Vegetable Crop Rotation

Transcription

1 Hello Jefferson County Master Gardeners! It is May. It really looks and feels like winter is over. This has been a very long winter and I hope God blesses us with a much anticipated spring and then summer. Vegetable Crop Rotation By Sarah Denkler, MU Horticulture Specialist, Butler County I heard about crop rotation. I don t have crops. What is it and why would I care? Crop rotation is an idea used by growers of agriculture crops as well as vegetable growers. Homeowners, although they do not grow crops should also practice crop rotation, or really vegetable rotation. Rotation is related to Integrated Pest Management practices. There is no one way or quick fix to solve insect and disease issues when growing plants. Integrated Pest Management is the practice of using multiple tools to manage insect populations or disease pressure. The idea is not to wipe out a population but to observe how multiple strategies can keep a population at a minimum level to reduce pest problems on desired plants. An example might be introducing predatory insects, growing flowers and providing the ideal water and nutrient levels to grow a tomato in preparation of a population of aphids. As the aphid population levels increase, the (continued on page 2) I know this won t reach many of you before the annual Kress Farm plant sale on Saturday, May 5, 2018 so I hope that many of you have this day marked on your calendars and will be there. The Kress Farm plant sale is a good time to see old friends and perhaps to make new friends. We gardeners need gardening friends to keeps us fresh and motivated. I m developing a butterfly garden in a part of our yard. I ll include a photo when it is complete. One of the plants we placed in the garden is a flowering ninebark which according to the growers tag is deer resistant. Unfortunately, the deer around my garden (continued on page 2) Inside this issue Understanding Insecticide Modes of Action... 3 Calendar of Events... 5 What is it?... 5 Summer Bulbs to Try... 5 Coordinator Update... 6 Missouri Botanical Highlight... 6 May Gardening Calendar

2 Jefferson County Master Gardener Vegetable Crop Rotation (continued from front page) regular watering will maintain turgor in the plant even though the aphids are sucking sap from the tomato. The early spring flowers will attract ladybugs that will begin to feed on the aphids and the nutrients in soil will give the plants enough energy to maintain their health until the ladybugs reduce the aphid population. Crop (vegetable) rotation is a tool used in Integrated Pest Management that is most commonly used when a disease organism, usually a fungus, has infected plants in a particular soil. Some fungal organisms do not die over the winter and will maintain a population in soil for several years. By rotating plants out of this soil to clean soil, the organisms lose their food source and will eventually die out. Rotation is practiced on a three year cycle in most cases and in some on a five year cycle. It depends on the organism. Brassicas such as mustard and cabbage can be planted as cover crops to help reduce the disease organism population further. It is important to note that a plant from the same family should be part of this rotation. In other words, if tomato plants became infected and must be rotated out then eggplant, pepper and potato will also be rotated out of the soil for three years as they are all in the Solanaceae family. This family also includes petunia, capsicum, paprika and tobacco. From the President... (continued from front page) can t read. I started some marigold seeds I collected and purchased in the house with good results. However, I started them too early and many of them have become composting material. My son and I did manage to salvage four of the seedlings and transplanted them into pots and placed them outside under the eve of the house so we will see how those turn out. Don t forget to record your volunteer hours. The 2018 Level 1 Master Gardener class is finishing up on Monday, May, 7, Congratulations to the new MG s. During one of the classes as I was preparing to display and sell T-shirts I discover some errors on some of the shirts. Some of the shirts did not have the Extension logo on the back of the shirt. And some of the Tshirts had the word extension misspelled on the back of the shirt. Kathy in the Extension office researched to determine when the shirts were purchased and determined that some of the shirts were purchased two (2) years ago and some that we were unable to determine when they were purchased. We bought new Tshirts from a local vendor. We verified the copy for the shirts and inspected the shirts upon delivery. The new shirts are A-OK and will go on sale today. The price of the new shirts is $15.00 each. Any one with a T-shirt with the above described errors will be able to get a replacement shirt at no charge. On one condition. I ask that you bring the shirt to be replaced with you for the exchange. That way we can get the erroneous shirts out of circulation and the public eye. Enjoy getting dirty in the garden. And watch out for hazards. Tom 2

