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Blog Post: http://www.ksuhortnewsletter.org
Video of the Week: Butterfly Gardens
https://kansashealthyyards.org/all-videos/video/butterfly-gardens
REMINDERS
Apply preemergent herbicide to lawn if you haven’t already
Turn compost pile
Prune spring-flowering shrubs such as forsythia and lilac after blooming if needed
Sidedress cabbage, broccoli and cauliflower 3 weeks after transplanting. See https://tinyurl.com/j2ggaa6 for sidedressing chart.
Sidedress onions 2 to 4 weeks after transplanting.
FRUIT
Pest Control on Fruit Trees
It can be a challenge to know how to spray fruit trees for pest control. Spray schedules will vary depending on whether the trees have fruit or not. Following are hints on what to spray this year for our most common fruit trees.
Peaches, nectarines and apricots: Often late frosts prevent fruit set on these fruit. Trees that are in full bloom, become much more sensitive to frost damage than those with buds still closed. Temperatures at 28 degrees and lower will harm buds that are in full bloom.
If there will not be any fruit, there isn’t any need for being on a spray schedule. If there is fruit, use a product that contains captan or myclobutanil (Immunox, Fungi-Max, Fertilome F-Stop Lawn and Garden Spray) from now until about two weeks before harvest. Spray about every 10 days.
If a specific problem develops such as borers, peach leaf curl or gummosis on peach, see our listing of common problems at our “Common Plant Problems in Kansas” website. Look under “Peach” for possible problems and what to do about them.
Cherries: We often have good fruit on cherries without spraying. However, a wet period as fruit ripens can lead to problems with brown rot. Myclobutanil (Immunox, Fertilome F-Stop Lawn and Garden Spray, Fungi-Max) or Captan will give good protection. Cherry fruit fly may attack the cherries with the maggot causing damage to the fruit. Malathion (check label), Bonide Fruit Tree & Plant Guard or Sevin can be used for control.
Pears: Pears are often able to escape damage without spraying. If trouble does arise, use the same recommendations given for apples.
Apples: Apples are the crop most in need of a spray schedule. Unless you have disease-resistant trees, cedar-apple rust is a perennial problem. The larvae of the codling moth is the insect most likely to damage fruit. Control can be a challenge due to changing labels and an extended spray season. See our article in our March 22, 2022 newsletter on “Apple Tee Sprays” for details.
We have three publications that give an overview of fruit pest control that are helpful.
Spray Schedules for Growing Apples at Home
Spray Schedules for Growing Stone Fruit at Home
Fruit Pesticides, Active Ingredients, and Labeled Fruits
Don’t overlook the “Fruit Pesticides…” pub as it lists trade names as well as other very important information. (Ward Upham)
Controlling Weeds in Strawberries
Although a popular fruit among home gardeners, strawberries present a major issue when it comes to weeds. The trailing growth habit of strawberry plants creates a groundcover which makes hoeing a problematic form of weed control. Hand pulling weeds is recommended for small plantings. For larger plantings, herbicides may be more appropriate.
Poast (sethoxydim) is a grass-killing herbicide that can be used once weedy grasses appear in the strawberry patch. This herbicide can be sprayed directly over strawberries without causing harm to the strawberry plants. Anytime chemicals are applied to a crop pay close attention to the directions for re-entry and in the case of edible crops, note the pre-harvest interval (PHI). Strawberries should not be harvested within seven days of application of Poast. Poast can be found in Fertilome Over the Top II and Hi-Yield Grass Killer. (Cynthia Domenghini)
Fruit Tree Sprays and Rain
A spreader-sticker is used to improve the distribution and retention of fungicides and insecticides on fruit and leaves. Many gardeners may not be familiar with these products but they can help our fungicides and insecticides work better. Look for a product that is called “Spreader-Sticker.” Big box stores rarely carry these products but garden centers or well-stocked hardware stores often do. These products should be used with fruit tree sprays as it allows the spray to coat leaves and fruit more thoroughly and to resist being washed off during rain events. However, even with a spreader-sticker, a rain can reduce the length of time the materials are effective. Less than one inch of rain since the last spray will not significantly affect residues. As a general rule, one to two inches of rain will reduce the residue by one half. Reduce the number of days until the next spray by one half. More than two inches of rain since the last spray will remove most of the spray residue. Re-spray as soon as possible. These recommendations apply for a soft, gentle rain. If you have a hard, driving rain, cut the above recommendations in half. (Ward Upham)
PESTS
Ash/Lilac Borer
Note: Ash/Lilac Borer is a different insect than Emerald Ash Borer. Ash/Lilac Borer has been around for many years while Emerald Ash Borer has a more limited range in eastern Kansas. As far as I know, Emerald Ash Borer has not been confirmed west of the Topeka area.
If you have had problems with canes or stems of lilac and privet suddenly wilting, or ash trees that show borer holes in the trunk and larger branches, the ash/lilac borer may be to blame. This insect causes the base of infested lilac stems to swell and the bark to separate from the wood. A fine sawdust-like material is present around holes in the canes. Ash and mountain ash also are affected. The borer attacks the trunk, which may cause bark to swell and crack if there are repeated infestations.
Ash/lilac borers overwinter as larvae in infested trees and shrubs. Moths generally begin to emerge in mid to late April. Emergence peaks in May, dwindles by mid to late June and ends by the first week of July. However, this varies by year. The moth has clear wings and resembles a wasp. There is one generation per year.
