Insects: The Good, The Bad, The Ugly
Gardeners who use organic practices may know not to use certain pesticides or particular fertilizers but knowing why not to use particular products is most beneficial in making future planning and planting decisions in the natural vegetable garden. Not only do pesticides harm the insects wreaking havoc on your garden but they, also, kill the beneficial insects that are helping keep the harmful insects at bay as well as the essential pollinators. And chemical fertilizers can cause an accumulation of salt in the soil disrupting a hospitable habitat for worms & beneficial microbes. Sticking to organic materials in the garden is the first step in creating less work for you, the gardener, and allowing mother nature to do her best work.
Beneficial Insects (The Good!)
Take advantage of beneficial insects role. There are predatory insects which eat the eggs, larvae or adults of insects which eat your veggies. By being able to identify these insects, you can save yourself a lot of heartache. During planning stages of your garden, make sure to buy plants for the insects too. There are many beautiful flowers and herbs that can be incorporated into the garden which will attract these beneficial insects.
Green Lacewings
– Plants they love: Fennel, Borage, 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:
White cocoons of wasp larvae emerged from tomato horn worm
– 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).
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Don’t forget: Tachinid Flies, Praying Mantids, Spiders, Assassin Bugs, Damsel Bugs
– Plants they love: Parsley, thyme, lemon balm, golden marguerite
Garden Pests (The Bad)
Many of the common garden pests you will find munching on your plants in the spring and summer can be dealt with by planting for and introducing the beneficial insects listed above. But identification of garden insect pests especially their eggs can help thwart the attack on your plants. Most insect eggs are found on the underside of leaves. Regular inspection of your garden plants allows you to discover eggs before they hatch and pose a problem.
Squash Vine Borer:
SVB ruins the vascular system of the plant which causes the plant to wilt. Remove eggs. At first notice of yellow excrement on stem, make an incision and remove the larva. Remove infected plants from garden so moths are not able to pupate in the garden soil.
Gardener Tip: Butternut Squash has shown a resistance to Squash Vine Borer
Squash Bugs
Squash Bugs are difficult to catch as nymphs or adults. They scurry away quickly if disturbed. The eggs, however; are shiny, coppery clusters generally laid on the underside of leaves. They are easy to squish or pick up with a piece of tape. Trap squash bugs by laying out boards or pieces of newspaper. Squash bugs will congregate under the boards at night, and then can be collected and destroyed in the morning. Squash bugs are usually only detrimental to cucurbits as young seedlings. They can produce the stippling seen on the leaf above on tomato fruit.
Tomato Hornworm
The pupae are large and not buried very deeply in the soil. Regular soil tillage helps with control. Hand picking and destruction of larvae is often practical in the home garden. Parasitic wasps are also a predator.
Biological Controls
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. Familiarize yourself with beneficial insects, the plants they love and the pesky insects that satiate their appetite.
Mechanical Controls
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 squished with your hands (gloves optional, scissors or a pocketknife helpful). A gardener’s eyes and hands can be the best control against pests.
Cultural Controls
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.
These are just some of the more common garden pests and beneficial insects but there are many out there. Regular tilling, planting a diverse garden with plants to attract pollinators and beneficial insects, limited use of pesticides, use of organic fertilizers, creating a soil full of microbes & mainly regular observation of your garden plants are key to a natural garden that you let Mother Nature do all the hard work.
*Class discussion of Bacillus Thuringiensis, Spinosad, Neem Oil & Diatomaceous Earth*