Your Garden is a small part of a complex interactive mechanism. In an idealistic scheme of nature, all elements interact which one-another in a symbiotic fashion, the existence and actions of one member of the chain, such a the aphid that is sucking on your tomato plants, will ultimately and idealistically benefit the whole scheme of nature.
That 'scheme of nature' concept really doesn't go very far when it doesn't work to our advantage, after all we are on top of the food chain - not the bugs. We want that Tomato in our sauces and salads, not in the biomass of the local insect population.
Humans have devised a multitude of methodologies to eradicate insects who beat us to our crops. Unfortunately - over time , as the ultimate thinking organism, I believe as a whole we've come to the realization that the results of our pro-longed combat with the bug population has worked it's way through the eco-system and we have endangered our own species with the 'friendly-fire' of Chemical pesticides.
The natural interactions within nature are a much more efficient method of controlling the micro eco-systems of our Gardens and Landscapes. It requires quite a bit more strategic thinking than blanket bombing the terrain with DDT or other toxins.
Anise Host for predatory wasps . Deters pests from brassicas by camouflaging their odor.
Artemisia Also known as Wormwood, it produces an antiseptic, and an aroma that repels most insects. It will also deter rodents. Using Artemisia in flower borders is suggested, but not in vegetable gardens because it produces a botanical poison as well.
Asparagus - A substance called asparagin in asparagus repels certain tomato pests.
Basil -The oils in basil are believed to repel mosquitoes, thrips, and flies.
Planting basil with tomatoes is a practice of many gardeners, the drawback being that Basil and tomatoes use similar nutrients at roughly the same time so the basil will actually draw some nutrients needed by the tomato plants and vice versa.
Bee Balm - AS its name indicates, it attracts bees - much needed pollinators to the garden.
Borage - It repels pests such as tomato hornworms and cabbage worm and attracts beneficial bees and wasps. It also adds trace elements to the soil. This is an annual, but generally regenerates yearly from seed. Borage also adds beneficial trace elements to the soil.
Calendula - Old World plants of the Aster family. Often referred to as Pot marigold, it repels Grasshoppers.
Catnip repels aphids, fleas, Japanese beetles, squash bugs, ants, some beetles and weevils. AS you already know it will attract cats.
Chives - Chives will repel Japanese beetles and carrot rust flies among other pests. There is some evidence that chives will help prevent scab when planted among fruit trees. Chives and related plants are said to stunt growth in Asparagus and broad beans.
Chrysanthemums - Pyrethin is an all natural insecticide derived from Chrysanthemums . Control ticks, silverfish, lice, fleas, bedbugs, roaches and ants White flowering chrysanthemums deter Japanese beetles and kills root knot nematodes.
Dahlias also repel nematodes and the blooms look great.
Dead Nettle - Repels Colorado Potato Beetle
Dill not only makes for a great pickle it is useful when planted with cucumbers and onions and in the cool season with lettuce. It attracts hoverflies ,predatory wasps and tomato hornworms . If you plant Dill at a safe distance, it can be used as a trap crop drawing the hornworms away from your vegetable garden.
Four O'Clocks - A favorite food of Japanese beetles. Its leaves are toxic and kills the Japanese invaders. Four O'Clocks are also poisonous to people and pets.
Garlic planted near roses repels aphids. It also deters codling moths, Japanese beetles, root maggots, snails, and carrot root fly.
Hyssop - Hyssop is great for attracting honeybees to the garden.
Lavender - Lavender is a favorite among many beneficial insects and also repels fleas and moths.
Marigolds - Probably the most well known plant for repelling insects. French marigolds repel whiteflies and kill bad nematodes. Mexican marigolds are said to repel destructive insects and rodents. You should choose a marigold variety that is naturally scented to work as a repellent. Although this plant drives away many harmful insects, it does attract others.
Nasturtiums -They repel some varieties of aphids, whiteflies, squash bugs, and cucumber beetles. The yellow blooming varieties attract aphids and can be used as a trap crop.
Petunias - They repel asparagus beetles, leaf hoppers, aphids, tomato worms, and many other pests.
Sunflowers - They draw aphids away from my other plants. Ants move their colonies onto sunflowers.