Public and commercially managed properties often use pheromone traps to determine the presence of adults. Spray treatments are started seven to 10 days after capture of the first moths.
Sprays also can be timed using phenology, the practice of timing one event by another. The first spray for ash/lilac borer should be applied when the Vanhoutte spirea is in full to late bloom. This is often about the third week in April but can be as early as late March and as late as mid-May. Apply a second spray four weeks after the first. The Missouri Botanical Garden has several images of Vanhoutte spirea.
Thoroughly treat the trunk and larger limbs of ash or the lower portion of the stems of lilac or privet. Heavily infested ash should be cut and burned during the fall and winter. Infested stems of lilac or privet should be removed as well.
Products with bifenthrin or permethrin (Hi-Yield Garden, Pet, and Livestock Insect Control and 38 Plus Turf, Termite and Ornamental Insect Control) are labeled for control. Though there are a number of homeowner products that contain one or the other of these two active ingredients, the permethrin products listed above are the only ones I’ve found that specifically lists the ash/lilac borer on the label with directions for control. (Ward Upham)
Mole Control
Though moles spend most of their time underground, the damage they cause above ground is all too visible. Meandering paths of upheaved soil are evidence of the small mammals foraging for food. If soil is dry, moles form mounds of soil but do not make the meandering paths. Some tunnels may be abandoned soon after being built while others are travel lanes and used for a longer period of time. Even though moles do not feed on plant matter, they can still cause damage by disturbing roots and uprooting small plants.
Numerous home remedies have been concocted to control moles including chewing gum, noisemakers, broken glass, bleaches, windmills, and human hair. None have been found to provide consistent and reliable control. Poison baits also fail to work because moles feed on earthworms and grubs, not vegetable matter. Even grub control products are ineffective as they do not control earthworms, and earthworms are the primary food source for moles.
The best control method is the use of traps. There are three types of traps (harpoon, choker, and scissor-jawed) and each can be effective but may take some time to master. Try the following suggestions.
Moles use some tunnels more than others. Use a broomstick or something similar to poke holes in a number of runs. Check a day later to see which runs have been “repaired.’ These are the active runs and should be used for trap placement.
Place a trap in an active run by excavating soil, placing the trap and then replacing loose soil. Secure the trap so that the recoil will not lift the trap out of the ground. Make sure the triggering mechanism is in the center of the run.
Finally, push down two more holes, one on each side of the trap. Moles should be caught when they try to repair the tunnel. Move traps if no moles are caught within three days.
Our KSU Extension Wildlife Management website has information on mole control including videos and printed material. (Ward Upham)
TURFGRASS
Controlling Wild Violets in Lawns
One of the most difficult weeds to control in lawns is the wild violet. Even combination products that contain 2,4-D, MCPP and Dicamba such as Trimec, Weed-Out and most formulations of Weed-B-Gon do not do a good job. Products with triclopyr give much better control though more than one treatment will likely be needed. The products that contain triclopyr on the homeowner side are Turflon Ester, Triclopyr Ester and Weed-B-Gon Chickweed, Clover & Oxalis. (Note: There are several formulations of Weed-B-Gon but only Weed-B-Gon Chickweed, Clover & Oxalis contains triclopyr.)
The products listed above are labeled for tall fescue and Kentucky bluegrass. Do not use products containing triclopyr on bermudagrass as severe injury will occur. Weed-B-Gon Chickweed Clover & Oxalis is labeled for buffalograss and zoysia (Turflon Ester and Triclopyr Ester are not) but lawns will likely show some temporary browning after application.
Spray only on calm days and when temperatures are below 90 degrees to avoid damage to nearby plants. (Ward Upham)
MISCELLANEOUS
Butterfly Gardening
Butterfly gardening continues to grow in popularity. With the lengthy list of pollinator plants, knowing what species butterflies prefer can facilitate gardeners with their selections. Some annuals known to attract butterflies include: ageratum, cosmos, French marigold, petunia, verbena and zinnia. Group similar species of annuals together to create a planting more likely to attract butterflies. Including a mix of annuals with varying bloom times can lengthen the butterfly season.
Early blooming perennials/shrubs that attract butterflies include: allium, chives, forget-me-not and lilac. Bee balm, butterfly bush, black-eyed Susan, buttonbush, butterfly weed, daisy, daylily, gaillardia, lavender, lily, mint, phlox, privet, sunflower and veronica are all good options for a mid-season bloom. Aster, glossy abelia and sedum are late bloomers that attract butterflies.
Other features you can incorporate in the garden to appeal to butterflies include areas of full sun. Butterflies are cold-blooded so they seek sunshine for warmth. Shade is also necessary so they can escape from intense sun.
Water is important for butterflies. This can be provided with a simple birdbath or even a water-filled saucer placed on the ground.
Visit Monarch Watch (www.monarchwatch.org) to find resources for attracting monarch butterflies to your landscape. This organization provides educational material about all things Monarch butterflies, as well as supplies to become an official Monarch waystation. This is a great resource for schools, environmentally-focused organizations and even home gardeners.
Here is a fact sheet about butterflies from our Johnson County Master Gardeners. (Cynthia Domenghini)
Contributors:
Cynthia Domenghini,. Instructor
Ward Upham, Extension Associate
Division of Horticulture
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Cooperating, Ernie Minton, Dean.