3 Jefferson County Master Gardener Understanding Insecticide Modes of Action Many insecticides are available to home gardeners wanting to control insects, from various organic sprays, to the many synthetic sprays out there on the market. When choosing an insecticide, first identify the insect you want to control and how it is best controlled. Can you control it by hand-picking? Can it be controlled by a contact poison, or is it best controlled using an oil and suffocating it? Many times home gardeners become frustrated because the product they used did not work. The reason it may not have worked, is that it was not the right mode of action for the insect they wanted to control. For example, the insecticide Sevin is not the best product to use on scale insects. Sevin, containing the active ingredient carbaryl, is a poison. The best product to use on scale insects, is an oil which kills by suffocation. Always read the label to see if the pest you want to control is listed. If it is not, then do not use it. Always read and follow label directions on all pesticides. Poisons: The most common group of insecticides is the nerve poisons. These insecticides disrupt an insect s nervous system. They are absorbed through the insect s exoskeleton and are considered contact insecticides. Common contact insecticides include carbaryl, diazinon, chlorpyrofos, pyrethrins,and permethrin. Other poisons have systemic activity, meaning that when they are applied to the plant s leaves or roots, the plant absorbs the insecticide into its tissue, and the insect is poisoned when it feeds from the plant. Examples of systemic insecticides are imidacloprid, dimethoate and disulfoton. Some products, such as acephate and dimethoate, are both contact and systemic insecticides. Suffocating/drying pesticides: insects are suffocated by oils and dried out by insecticidal soaps. Two kinds of oils are typically available for treating insects: dormant oils & summer horticultural oils. Both types affect immature and adult insects. Dormantoils may be applied only to deciduous plants (trees and shrubs that lose their leaves in the fall) when the plants are dormant. Be careful with evergreen plants. Oils may injure or discolor some species. Summer oils are lighter than dormant oils and may be applied during the summer on deciduous plants and throughout the year on many evergreen trees and shrubs. Some horticultural oils may also be mixed with other insecticides to control insects more effectively. Insecticidal soaps disrupt the waxy cuticle or skin of the insect, which eventually causes the insect to dry out and die. IGRs: Insect growth regulators interfere with an immature scale insect s ability to molt (shed its outer skin to allow for growth); in some cases, IGRs suppress egg development. Although these insecticides often act more slowly than contact insecticides, they can effectively control many species of insects. Examples of IGRs include azadirachtin and pyriproxyfen. Modes of action for these insecticides can divided into three general groups based on how they control insects: poisons which the insect has to ingest; suffocation, which causes them to dry out and die; and insect growth regulators or IGRs, which disrupt molting. (continued on next page) 3

4 Jefferson County Master Gardener Understanding Insecticide Modes of Action (continued from page 3) Most insecticides are formulated as: Wettable or soluble powders (WP, S), which are mixed with water and sprayed onto an infested plant; Emulsifiable concentrates (EC), which also are mixed with water and sprayed onto infested plants; Granulars (G), which generally are applied around the base of a plant and watered into the soil; Dusts, which are applied directly onto infested plants; Aerosols, which also are applied directly onto plants. Beware of phytotoxicity, which is the damage that pesticides cause to plants. Many plants are sensitive to various pesticides. If you re in doubt, treat a small part of the plant, then check a day or two later to see if the plant tissue is yellowed or burned. Many pesticide labels list the plants that are susceptible to phytotoxicity if those products are used on them. An alternative choice to using insecticides is companion planting. Companion plants like basil planted with tomatoes help keep away hornworms; marigolds and nasturtiums planted among cucurbit crops help deter cucumber beetles and squash bugs; and chives or garlic planted near lettuce helps keep away aphids. Plant companion plants the same time you plant your vegetables. Not only will the companion plants provide insect protection, but they are also edible. Use basil to make a tasty tomato-basil salad or pesto. Chives and garlic are used in a variety of dishes, and flowers of nasturtium are edible. The Tagetes hybrids or Calendula members are generally the cultivars used for growing edible marigold flowers. Calendula is not technically a marigold, as it is not botanically related; however, it is often called pot marigold and confused with the Tagetes genus of marigolds. Source for modes of action: Texas Agrictural Extension Service Did you know... during the month of May Birds eat many insect pests. Attract them to your garden by providing good nesting habitats. Herbs planted in average soils need no extra fertilizer. Too much may reduce flavor and pungency at harvest. Take houseplants outdoors when nights will remain above 50 degrees. Most prefer only direct morning sun. Watch for fireflies on warm nights. Both adults and larvae are important predators. Collecting may reduce this benefit. Sink houseplants up to their rims in soil or mulch to conserve moisture. Fertilize regularly. 4

