How to manage these 5 garden pests
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Tomato hornworms are large caterpillars with a horn-like tail. They feed on solanaceous weeds, specifically tomatoes, eating on the leaves around the top of the plant.
While hornworms are typically found on tomatoes, they can also be found on potatoes, eggplant and peppers. Larger, older hornworms can destroy fruit and many plant leaves.
To manage, examine plants a minimum of two times a week during the summer. Small tomato worms are a yellow to white color, and large caterpillars have eight v-shaped marks on each side with a protrusion that resembles a horn on its tail end.
Managing garden weeds and tilling the soil after harvest will help decrease the chance of infestation. You may handpick the hornworms from infested plants and throw them in soapy water to kill them. The insect is fairly easy to spot because of its large size.
If the following treatments do not work, click here for a list of common insecticides to control tomato hornworms.Date Published: June 29, 2015Date Updated: June 29, 2015
With approximately 4,000 species worldwide and 1,300 occurring in North America, aphids are one of the most common insects found on garden plants.
The green peach aphid, potato aphid, cabbage aphid, melon aphid and brown ambrosia aphid are some common aphid species. The green peach aphid, alone, feeds on hundreds of plants, including potato, pepper, cabbage, spinach, asparagus, aster, dahlia, iris and verbena.
Aphids are about one-eighth of an inch long, and have pear-shaped bodies that vary in color from black, green, red, pink, brown or gray.
Damage to plants range from off-color foliage, twisted leaves and poor plant growth. Feeding aphids secrete excess sugars from their abdomen and form a sticky substance known as honeydew. This environment promotes growth of black sooty mold, which reduces the photosynthetic area of the leaf and, as a result, produces smaller fruit.
Aphids are also carriers of numerous viruses that can infect vegetables and cause mottling, yellowing or curling of leaves and stunt plant growth.
Regularly examine leaves and stems for aphids throughout the growing season.
Spray water from a garden hose to rid plants of aphids and to help wash away the honeydew or sooty mold. Lady beetles are known predators of aphids, along with lacewing larvae, syrphid flies, aphid midges and species of small, stingless wasps.
Click here to learn more about aphids and treatment options.Date Published: June 29, 2015Date Updated: June 29, 2015
Leafminers are insects that feed within leaves and produce large blotches or mine-like tunnels. Vegetable leafminers and spinach leafminers are popular leafminer species. Adults of both species are small flies and overwinter as pupae in the soil.
Vegetable leafminers create serpentine mines that wind across the leaves. Spinach leafminers are black and yellow, and produce round-shaped mines on the plant.
The spinach leafminer generally feeds on spinach, Swiss chard, tomato, cucumber and celery. The vegetable leafminer feeds on bean, eggplant, pepper, potato, squash, tomato, watermelon, cucumber, beet, pea, lettuce and many others.
Leafminers don’t harm plant growth, but are very destructive to vegetables grown for edible greens.
Check young seedlings for leafminers. It is not necessary to treat spinach leafminers when they are attacking the leaves of root crops, such as beets, where the edible portion is not affected. Natural enemies usually keep vegetable leafminers from causing damage.
To combat leafminers, remove weeds, such as lambsquarter, that leafminers can feed on. Dispose of infested leaves when mines are small to prevent further damage, and till your garden after harvesting to destroy pupae.
Click here to learn more about floating row covers and appropriate insecticide use to control leafminers.Date Published: June 29, 2015Date Updated: June 29, 2015
Adult cabbageworms are white butterflies with black spots that can be seen fluttering around plants during the day. Caterpillars are green with light yellow stripes, and are one inch when full-grown.
Imported cabbageworms overwinter in the upper Midwest and start appearing in gardens around May. They are a problem for the remainder of the season.
Cabbageworms feed between the large veins and midribs of cole crops, which includes cabbage cauliflowers, broccoli, kale or collards. Younger cabbageworms create small holes in leaves, while larger caterpillars chew large, damaging holes. They also leave large amounts of fecal matter when feeding.
To manage, check cole crops for cabbageworms soon after planting and inspect plants once a week. It is recommended to check plants more diligently as the season progresses, looking at both sides of the leaves for feeding damage.
To help eliminate the possibility of overwintering, rid the garden of crop residue after harvest. Try to minimize weeds such as wild mustard and peppergrass of the Brassicaceae family since they are alternative hosts for cabbageworms.
Handpicking the caterpillars is an effective control method. You can kill the cabbageworms by dropping them in a pail of soapy water. Floating row covers will help prevent adult moths from laying eggs on the plants. You can drape lightweight all-purpose garden fabric directly over plants or over a support structure, such as metal hoops or wooden frames.
Natural remedies for the caterpillars are paper wasps, parasitic flies, wasps, and pollinators such as bees and flies. You can also use low-impact insecticides such as neem and spinosad. Click here to read more about cabbageworms and treatment options.Date Published: June 29, 2015Date Updated: June 29, 2015
Slugs feed on leaves and seedlings, and they will feed on fruits and vegetables later in the season.
Slugs are particularly damaging in moist conditions. They chew through plant tissue and create holes in plants. The extensive feeding weakens the source, causing plant stress or death.
Slugs overwinter as eggs and hatch in spring or early summer. They can lay eggs throughout the summer, given the right conditions. Slugs tend to be more active at night due to their preference of cool, shaded environments. Warm, dry conditions are less favorable to them.
If you have a slug problem, it is recommended that you rake your garden in early spring to remove leaves, plant debris and slug eggs. Also, water your garden only when necessary, and irrigate in the morning so plants are dry by evening.
You can trap or handpick slugs as a management practice. You can also create a barrier with copper strips or tape sold specifically for slug control. Beetles, toads, snakes, turtles, shrews, ducks, starlings and other birds are natural enemies of the slug.
Click here to read more about slug control and management practices.Date Published: June 29, 2015Date Updated: June 29, 2015
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