A Natural Approach to Pest & Disease Management in the Garden
How frustrating is it to spend a couple of months growing a beautiful cluster of tomatoes or that perfect crisp cucumber only to have a pesky, little insect get to it first? What’s your first reaction when you see that worm eating away at your plant or fruit? Is it to grab the nearest insecticide to get rid of those little pests? STOP! Don’t allow insecticides to be your first line of defense against pest and disease. There are many ways to prevent the detrimental effects of plant diseases and pests and you can be a successful gardener by using these three control methods: cultural, biological and mechanical.
During the planning stages, you will need to be thinking of biological controls. It will save you lots of work if you let nature do your work. Nature provides predatory and parasitic insects which will feast upon the harmful insects in the vegetable garden. When deciding which vegetables to plant include some flowers and herbs to attract beneficial insects to your garden. Follow the guide below to familiarize yourself with beneficial insects, the plants they love and the pesky insects that satiate their appetite.
Green Lacewings
Plants they love: Fennel, Coriander, Cosmos, Coreopsis, Dill, Queen Anne’s Lace, Yarrow, Golden Marguerite & Prairie Sunflower.
What they eat: While the adults feed on nectar and pollen, the larvae feed upon aphids, cabbage worms, whiteflies and caterpillar eggs.
Ladybeetles
Plants they love: Fennel, Coriander, Sweet Alyssum, Coreopsis, Cosmos, Dill, Queen Anne’s Lace, Yarrow, Golden Marguerite, Prairie Sunflower, Marigold, Oregano, Thyme
What they eat: Adults and larvae eat aphids, thrips, mites, mealybugs, scale.
Predaceous Ground Beetle
Plants they love: Statice, Zinnia, Marigold, Lemon Balm, Parsley, Fennel, Gloriosa Daisy, Thyme & rocks to crawl under and gobble up the insects hiding underneath
What they eat: Adults feed on cutworms and root maggots & larvae feed on a slugs, cutworms, caterpillars, potato beetles and asparagus beetles.
Syrphid Fly or Hover Fly:
Plants they love: Zinnia, Cosmos, lavender, golden marguerite, thyme, statice,
What they eat: The adults are excellent pollinators while the larvae munch on aphids, caterpillars & mealybugs
Parasitic Wasps:
Plants they love: sweet alyssum, parsley, marigold, lemon balm, yarrow, allium, thyme, zinnias, fennel, dill, cosmos
What they eat: cutworms, cabbage worms, army worms, coddling moths and butterflies (no insect is perfect but as a garden is developed naturally all elements will fall into their own place).
Don’t forget: Tachinid Flies, Praying Mantids, Spiders, Assassin Bugs, Damsel Bugs
While nature is our biggest ally, sometimes we need to help out a little and this is where the cultural and mechanical methods come into play.
Cultural methods of disease and pest management will include:
– Planting early. By getting squash and tomatoes in the ground by late March or early April, the gardener has a head start on the lifecycle of many pests.
– When purchasing seeds or plants, choose varieties which are resistant to particular diseases and are hardy for the particular USDA hardiness zone.
– Practice good sanitation by removing weeds where pests can abide and removing plants that are no longer producing to alleviate transfer of disease and continued habitats for pests.
– Allow plants the recommended spacing to allow airflow to discourage conditions that are favorable to disease
– Keep watering at ground level so water does not sit on leaves. Wet leaves also creates favorable conditions for disease.
While in the garden, mechanical controls are some of the simplest methods of combatting pesky insects. Observation skills are key to thwarting an attack. Each visit to the garden is an opportunity to discover new things. Unfortunately, sometimes discoveries include finding aphids, squash bug eggs, seeing holes in leaves or noticing insect frass (poop) on leaves. Upon these discoveries, the gardener can take action before the damage overcomes the garden. Aphids can be sprayed with the water hose, insect pest eggs can be lifted off with tape and squished, holes and frass give clues to look for caterpillars which can be fed to birds or handpicked (gloves optional, scissors or a pocketknife helpful). A gardener’s eyes and hands can be the best control against pests.
With proper planning, keen observation and dedication, there are still times when insect pests reach uncontrollable levels. This is the time to decide whether the crop or plant is worth saving. If you have tried spraying with water, the beneficial insects are doing their job but it just isn’t enough, and your hands are tired from squishing, it may be time to use an organic chemical control. When using any spray, all directions should be followed and consideration for beneficial insects such as bees should be taken into account. Using chemical controls in the evening once pollinators have slowed down, when there is no wind, and when plants will not be wet are all responsible steps of using these controls. Bt (Bacillus Thuringiensis) is a bacteria that affects caterpillars such as: army worms, cabbage loopers and tomato hornworms, but keep in mind that butterflies are caterpillars during their lifecycle and these can be affected as well. Diatomaceous Earth can be effective against slugs, fire ants and a number of other insects but can also harm beneficial insects. Neem oil is an oil used in organic gardening to combat aphids, whitefly, hornworms, leafminers, thrips and a host of other insects but again, keep in mind it can be harmful to all of the beneficial insects as well.
As a gardener, doing the least amount of work with the largest reward is a major goal. So, with planting for beneficial insects, selecting disease resistant varieties and varieties for your garden zone, proper plant spacing, proper watering, mulching, observation and handpicking, most disease and pests can be avoided. Keep your garden natural & healthy and you will reap the rewards.
Additional Resources:
Identification of Common Garden Pests
Identification of Common Vegetable Disease