If you come to our garden you may see white powder around the base of our squash, cucumber and zucchini plants.... its diatomaceous earth (DE). A study from the Southwest Entomology Journal showed that DE is almost as effective as toxic chemicals (such as Carbaryl) in reducing Squash Bug damage. It is not harmful to people, unless you get it in your eyes, or you breath it in. It can kill bees and other insect pollinators though, so we are following the Xerces Society recommendations (see page 3 of the link). Most of our plants are not yet blooming so there are no flowers to attract the pollinators. But we are putting the powder only around the base of the vines, not on the leaves, except directly on the egg masses, before crushing them.
I was weeding up at Education Gardens yesterday and discovered egg masses on our squash and pumpkin plants from Squash Bugs. I also found some Squash Vine Borers in amongst the grass around one of the winter squash plants. These are both pests of cucurbits, which are plants in the cucumber, squash and melon families. Thanks to the great talk Master Gardner Cindy Welke gave at Education Gardens last Saturday (see blog below) I was able to identify these bugs. Master Gardener Tom Kujawa, who has gardened for several years at Education Gardens has advised in the past that Diatomaceous Earth can be a non-toxic solution for some pests. Diatomaceous earth is the finely ground shells of fossilized hard-shelled algae, which is has very sharp edges (see magnification below). How does it work? This is what the National Pesticide Information Center web site says 'Diatomaceous earth causes insects to dry out and die by absorbing the oils and fats from the cuticle of the insect's exoskeleton. Its sharp edges are abrasive, speeding up the process. It remains effective as long as it is kept dry and undisturbed.' You can read more about it at their site. If you come to our garden you may see white powder around the base of our squash, cucumber and zucchini plants.... its diatomaceous earth (DE). A study from the Southwest Entomology Journal showed that DE is almost as effective as toxic chemicals (such as Carbaryl) in reducing Squash Bug damage. It is not harmful to people, unless you get it in your eyes, or you breath it in. It can kill bees and other insect pollinators though, so we are following the Xerces Society recommendations (see page 3 of the link). Most of our plants are not yet blooming so there are no flowers to attract the pollinators. But we are putting the powder only around the base of the vines, not on the leaves, except directly on the egg masses, before crushing them. Submitted by Chris Meyer, Winona County Extension Master Gardener
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Cindy Welke, University of Minnesota Extension Master Gardener, showed her passion and knowledge of good bugs and destructive bugs at her Bug Workshop this morning. She began with some life experiences with bugs and how she got her nickname of “Bug Lady”.
Two Quotes from Sun Tzu (c. 6th century BCE), a Chinese general, military strategist, and author of The Art of War, were used to give structure to her presentation. The first quote used says, “Know your enemy and know yourself and you can fight a hundred battles without disaster.” The quote’s connection with todays workshop was that by learning as much as you can about bugs you will get clues as to how to deal with the bad bugs and encourage the good bugs. Tzu’s second used quote states, “Strategy without tactics is the slowest route to victory. Tactics without strategy is the noise before defeat.” A gardener cannot effectively deal with garden bugs by simply reaching for an insecticide. Some actions against bad bugs can have a bad affect on the lives of good bugs. Wisconsin has 7000 identified insects but only 100 of them are harmful to garden plants. Here, Cindy gave a quick overview of Integrated Pest Management philosophy and stressed that we try to select a bug management program that is least harmful to the environment. Then the heart of the workshop began with identifying bugs in adult and immature stages using guides Cindy found in her research. (These guides and information from from the Purdue University Extension website: http://www. extension.entm.purdue.edu/publications/E-65.pdf , became a booklet that we took home and could use as a starting point for identifying bugs in our own gardens) The structure of an adult bug includes a head, thorax and abdomen. Each category of bugs are similar because of these three parts and are the clues for identification. Another identifier would be a bug’s mouth parts. Knowing that a bug has a piercing and sucking, chewing or siphoning mouthpart can help in picking a method of control. Another guide showed the immature stage of a bug and was identified as the stage that is the easiest to control. Here the bug takes the form of a miniature adult (nymph), caterpillar or grub. Attempting to identify a group of actual bugs that Cindy brought helped to practice looking at and identifying bugs and classifying them as good bugs or bad bugs. Methods of control were next classified and discussed. These methods include: mechanical, cultural and knowing yourself: Mechanical control examples were simple sanitation, tilling, hand picking, using barriers and staking. Information from Iowa State University Extension about the identification and use of botanical insecticides was given. If a pesticide is to be used, do spot treatments rather than general broadcasting of the control. Be aware that insecticide labels must list the pest, the plant and when to harvest. Also, be aware that the label is the “law” with regard to use of the pesticide. Suggestions for Cultural control of bugs were: don’t stress plants, harden off well, use barriers, rotate crops, choose best resistant variety of plant, take a 5 minute walk each day and observe, use natural enemies like the Lacewing. Knowing yourself is a method of control as it includes identifying your threshold of tolerance to damage. Some damage is strictly cosmetic or may last only a short time. Also, by keeping record of your garden insects and your method of control or encouragement will help you make better choices in future gardens. An excellent book resource for beginning “bugologists” was identified as “Good Bug/Bad Bug: All you need to know about the insects in your garden” by Jessica Wallister. The more experienced person would really enjoy “The Ultimate Guide to Backyard Bugs: Garden Insects of North America by Whitney Cranshaw. The morning was completed with a tour of the Education Gardens and Project FINE’s Colorful Growers garden and a chance to put into practice some of the information from the workshop. Cindy was also able to add to her collection of bugs and offered to return for another presentation. Submitted by Tom Kujawa, University of MN Extension Master Gardener Our summer gardening programs start this week with the Family Gardening program. We have some beautiful crops growing at Education Garden thanks to the Winona Middle School 7th grade and their teachers. Learn more about us in this article from the Winona Daily News.
Submitted by Chris Meyer, Winona County Extension Master Gardener Joyce Altobelli, University of Minnesota Master Gardener for Winona County, presented the rather complex topic of Integrated Pest Management (IPM) to a gathering of 11 experienced and beginning gardeners. Her style of presentation is one of keeping her students thinking through questions and applying some of the concepts to actual gardening situations and the experiences of the audience. The topic is complex because of the factors one needs to consider when developing a plan for dealing with destructive bugs and/or pesky weeds. Joyce’s outline that follows will introduce you to some terms and ideas of IPM that she presented:
Integrated Pest Management
Integrated Pest Management Tools and Resources
Submitted by Tom Kujawa, University of Minnesota Master Gardener The Education Gardens will get a rototiller thanks to the Winona Community Foundation. Read about our grant in the Winona Daily News.Healthy Soil and Soil Testing Workshop |