First off, put a fence around your garden to keep out rabbits and deer. If you know that rodents will be a problem, you may even consider sinking your fence several inches into the ground to help prevent tunneling. Bird netting is useful against, well, birds; but also discourages rabbits and deer.You can also mix one tablespoon of liquid dish detergent and one tablespoon of hot sauce with a liter of water, and spray it on the threatened plants. Or, hang a bar of fragrant soap near the plants deer like to eat. The fragrance of the soap will repel the deer.
Pyrethrin insecticide, by itself or in mixed with other compounds, is a very effective, family-safe and environmentally-friendly insecticide.
About 200 years ago people in central Asia discovered that dried/crushed flowers of certain chrysanthemums were toxic to insects. During the Napoleonic Wars this "insect powder" was used to control flea and body lice infestations by soldiers. Since then, pyrethrum has been used in many forms for effective, low toxicity insect control. Pyrethrin is the active ingredient in pyrethrum that kills insects and that is the chemical you will see listed on insecticide labels.
Spinosad is an insecticide based on chemical compounds found in the bacterial species Saccharopolyspora spinosa. It is a relatively new insect killer that was discovered from soil in an abandoned rum distillery in 1982.
After ingesting Spinosad, insect pests die within 1 to 2 days. Will NOT persist in the environment and is classified as an organic substance by the USDA National Organic Program (NOP).
Neem oil is a naturally occurring pesticide found in seeds from the neem tree. It has been used for hundreds of years to control pests and diseases. Neem juice and oil contains more than 50 different pest-killing compounds, so even insects with immunity to some substances cannot build up enough resistance to all the compounds. Neem’s effects are strongest on young insects, particularly those that grow rapidly such as squash bugs, Colorado potato beetles and Mexican bean beetles.
For soft-bodied insects (aphids, thrips, whiteflies, spider mites, immature leafhoppers, etc), look for natural sprays that have an insecticidal soap as the main active ingredient. Insecticidal soap is a fatty acid derived from animal fat; it’s not a detergent like household soap. When sprayed directly on an insect, it weakens the cellular structure of the insect’s exoskeleton, causing it to die. Some plants have adverse reactions to insecticidal soaps so you should test out the soap on a small portion of the plant and wait 48 hours to see how the plant reacts. It’s also advisable to avoid spraying plants in the heat of the day.
Diatomaceous earth can be used in the garden to make life difficult for newly emerged Japanese beetles or cutworms. In dry weather, DE spread beneath plants will kill slugs. DE becomes less effective when wet and is most useful in dry situations — for example, puffing it into crevices where cockroaches have been seen or using as a flea dust on pets. More about DE here.
Use sticky traps for mature insects. You can buy or make colored sticky traps that target specific pests. To make a sticky trap, paint a 4’’x6’’ piece of rigid material the desired color. Cover the trap with a clear plastic bag or plastic wrap and then coat the plastic in a sticky substance, such as Tangle-Trap. When a trap is covered in bugs, replace the plastic and recoat with the sticky substance. Traps should be placed plant-height every 3-5 feet. A mix of white traps and yellow traps are said to attract many common insect pests, such as whiteflies, cucumber beetles, winged aphids, and leafhoppers.
Here’s an all-purpose spray for leaf-eating insects, if you’re a DIY sort of person. Please note that this recipe contains garlic, onion, and hot pepper and so can irritate eyes and skin; use appropriate protection when mixing and applying. The spray can be stored in the fridge for up to a week. As with all pesticides, it’s a good idea to spot test on a leaf before applying to entire plant. Also, there are many variations of this recipe, so you may find one with a different ingredient ratio that works better for you.
· Chop 1 garlic bulb and 1 small onion in a blender
· Add 1 tsp of powdered cayenne pepper
· Add mixture to 1 qt of water and steep 1 hour
· Strain liquid through cheesecloth and add 1 tbsp of liquid dish soap
· Put liquid in spray bottle and shake to mix
· Spray onto those pesky bugs!