Insect Pest Management | Grassroots Gardens

INSECTS & PEST MANAGEMENT

Insects that feed upon a plant's leaves, fruit, or roots can become a problem if they reduce a crop's yield or seriously damage and jeopardize it's survival. The presence of insects in a garden is to be expected, but when they become a nuisance and endanger your garden's ability to produce food, you may need to begin Integrated Pest Management.

Integrated Pest Management

Cabbage Worms and Butterflies

Green caterpillars feed on the leaves of brassica plants. Butterflies can lay up to five generations in one season.

The most effective, long term approach to reducing insect pests is to use multiple control methods that work best together. This is known as integrated pest management.

1. Monitor the insects in your garden. Many insects are not harmful and even beneficial to have in the garden. Proper identification is essential before deciding on a management approach.

2. Use mechanical and physical controls such as floating row covers and mulches that will prevent insects from accessing their desired plants.

3. Utilize cultural controls like crop rotation, trap crops, and fall garden clean up to reduce insects from targeting or reproducing in your garden.

4. Chemical controls may be needed to combat the most serious infestations. These should be used in such a way in that they do not affect people, non-target organisms, and the surrounding environment.

Leaf Miners

Leaf miners are a larvae that feeds and tunnels inside of the leaves of a host plant.

Cucumber Beetles

Cucumber beetles target most members of the cucurbit family, spreading diseases which will kill affected plants.

Mechanical and Physical Control

Floating row covers are a lightweight, breathable fabric which acts as an insect barrier to vulnerable plants.

They can be draped upon crops or placed over a metal frame. Enough slack should be provided to allow the plants to grow larger.
Covers should be secured to the soil on the sides of plants to prevent insects from entering.
Do not use on crops that have pests which overwinter in soil, as that will trap the insects in with the plants.
Covers must be removed when plants flower if they require insect pollination.

Plastic mulch should be laid directly on the soil several weeks before planting your crop.

Plastic mulch traps heat, which warms the soil and extends the growing season.
The warmth created under the mulch will suppress weed growth and retain moisture.
Plastic mulch will also kill any vulnerable overwintering insects, as well as act as a physical barrier to prevent them from emerging from the soil.

Squash Vine Borer

Squash vine borers tunnel into the stems of all squash and pumpkin plants.

Japanese Beetles

Adult beetles swarm and eat the leaves of a plant while the larvae live in the soil and feed on the plant's roots.

Cultural Controls

Fall garden cleaning helps to reduce the amount of overwintering insects.

Heavily infested plants should placed in the garbage instead of a compost pile.
Diseased plants also need to be removed, or the particles will remain and infect your crop again in the spring.
Lightly tilling the soil in the fall will kill some pests overwintering in the soil.
Native perennial plants should be left standing, as they overwinter beneficial insects and act as a source of food for birds.

Trap cropping utilizes a sacrificial plant or plants on the outer edges of a garden to attract pests away from the main crop.

Plant your trap crop at least two weeks before planting the main crop.
Trap crops should be selected by their attractiveness in regards to the insects that you will target.
The trap crops will allow harmful insects to congregate and feed, where they can more easily be found and destroyed.
Insect pests on the trap crop must be killed and disposed of before reproducing to successfully protect your main crop.

Crop rotation reduces the risk of pest infestation and subsequent disease by disrupting an insect's reproduction cycle.

Plants belonging to the same family are often susceptible to shared pests and diseases.
Planting crops in the same area increases the amount of pests present as they become accustomed to a reliable food source.
Eggs, larvae, and adults will also over winter in the soil, thus being present to attack vulnerable crops in the next year.
Crop rotation also improves soil health, as plants extract and replenish different nutrients in the ground.

Flea Beetles

Young seedlings are most at danger as adult beetles will chew holes through the majority of a plant's leaves.

Squash Bugs

Adults and nymphs feed on all members of the cucurbit family causing stems and leaves to wilt.

Chemical Controls

Bacillus thuringiensis (Bt) is a naturally occurring bacteria that is found in the soil.

Bt produces spores that become a toxic protein inside the insects that consume it, mostly leaf eating caterpillars and larvae.
Use sparingly only on affected crops, as it is toxic to Monarch and other native butterfly caterpillars.
Bt is harmless to birds, fish, and mammals.
Bt degrades in sunlight, it is best applied in the late afternoon and evening.

Neem oil is a natural insecticide extracted from the seeds of the neem tree.

Neem oil is used as a repellent to prevent insects from feeding on a plant's leaves.
Neem oil is non-toxic to birds, fish, bees, and mammals.
Apply about once a week, in the evenings to avoid damaging plants foliage.
Excessive use of neem oil can damage delicate plants, be sure to follow application instructions.

Diatomaceous Earth (DE) is a naturally occurring mineral that is ground into a fine powder.

DE works as an effective insecticide on pests that have an exoskeleton, such as beetles.
It should be applied in the early morning, slight moisture will help it adhere to a plant's leaves. A steady rain however will wash the application away.
DE is harmless to earthworms, but is fatal to bees and other pollinators. Its use should be targeted and applied sparingly.