Ants are among the most difficult insects to control . Many of the 'softer', ant-specific pesticides have proven no match for them as they quickly develop a resistance. Some farmers will use poison-tainted molasses to control ants. Herbal Deterrents for Ants include Mint, Catmint, Tansy, Southernwood, Garlic, Pennyroyal, Spearmint
Aphids are Yellowish-pink to pale green plant lice that suck plant juices. They are a soft-bodied, oval/pear shaped insects and are commonly found on nearly all varieties of plants, vegetables, field crops, and fruit trees. They range in size from 1/50 to 1/4 inch, Some are winged, some are not. An interesting note about aphids is that they are actually "farmed" by Ants , who will often protect them in much the same way a rancher will protect his livestock from wild predators. If you have an ant & an aphid problem be advised that the ants will often attack predator insects such as Lady Bugs, so you will need to control both the ants and aphids. Ants will carry aphids into trees and consume ripening fruits . This can be prevented by applying a band of sticky material around the trunk.
Herbal Deterrents for Aphids include Nasturtiums, Basil, Wormwood ,Spearmint, Southernwood, Pyrethrum/Chrysanthemums, Onions, Stinging Nettle and Garlic.
Predatory Insects of Aphids are Lady Bug and Green Lacewings. Neem Oil is a botanical insecticide with low toxicity ratings that offers a broad range of insect control.
Army Worms Populations of Army worms and closely related species can be controlled to a certain extent with the use of Beneficial Nematodes and Neem
Cabbage Looper - Herbal Deterrents Marigold, Rosemary, Mint, Southernwood, Dill ,Sage, Hyssop, Garlic. Predatory Insects -Praying Mantis . has proven effective as well
Cabbage Worm - Marigold Rosemary Mint Garlic
Carrot Rust Fly Herbal Deterrents - Chives - Predatory Insects Praying Mantid , Lady Bug
Colorado Potato Beetle Predatory Insects Lady Bug
Corn Borers Herbal Deterrents Marigold Radishes Predatory Insects Lady Bug
Fleas Herbal Deterrents - Tansy Lavender Pennyroyal Wormwood Spearmint Fennel. Predatory Insects - Beneficial Nematodes
Flies Herbal Deterrents Tansy Basil Rue Wormwood Eau de Cologne Basil Pyrethrum Predatory Insects Fly Parasite
Fruit Fly - Herbal Deterrents Tansy Rue Southernwood Pyrethrum Predatory Insects Fly Parasite
Grasshoppers- Herbal Deterrents Horebound and Calendula.
Japanese Beetles the best recommended defense against Japanese Beetles is Bacillus popillae, which causes the disease "milky spore " in the grubs while they are still in the soil, and is harmless to Humans and most other species.
'Four O'clocks' are sometimes recommended - they do not deter Japanese beetles, they attract them, but the beetles are killed by it's poisonous properties .
White flowering chrysanthemums are effective. Garlic, larkspur, tansy, rue, white geranium, chives all possess deterrent qualities against Japanese Beetles.
Pheromone based lures and traps are discouraged as they only serve to attract more beetles to your garden/yard from surrounding areas.
Leaf Miners are not a specific species of insect, but comprise an array of various insects that are classified as "leafminers" due to their behavioral traits.
In many cases what is effective against one genus of leaf Miner may be wholly ineffective against another.
Mealy Bugs - Green Lacewings Are the only real effective organic control of this pest
Mosquito - Herbal Deterrents - Lavender, citronella Grass, Tansy, Basil Pennyroyal, Garlic.
Moths - Herbal Deterrents Marigold Lavender Sage Mint Rosemary Southernwood, Thyme Pennyroyal Wormwood Pyrethrum flowers Spearmint Santolina . Diatomaceous Earth is effective against most worm/larva stages. Predatory Insect- Praying MantisHighly effective against moth stages
Spider Mites Herbal Deterrents - Marigold OnionsPredatory Insects Green Lacewing. Other Bio Based Controls include Neem Oil
Slugs and Snails can be deterred with 3-5-inch copper fencing. The copper reacts with the slug's unusual body chemistry to create a "non-lethal electrical charge" in the slug's body . It is not recommended spreading salt about garden areas as it can destroy the soil structure. Snails generally avoid borders of lime, or ashes. Herbal Deterrents - Wormwood
Thrips Herbal Deterrents Marigold Basil. Other Bio Based Controls - Bioneem - Predatory Insects Beneficial Nematodes, Green Lacewing Tomato Horn worm - Herbal Deterrents Borage Wormwood
White fly - Herbal Deterrents - Nasturtiums Basil Other Bio Based Controls Neem Oil