How can I control flea beetles in my vegetable garden? Ask Extension expert

Starting A Vegetable Garden doesn’t require a lot of money or talent, just the willingness to spend time every day tending and nurturing the plants. It also helps to know what you like to eat and consult a zone chart before choosing seeds or planting seedlings.

Gardening season is underway, and you may have questions. To ask one, simply go to the OSU Extension website, type it in and include the county where you live. A photo is very helpful.

Q: I’ve included a photo of damage to my tomato plant leaves. The plants came from more than one nursery. I rely on my tomato crop for canning and winter use so am very concerned. – Baker County

A: The damage is likely caused by flea beetles. Flea beetles are shiny, oval blue-black beetles, about 1/10-inch long. The larvae are tiny and gray in color. Flea beetles prefer hot and dry conditions. The get their name from the quick hopping motion that they make when they are disturbed.

Adult flea beetles have an appetite for many garden vegetables, including tomato, potato, beet, chard, eggplant, pepper and radish; they are also attracted to marigold and nasturtium.

Adult flea beetles chew leaves, leaving pits or small holes in the foliage. Older plants can withstand some damage; however, younger transplants may dry out and die from the many holes riddling their leaves. Jumping from plant to plant, flea beetles also spread diseases such as early blight and bacterial wilt; tomatoes are often a victim.

Adult flea beetles overwinter in weeds and garden debris and may overwinter in nasturtium vines left standing in the garden. In late spring they lay tiny white eggs under the soil around the host plants. Larvae feed and pupate underground. There are one to four generations per year.

Preventing flea beetle infestations can be helped by cleaning up the garden to remove havens for overwintering adults. Because flea beetle eggs are deposited in the soil, frequent cultivation will cut down on the number of eggs, larvae and pupa in the soil. It is a good gardening practice to eliminate weeds in the garden area, as these insects thrive on them. To protect seedlings in the spring, use floating row covers. Keep garden beds well irrigated in the summer.

Flea beetles shy away from shade. Plant vegetables close together and thin later when flea beetles are less of a threat. Use mulch to keep the ground moist and less attractive to egg-laying adults. Lightly misting the leaves of vegetables under siege may make foliage less attractive to flea beetles. You can kill adult beetles by spraying with an insecticidal soap. Wood ashes repel flea beetles and can be used in two ways: either place a mixture of equal parts of ashes and agricultural lime in small containers around the plants, or simply sprinkle a spoonful of ashes on each plant two to three times per week. – Chris Rusch, OSU Extension

Q: A plant that appeared in my yard is happy and spreading easily, and I don’t know if I can just appreciate it or if it’s invasive and should be removed. It’s in a moist area that dries out in late summer and the plant dies down, to reappear in the early spring.

A: This looks like enchanter’s nightshade, Circaea alpina ssp. pacifica. This is a perennial plant that most likely dies back in winter to return in the spring. It grows 4-10 inches tall and 1-2 feet wide. Windblown seed probably came into your yard last fall.

It has small, white-pink flowers atop stalks and is easy to grow. It is not a member of the nightshade family and from what I found, not poisonous but not necessarily edible either. It is a native and can spread easily.  But it is easily pulled.  Grows in moist areas as you describe. This is a link to Pacific Northwest Flower reference. – Sheryl Casteen

Q: I would like to know how to remove a particular weed out of my kinnickinick – Jackson County

A: I’m afraid the only way to remove invasives like weeds from mature kinnikinnick is by hand. Chemicals will kill the wanted plant along with the weeds. Cultivation by hoe is out because the structure of the ground cover is long soil-level branches, some of which will root along the branch. Get the weeds early so they don’t seed, and you will have less of a problem in the future. – Marjorie Neal, OSU Extension Master Gardener

Q: Do you recommend watering pear and plum trees that are about 10 years old?  — Multnomah County

A: The general rule is that fruit trees need be provided supplemental water only for their first five years, particularly in the Willamette Valley, where clay retains water. However, the amount of water to ensure fruit production varies by species (and, often variety), and the amount of sun they receive during hot weather.

If you see wilting leaves or shriveled fruit, you should water weekly, making certain the area drains, to prevent soil diseases. – Kris LaMar, OSU Extension Master Gardener

Source: oregonlive.com