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Pickling time is soon upon us and so is bacterial wilt. The wilt is one of the most common diseases that infect cucurbits (the cucumber family). Cucumber wilt is most severe in cucumbers, but can also infect muskmelons, squash, pumpkins and gourds.

In cucumbers, the first symptom of wilt is a distinct bronzing of individual leaves, followed by wilting of adjacent leaves and then collapse of the entire plant. You can't cure plants that have bacterial wilt; they must be removed from the garden and destroyed.

Bacterial wilt is primarily spread by two insects––the spotted cucumber beetle and the striped cucumber beetle. The spotted cucumber beetle is about 1/4-inch long, slightly round with eleven black spots on its wings. The body is yellow to greenish yellow. The striped cucumber beetle is 1/5-inch long, oval with three distinct parallel black stripes and a yellow body.

Overwintering adults emerge in the spring while some spotted cucumber beetles migrate north. They both lay small orange eggs at the base of plants from April thru June. The slender white larvae weaken plants by feeding on the roots and crowns. The larvae of spotted cucumber beetles are also called southern corn rootworms because they feed on corn roots.

The striped cucumber beetle can overwinter as an adult under debris in wooded areas and along fence rows next to cucurbit fields. There is still some question if the striped cucumber beetle can overwinter in Minnesota or migrate into the state each year. After they emerge, the adults feed on the blossoms of many alternative hosts such as hawthorn, dandelion and many other plant species. Once cucurbit plants emerge, the beetles are attracted to them. The striped cucumber beetle will not take flight until the mean daily temperatures reach 65 degrees. Feeding and mating begin shortly after.

After mating, females begin laying eggs in the soil at the base of the cucurbit plants. Eggs hatch in about a week and larvae feed on the roots and underground portions of stems of the plants. A second generation of adult striped cucumber beetles will emerge and begin to feed on foliage, flowers and fruits, if present. They hide in the soil around the plant under clogs of soil or in cracks in the soil during the heat of the day.

Adult feeding is a real concern when the leaves are in the first to third true-leaf stages. At this size the plants are small enough that a high population of striped beetle can either defoliate the plants completely or girdle the stems. Also, this is the time when bacterial wilt kicks in. Once flowering occurs the striped beetle will usually move off the foliage and begin feeding on blossoms and pollen. This is more noticeable on the larger flowering squash and pumpkins. Feeding on the flowers does not usually become a yield concern.

When you see a few beetles early in the season they may be controlled. They are much easier to pick off than the asparagus beetle as they are not as fast. If you must use a chemical, use malathion or carbaryl (sevin). There is a newer product on the market called Eight, but be sure that is effective on the cucumber beetle. Always check the pesticide label before spraying on vegetables. Don't do any spraying when the cucumbers are in the flower stage as you will destroy beneficial insects such as bees.

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Upcoming Classes

•July 14, 6:30-8 p.m.

Annuals for season-long bloom

Fairview Regional Medical Center, Wyoming

Cost: $4

Please call the office to register. 674-4417.For information on upcoming topics in the Summer 2005 Flowering Gardening Series and how to buy tickets, call or stop by the Chisago County Extension Office, 38780 8th Ave, North Branch, or visit our website to download a ticket order form at: www.extension.umn. edu/county/chisago.

July 26––FREE CLASS!

Dave Hanson––Trees, Trees, Trees

We receive more questions on trees than any other topic. Come learn about selection, planting and care, pruning, diseases and how to contact an arborist. Dave is a Research Specialist and Tree Care Advisor Coordinator, Urban and Community Forestry, University of MN, Department of Forest Resources. If he doesn’t have the answer to your question, he will know who does!

In Your Yard and Garden

It's time to mulch your garden. A 2-3-inch layer of organic material such as straw, compost, wood chips or grass clippings will help to retain soil moisture and also cut down on weeds. It also helps with plants like tomatoes to reduce fungal diseases on the leaves because it prevents the soil from splashing on the foliage. Some people will put cardboard or black and white newspaper under the mulch to increase the effectiveness of the barrier. Leave a 2-3" circle around the plant stem so it doesn't get too wet.

Finish pruning your spring flowering shrubs as they will soon begin to set their flower buds for next year. If you wait until later to prune them, you will be reducing the amount of flowers you will have next year. It's a good time to trim back and shape the spireas as they finish their bloom now. This will often result in repeat blooms at the end of the summer.

Ways to access information:

Master Gardeners will be offering free plant clinics every Monday night, from 4:30-8 p.m., at the Extension office in North Branch. Stop by 38780 Eighth Ave. (the Anderson Chiropractic Building) or call 651-674-4417 to speak with a Master Gardener. During the rest of the week, you can leave a message and a Master Gardener will return your call.

You can also click on 'Ask a Master Gardener' next to the cute little flower on the right hand side of the page. Here you can search 1000's of answers from Master Gardeners around the state. If you don't find your answer you can submit a question online or search for University publications.

Bell Museum of Natural History

For information about snakes, skunks, raccoons or other wildlife around your yard, call the wildlife information line at (612) 624-1374 or www.bellmuseum.org

To see the latest Yard and Garden newsletter, go to: http://www.exten sion.umn.edu/yardandgarden/YGLNews/YGLNews.html.

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