5 Jefferson County Master Gardener Calendar of Events May 5 Kress Farm Plant Sale, Hillsboro, MO 15 Bimonthly Meeting, Viking Room on Jefferson College Campus, Hillsboro, MO 17 - Gardening under a Black Walnut Grove, Shaw Nature Preserve, Grey Summit, MO. Call (Level II class) Garden Walk and Plant Sale, Ste. Genevieve June Welcome Center; for more information, call Summer Horticulture Tour to Daylilies of the Valley from 10 a.m. to noon, Ironton. Call The Art of Combining Native Perennials, Shaw Nature Preserve, Grey Summit, MO. Call (Level II class) 28 - Twilight Tour: Urban Buds City Grown Flowers, St. Louis, MO. Call $ Tomato School at the Cape Girardeau County Extension Center in Jackson, MO. Call Find the answer somewhere in this newsletter :) July 10 Bimonthly Meeting, Viking Room on Jefferson College Campus, Hillsboro, MO 12 - Flower Arranging with Native Plants, Shaw Nature August Preserve, Grey Summit, MO. Call (Level II class) 9 - Pondscaping with Native Plants, Shaw Nature Preserve, Grey Summit, MO. Call (Level II class) September 28-30: State Master Gardener Conference, Chateau on the Lake, Branson, MO. Register now at Summer Bulbs To Try This Year Summer bulbs add beauty and interest to landscapes. Summer bulbs like warm temperatures and humid conditions so they do well in Missouri. They should be planted after the danger of frost is past and should be placed in well drained areas. Many need to be dug after a killing frost in fall but there are a few that will overwinter in the southern Missouri counties. Commonly planted bulbs to try include: Asiatic Lily Caladiums Calla Lily Cannas Dahlias Elephant Ears Freesia Gladiolus Oriental Lilies Surprise Lilies Tuberous Begonias 5

6 Jefferson County Master Gardener Master Gardener Coordinator Update Missouri Botanical Highlights Hello Master Gardeners. I think spring has finally arrived for good. What a relief after what seemed like a very long winter season. I ve been getting calls asking why their vegetables gardens aren t growing so well. Last year the plants were so much bigger. I ve been telling them we are 2-3 weeks behind due to the cool and cloudy spring we ve been having. Starting in mid-april, all horticulture specialists across the state meet via the computer to discuss issues we are seeing around the state as well as hearing updates from state specialists on campus. Here are a few things I d like to share from this past week s update. 1. Pat Guinan, the weather man as we all call him, the State Climatologist, informed us that even though we re getting a bit of rain here and there, that we are still behind in total rainfall for the year. So keep an eye to sky on how much rain you get and an eye on your plants. We may end up having to do extra watering this year on our gardens. May 19, :00 am 5:00 pm New cultivars and old favorites are shown and sold by the area s top growers, who are on hand to give plant care advice and share information about their organization. Included with Garden admission For more information on events and things to do, check out the Missouri Botanical website I M A BORAGE! 2. Homeowners with warm season lawns, particularly zoysia, are seeing issues from a hard fungus and bacteria issues last year with spots of die out now appearing. Advice is to fertilize as soon as the grass begins to turn green to encourage growth and spread of the zoysia. A few other updates: 3. The Volunteer Sites Location Committee will be presenting at the May Bi-montly Meeting on their work. They have been working hard and I would like to acknowledge them and their work. Did you Know I was Edible? 4. New T-shirts have arrived. They will be for sale at the May Bimonthly Meeting. Hope to see you out and about gardening! 6

