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. A couple of products that contain triclopyr on the homeowner side are Turflon 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.)
Both 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 is 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)
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: Check to make sure the fruit buds were not winter killed. Just touching dead buds will cause them to fall off. These fruits are also very susceptible to late frosts as they bloom early. 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, 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 spring can lead to problems with brown rot. Myclobutanil (Immunox, Fertilome F-Stop Lawn and Garden Spray) 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 24, 2020 newsletter on “Apple Tree Sprays” for details.
We have three new 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)
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)
Fruit Bud Damage from Cold Temperatures
Fruit growers often wonder at what temperature fruit buds are killed. The following will give you some guidelines but remember that the actual damage is going to be influenced by the weather before the temperature drops. An extended warm spell before the cold snap may result in more damage due to a loss in cold hardiness.
Apple
Stage 10% Kill (°F) 90% Kill (°F)
Silver tip 15 2
Green tip 18 10
Half-inch green 23 15
Tight cluster 27 21
Pink 28 25
Bloom 28 15
Petal fall 28 25
Fruit set 28 25
Pear
Stage 10% Kill (°F) 90% Kill (°F)
Swollen bud 15 1
Bud burst 20 7
Green cluster 26 15
White bud 26 22
Bloom 28 23
Petal fall 28 24
Fruit set 28 24
Peach
Stage 10% Kill (°F) 90% Kill (°F)
Swollen bud 18 2
Half-inch green 23 5
Pink 25 18
Bloom 27 24
Petal fall 28 25
Fruit set 28 25
Tart Cherry
Stage 10% Kill (°F) 90% Kill (°F)
Bud burst 17 5
Green tip 25 14
Tight cluster 26 17
Swollen bud 27 24
Bloom 28 25
Petal fall 28 25
Fruit set 28 25
Plum and Prune
Stage 10% Kill (°F) 90% Kill (°F)
Swollen bud 14 1
Bud burst 18 3
Green cluster 26 16
White bud 26 21
Bloom 27 23
Petal fall 28 23
Fruit set 28 25
Apricot
Stage 10% Kill (°F) 90% Kill (°F)
First white 24 14
First bloom 25 19
Full bloom 27 22
In the shuck 27 24
Green fruit 28 25
To determine whether a fruit bud is alive or dead, use a sharp knife or a single edge razor blade and cut buds in half. Remove buds from the tree and make the cut starting at the base and cutting upward. If the fruit pistil (see image) in the center is greenish white to cream color, no damage has been done. However, if the fruit pistil is dark brown or black, it has been killed. Cut a number of buds to find a percentage killed.
Some loss of buds is actually beneficial for peaches and apples. These trees often produce far too much fruit and require thinning for top quality. As a rule, we want an apple or peach an average of every six to eight inches on a branch. We can often achieve this with only 10% of the original buds developing fruit. (Ward Upham)
Controlling Weeds in Strawberries
Strawberries are one of the most popular fruits, but gardeners often have problems with weed control. Strawberries form a mat of plants, which makes hoeing difficult. Gardeners must pull weeds by hand or use herbicides. In small plantings, hand weeding is usually sufficient as weeds become less of a problem when the plants canopy over to block sunlight to the soil. In larger plantings, herbicides may prove helpful.
Although there are no weed preventers available for homeowners to use on strawberries, Poast (sethoxydim), a grass-killing herbicide, can be used after weedy grasses have emerged. It can be sprayed directly over strawberries without harm but should not be applied within 7 days of harvest. You can find Poast in Fertilome Over the Top II, Hi-Yield Grass Killer and Monterey Grass Getter. (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 been confirmed in only Atchison, Doniphan, Douglas, Jackson, Jefferson, Johnson, Leavenworth, Miami, Shawnee & Wyandotte counties in Kansas.
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)
Nantucket Pine Tip Moth
The Nantucket pine tip moth, Rhyacionia frustrana, is an insect pest of Austrian and Scots pines in Christmas tree plantations, hedgerows, and landscapes. Nantucket pine tip moth is native to the eastern and southern portions of the USA. Adult moths are 1/4 inches (6.3 mm) long with the head and body covered with gray scales. The forewings are covered with brick-red to copper-colored patches that are separated by irregular bands of gray and white scales. Adult moths are active from early evening until dusk and can be found in the canopy of pine trees during the day. Adult females lay white to opaque eggs on shoots, needles, or buds (terminal growth) in spring. Young larvae (caterpillars) that hatch from eggs are 1/16 inches (1.6 mm) long, and cream-colored with a black head. Older or mature larvae are yellow to orange, and 3/8 inches (9.5 mm) in length.
