The Ability to Resist Pests & Diseases
From Chapter 20 of "Healthy Garden Healthy You" by Milo Shammas
Pest control starts in the soil. If your soil is healthy and you have diseases under control, plants are far less vulnerable to attack by pests. Also, biodiversity supports healthy soils that keep diseases under control.
Most plant pathogens are fungal. If you limit or remove the environment that fungus loves by making it less favorable, you minimize their ability to thrive and destroy your garden. For example, dark and damp soil with overhead sprinkler systems is the perfect environment for fungus. If there are ample fungal-feeding organisms present in the soil, many of the fungal spores will be eaten before they begin to grow and spread. Well-aerated and evenly moist soil cuts down on anaerobic conditions to help control fungal pathogens and discourage denitrifying bacteria. These conditions simultaneously minimize nitrogen loss from the soil. This all goes back to biodiversity and a healthy balanced soil.
Healthy plants naturally resist pest and diseases in two ways. First, the thicker a plant cell wall, the more it resists infection and insect attack. Secondly, a weak and susceptible plant transmits an electro-magnetic signal in the same frequency range for destructive insects, calling them to come and eat it. Plants grown organically naturally develop steadily and thoroughly as they have access to a more diverse reservoir of nutrients. As a result, they will be stronger and more resistant to pests and diseases. Biodiversity is the key factor. The living variety of organisms in the soil, both micro and macro, helps regulate fungal pathogens and insects. Beneficial nematodes, mites, and mycorrhizal fungi are all great for fighting pest and disease problems.
Controlling pests and diseases is far more important for farmers because of the sheer volume of produce they handle. Pests thrive in the grand opportunity that exists where they can eat or lay eggs in hundreds of acres of plants. The home gardener, with a much smaller crop, has much less concern for large colonies of pests settling into the garden permanently, especially if he grows a wide variety of fruits, vegetables, herbs and flowers.
Plants do not naturally grow to the standards of perfection (no spots and perfect complexion) we see in a supermarket produce section. Rather than trying to eradicate all weeds, diseases and pests, we can manage them in a way that is non-toxic, sustainable and gratifying. Some diseases and pests, however, are quite abundant and cause problems for gardeners. You have many different treatment approaches other than using commercial chemicals. Don't be misled to thinking high yields and quality demands exterminating all pests, diseases and weeds with chemicals. By taking an organic approach, you can manage the complex functioning of nature that has sustained life for hundreds of millions of years. With organic methods, you can support a diversity of life in your garden.
Approaches to Managing Pests and Diseases
The first step is to grow strong and healthy plants. Not all conditions warrant the use of insecticides or fungicides. If just a few caterpillars or slugs are crawling around on the leaves, you can physically pick them off the plants. As we have said many times, overuse or misapplication of pesticides and fungicides seriously disrupts the biodiversity in the soil and affects the phytotoxicity of the plant itself. Also, pests can become resistant to the treatment. You then need to apply even more chemicals to achieve similar results. Repeatedly applying more toxic chemicals perpetuates an uninhabitable environment so toxic that no life can survive in it. Consider some alternatives.
Natural Chemical-Free Methods
Natural methods manage and prevent harm to plants by pests or diseases without resorting to sprays. The first step is to identify the disease or pest and when they are active. Then we can devise a way to minimize the damaging effects. Here are a few.
Remove pests by hand or rinsing. Some pests crawl along leaves, eating them or using them to lay their eggs. Catching and removing pests early, while requiring more labor, can prevent exponentially escalating problems. Some pests, like slugs and snails, are more active on damp nights, while others are active during dry sunny days. Some pests can be rinsed off plants with a powerful stream of water. Attachments that hook up to your hose are designed to blast bugs off foliage. Removing pests by hand or rinsing is better than spraying, especially near ponds, streams or lakes, since pesticides can injure or kill aquatic life.
Remove badly infested or diseased plants to minimize spreading to healthy neighboring plants. Put infested or diseased plants in a closed plastic bag and remove them from your property to minimize contamination.
Install barricades. There are a few different types of barricades. If you want to protect smaller plants from birds or animals, construct a small frame around the plant and enclose the area with mesh netting. You can also cover groups of fruits with pantyhose or tights to stop insects or birds from feeding on your freshly ripe fruit. Placing cut-off plastic bottles around smaller plants will help protect and warm up the soil around the roots to promote microbe activity. Row covers made from material with small holes can protect entire rows from birds, beetles, bad worms and maggots. Cabbage maggots like to lay their eggs in the soil right around plants. You can deter them by placing a collar made of cardboard or some other fabric around the stems. This causes females to lay their eggs on the collar where the eggs will dry out before hatching.