7 Jefferson County Master Gardener May Gardening Calendar ORNAMENTALS Week 1: Continue monitoring pines, especially Scotch and mugo, for sawfly activity on new shoots. Week 1: Begin planting gladiolus bulbs as the ground warms. Continue at 2-week intervals. Week 1: Plant hardy water lilies in tubs or garden pools. Weeks 1-2: Don't remove spring bulb foliage prematurely or next year's flower production will decline. Weeks 1-2: Canker worms (inch worms) rarely cause permanent damage. Use Bacillus thuringiensis (B.t.) if control is necessary. Week 2: Begin planting warm-season annuals. Weeks 1-4: Apples, crabapples and hawthorns susceptible to rust disease should have protective fungicidal spray beginning when trees bloom. Weeks 1-4: Pinch azaleas and rhododendron blossoms as they fade. Double flowered azaleas need no pinching. Weeks 1-4: If spring rains have been sparse, begin irrigating, especially plants growing in full sun. Weeks 1-4: Fertilize azaleas after bloom. Use a formulation which has an acid reaction. Weeks 2-4: Scale crawlers are active now. Infested pines and euonymus should be treated at this time. Weeks 2-3: Plant summer bulbs such as caladiums, dahlias, cannas and elephant ears. Weeks 3-4: Begin fertilizing annuals. Continue at regular intervals. Weeks 3-4: Trees with history of borer problems should receive their first spray. Repeat twice at 3-week intervals. Weeks 3-4: Bulbs can be moved or divided as the foliage dies. Week 4: Pinch back mums to promote bushy growth. LAWNS Weeks 1-4: Keep bluegrass cut at 1.5 to 2.5 inch height. Mow tall fescue at 2 to 3.5 inch height. Weeks 2-4: Mow zoysia lawns at 1.5 inch height. Remove no more than one-half inch at each mowing. Weeks 2-4: Apply post-emergence broadleaf weed controls now if needed. Weeks 3-4: Zoysia lawns may be fertilized now. Apply no more than 1 pound of actual nitrogen per 1000 square ft. Week 4: Watch for sod webworms emerging now. VEGETABLES Weeks 1-4: Place cutworm collars around young transplants. Collars are easily made from cardboard strips. Weeks 1-4: Growing lettuce under screening materials will slow bolting and extend harvests into hot weather. Weeks 1-4: Slugs will hide beneath a board placed over damp ground. Check each morning and destroy slugs on the underside. Weeks 1-2: Plant dill to use when making pickles. Week 1: Keep asparagus harvested for continued spear production. Control asparagus beetles as needed. Week 1: Begin planting sweet corn as soon as white oak leaves are as big as squirrel ears. Week 1: Isolate sweet, super sweet and popcorn varieties of corn to prevent crossing. Week 1: Thin plantings of carrots and beets to avoid overcrowding. Week 1: Control caterpillars on broccoli and cabbage plants by handpicking or use biological sprays such as B.t. Week 1: Set out tomato plants as soils warm. Place support stakes alongside at planting time. Weeks 2-3: Place a stake by seeds of squash and cucumbers when planting in hills to locate the root zone watering site after the vines have run. Weeks 2-3: Remove rhubarb seed stalks as they appear. Week 2: Watch for striped and spotted cucumber beetles now. Both may spread wilt and mosaic diseases to squash and cucumber plants. Weeks 3-4: Set out peppers and eggplants after soils have warmed. Plant sweet potatoes now. Week 4: Make new sowings of warm-season vegetables after harvesting early crops. FRUITS Weeks 1-4: Mulch blueberries with pine needles or sawdust. Week 1: Don't spray any fruits while in bloom. Refer to local Extension publications for fruit spray schedule. Week 4: Prune unwanted shoots as they appear on fruit trees. -Missouri Botanical Garden- 7