area of the plant. this solution can be used against blackspot and mildew on roses, powdery mildew on summer squash, early blight on tomatoes, and alternaria leaf blight on melons.
I hope you can put in good use this tip for your own garden.