Pheromone traps can attract pests to monitor when they will be most damaging. Pheromones are gaseous chemicals that insects and animals use to communicate with each other, locate plants or find a mate. For example, by trapping certain insects, you can determine the best time to apply a pesticide to stop the offspring from causing plant damage.
Sticky traps used in various locations can stop pests in their tracks. Non-flying insects travel up and down plants such as trees. Placing a sticky band around, but not touching, the tree trunk will keep these pests from reaching their destination. You can also place other sticky bands around containers to stop bugs like ants or earwigs. Traps can be hung above plants in greenhouses to capture flying pests. This step indicates the extent of the invasion. Additional controls may further deter plant damage. Other traps such as half-full cans of beer can be buried at soil level near plants to attract slugs and snails. They fall in, get drunk and drown.
Repellents usually deter birds, deer, rodents and moles by using bothersome smells, tastes or noises these animals don't like. Soaps, oils and noise repellents are available at some nurseries. For getting rid of moles or gophers, try this trick. At your local barbershop, ask for some cut hair they normally sweep up and throw away. Place the hair in the rodent's hole. Gophers and moles will perceive a human is down there with them and be repelled from your garden. Buried hair also breaks down into nitrogen-rich fertilizer.
Biological Pest Control Tactics
These involve recruiting the help of pest predators or spraying pests with living organisms. Remember biodiversity checks and balances, but if the balance is off, you can use these techniques Releasing pest predators like ladybugs and praying mantis are a good approach. Planting flowers and other shrubs around the garden can attract and provide shelter for pest eaters such as birds, frogs, toads, bats and certain insects. This is called companion planting.
Having a small body of water, like a pond, nearby will provide a breeding ground for creatures like frogs and toads. If you add pest predators, avoid following it with an insecticide, which can kill off the predators and be a waste of money. If you must spray, do it first, and release predators a few days later.
Beneficial microbes -- Bt, or Bacillus thuringiensis -- are a great and safe way to control lepidopteron larvae, or caterpillars, as they are commonly known. This is considered one of the most effective ways to get rid of leaf-chewing pests. Different treatments have environmental conditions under which they operate best. For instance, Bt is less effective when applied in direct sun. Caterpillars feed only in warm weather, so apply Bt when it is warm, but not in direct sun to maximize its potential. Early morning is the best time to apply.
Botanical sprays use essential oils like cinnamon, clove, mint, rosemary, eucalyptus and wintergreen oil to kill and control a wide variety of pests. These substances kill by blocking chemical signals that control body functions. Basically, the substances immobilize insects. Botanical oils are completely derived from plants and break down in the environment quickly to harmless substances that do not persist or cause environmental damage.
Garlic extract is also a great option to repel pests. Garlic fools pests into thinking they are on the wrong plant. Most pests smell receptors are located on the bottom of their legs. When they land on a plant that has been sprayed with essential oils or garlic, it smells different from their target plant, and they move on to neighboring plants.
Use these as a last resort when nothing else has worked. If you have a biologically diverse garden, you may never need a toxic chemical to control pests or disease. However, if you do use chemicals, read the label carefully and never over apply. More is not better.
I do not like chemicals around my home. The very nature of using a chemical on the healthy garden defeats what we have discussed. I don't recommend any specific chemical treatment. If you choose a chemical treatment, remember that pests develop resistance to pesticides, requiring stronger and more frequent applications to be effective. Toxic pesticide use may be detrimental to the environment and severely disrupt the balance of living organisms in the soil. Pesticides are also severe pollutants of ground water, lakes, rivers and oceans. While more detrimental on the large-scale farm, backyard pesticide use can also damage the environment.
To Spray or Not to Spray
Unfortunately, in some cases we don't have a choice between using chemical treatments and letting nature take its course. If you must spray to save the garden, employ one of the methods discussed above. When infestation grows out of control, the only quick way to get rid of pests may be to get out the extermination sprays to salvage plants. Fortunately, some well-developed treatments have minimal side effects when used properly.
Any chemical agent controlling insects and disease should be used as a last resort and in modest amounts. Repeatedly using the same treatment leads to pest resistance. Avoid it by switching treatments. Pay close attention to the plant toxicity of each method to avoid killing the plants you want to salvage. Never spray a plant with any treatment in direct sunlight. Even the safest of treatments can be harmful if applied in direct sunlight.
Treating plants is sometimes like treating people. Often a physician will treat a symptom rather than diagnosing a cause. A doctor can tell you to take a pill to mitigate a symptom, or he can tell you to watch your diet and exercise to prevent heart disease. The same symptom and disease relationship holds true for plants. If the soil is healthy and full of bio-diversity, you can prevent disease instead of treating symptoms.
Milo Lou Shammas
Founder and Formulator