First instar larvae create mines in needles resulting in necrotic spotting. Later, the larvae exit the needles and then tunnel into and feed within the inner tissues of shoots, and buds, resulting in branch tips turning brown and dying. Damage associated with Nantucket pine tip moth larvae results in deformed growth (stem crooking) or a reduction in growth (bushy or stunted growth), which reduces the aesthetic quality and degrades the value of Christmas trees and pine trees in landscapes. Trees can be killed when exposed to repeated Nantucket pine tip moth larval infestations. An indication of a Nantucket pine tip moth infestation is the presence of silken tent-like webbing on shoot tips covered with masses of accumulated plant resin. In addition, fecal deposits may be present in the webbing on the outside of infested shoots. Larvae feed for up to four weeks before pupating. Nantucket pine tip moths overwinter as pupae that are dark-brown and 1/4 to 1/2 inches (6.3 to 12.7 mm) long. The pupae are located in cavities created by larvae within damaged shoots or terminals. Adults emerge (eclose) in about 10 days. There are three generations per year in Kansas.
Management of Nantucket pine tip moth involves implementing proper watering, fertilization, and mulching practices to keep pine trees healthy, which encourages the development of new growth. For minor infestations, you can hand prune infested shoots if branches are reachable. In addition, Christmas trees can be sheared to remove infested shoots.
It is important to monitor adult populations in April using pheromone traps containing a lure that attracts males. Pheromone traps should be placed among susceptible pine trees and inspected weekly. Seven to 10 days after males are captured in the pheromone traps, insecticide applications should be initiated. The benefit of monitoring is that it helps time applications of insecticides. Applications of contact pyrethroid-based insecticides (e.g. permethrin or lambda-cyhalothrin) or spinosad must be made weekly for each generation until adult males are not captured in pheromone traps. Insecticide sprays should target young larvae that feed on the outside of shoots. This increases exposure to spray residues before the larvae enter shoots. Consequently, thorough coverage of all plant parts is important to ensure effectiveness of applications. Once larvae are located inside plant tissues, insecticide applications will not be effective because larvae will not be exposed to insecticide residues.
Note: Peak moth emergence was noted in the Wichita area on April 8.
MISCELLANEOUS
Butterfly Gardening
Butterfly gardening is becoming more popular with Kansans. Providing for the basic needs of butterflies, such as food, shelter and liquids, will encourage butterflies to visit this summer. There are a number of plants that attract butterflies.
However, different species of butterflies prefer different plants. Using a variety of plant material that vary in blooming times of day and year helps attract a diverse group of visitors. Plant groups of the same plant together; a single plant is difficult for a butterfly to detect. If trying to attract a certain species of butterfly, learn which plant(s) that butterfly prefers, and then emphasize that plant in your planting. Annuals that attract butterflies include ageratum, cosmos, French marigold, petunia, verbena and zinnia.
Perennials and shrubs can be split into those that bloom early, mid-season and late. Good choices for those that bloom early are 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 fitting picks for mid-season bloom. Late bloomers include aster, glossy abelia and sedum.
There are other things you can do to encourage butterflies. Butterflies are cold-blooded and like open areas where they can sun themselves on cool days and shade to cool off when the sun is too intense.
Butterflies also need water. A simple way to make a butterfly pool is to take a bucket, fill it with gravel, and bury it to the rim. Now add water, sugar water or sweet drinks so that the butterflies can land on the gravel but still reach the liquid.
Monarch Watch is an organization that focuses on Monarch butterflies and supplies free milkweed plants for relatively large restoration projects as well schools and educational non-profits. The site also provides extensive information on the Monarch butterfly and on what you can do to increase the population.
Our Johnson County Master Gardeners have put together a fact sheet on creating a butterfly habitat. (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)
Contributors: Raymond Cloyd, Extension Entomologist; Ward Upham, Extension Associate
Division of Horticulture
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