1712 Claflin, 2021 Throckmorton Plant Science Center
Manhattan, KS 66506 (785) 532-6173
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VIDEO OF THE WEEK:
Drought Tolerant Plants for a Challenging Kansas Landscape
(Archived K-State Garden Hour)
You might not be thinking about drought right now with the spring weather, but it inevitably affects our landscapes at some point during the summer.
April GARDEN CALENDAR
Find out what to plant in the garden this spring.
VEGETABLES
Planting Warm Season Veggies
Most of our warm-season vegetables can be planted in early May, however, winter squash and pumpkins should be delayed until mid to late June. The first generation of squash bugs is active in July. Delaying the planting date for squash will result in younger plants that can escape this round of squash bug damage. Plants will need protection from the second generation of squash bugs which is present in August.
To read more about squash bugs visit our KSRE publication: Squash Bugs
Protecting New Vegetable Transplants from the Wind
Wind is an important environmental feature for the plant world. Many plants rely on the wind to disperse seeds and transfer pollen from one plant to another. Young plants strengthen their stems as a result of nudging from the wind. As you move seedlings into the garden remember to harden them off by exposing them to the elements gradually. Without preparing the plants for the wind through increased exposure they are more susceptible to breaking under this force. In small scale gardens, you can also create a wind break to further protect young transplants from the wind, but this is not practical on a large scale.
Soil Temperature and Warm Season Veggies
Tomatoes can be transplanted when the soil temperature is 55 degrees F. For peppers, cucumbers, melons and squash the soil should be at least 60 degrees. Our soil temperature is high enough now that it is safe to plant most warm season crops.
Remember to check out the Kansas Mesonet resource. You can access current and historic soil temperatures to help you plan your garden calendar.
FRUIT
Integrated Approach to Fruit Tree Care
Success in the landscape begins with good cultural care. For fruit trees this means cleaning up debris, proper pruning, minimizing weeds, planting in the right location and providing supplemental water as needed. Even with the best cultural care there are times where spray treatments are necessary, but healthy trees are better able to stand up to the stress from diseases and pests.
At this time of year, you can do all the cultural care right and still have problems with disease and pests on fruit trees. Starting a spray schedule in April and May is often necessary to prevent problems such as cedar apple rust. The fungicide you use will change from spring into summer and organic options are available. Check in with your local Extension agent for a recommended spray schedule.
TURF
Spring Fertilizer Application for Cool Season Turf
Lawns should typically be fertilized when they are actively growing. Cool-season grasses such as Kentucky bluegrass, tall fescue and perennial ryegrass benefit from being fertilized in fall and late spring. The fall application is important as it helps the turf build up food reserves enabling it to green up earlier in the spring. Cool-season grasses usually have a flush of growth in mid-spring using up much of the stored energy. By applying fertilizer shortly after this growth, the turf is able to replenish the depleted nutrients ensuring the plants are strong heading into the stress of summer. A slow-release nitrogen fertilizer is best for the May application. Liquid or dry fertilizer are fine, though dry tends to be easier for homeowners to apply.
Warm-season grasses such as bermudagrass, buffalograss and zoysiagrass should be fertilized in late spring and/or summer. https://bookstore.ksre.ksu.edu/pubs/mf2324.pdf
Always read the fertilizer label for the correct rate and specific instructions.
Sweep dry fertilizers off hard surfaces and back onto the lawn to prevent it from washing into storm drains polluting our waterways.
Water after applying fertilizer if rain is not in immediate forecast.
PESTS
Bagworms – Too early to spray!
Mid to late June is typically the best time to treat for bagworms but if you had bagworms last year, you’re likely antsy to prevent their return. If there are empty bags on trees and shrubs in your landscape, it is likely you will have bagworms this year as well. Treatments for bagworms should not be done until most or all of the larvae have hatched. For now, if you see young bagworms, you can manually remove and destroy them. Treatments will be largely ineffective right now.
Cucumber Beetles and Bacterial Wilt
Description: Cucumber beetles can either be striped or spotted. Striped cucumber beetles are more common with ¼-inch long bodies, black head and antennae, straw-yellow thorax and yellowish wing covers. There are three parallel longitudinal black stripes down the body. Spotted cucumber beetles have 12 black spots on the wing covers with yellow on the underside of the abdomen.
Life Cycle: There are two generations of cucumber beetles each year. They overwinter as adults. After mating the females lay eggs in the soil at the base of cucurbit plants making it easy for larvae to feed on roots when they emerge. Two to three weeks later the larvae pupate in the soil giving rise to the second generation later in the growing season. It takes about four to six weeks for a single generation to go from egg to adult.
Damage: Cucurbit plants are targeted by cucumber beetles whose feeding reduces growth and can cause plant death. Young pumpkin and squash plants are common targets. Holes in leaves, stems, flower and fruits caused by feeding can affect yield. Cucumber beetles also transmit the disease, bacterial wilt, which causes sudden browning and death of cucumbers and muskmelons. Once infected the plant cannot be cured making prevention key.
Control: Protect young plants now by using row covers, cones or another physical barrier. Seal the edges of the barrier to prevent beetles from entering. Use transplants which can stand up to bacterial wilt better than seedlings. Mulch with straw around plants to create a habitat for predators such as wolf spiders. Remove crop debris after each growing season and manage weeds. Monitor plants regularly and manually remove cucumber beetles. Sticky cards can be used to help monitor for pests present in the garden.
Insecticides with permethrin (Bonide Eight Vegetable, Fruit & Flower Concentrate and Hi Yield Garden and Farm Insect Control) can be used when pollinators are not present. Always follow all label instructions and only use insecticides in combination with proper cultural controls.
Read more at our KSRE Publication: Striped and Spotted Cucumber Beetle
Eastern Tent Caterpillar
Description: Native to North America, Eastern tent caterpillars are hairy and black with a white stripe down the back and yellow/brown stripes on the sides along with blue, oval-shaped spots. Caterpillars create a tent-like nest that can be a foot or more in length. Full-grown caterpillars can be 2 to 2 ½ inches long. The adult moths have reddish-brown wings with two whitish bands across the forewing. The eggs, laid in masses, are covered with a shiny, black material enclosing the eggs. Cocoons are one-inch in length and white or yellowish in color.
Life Cycle: Caterpillars emerge in early March when buds begin to break. They create a silk tent in a tree crotch with many other caterpillars to create a colony. Mature caterpillars leave their nest to seek a safe place to pupate. About three weeks later the adult moth emerges. Upon mating, females lay masses of 150 to 400 eggs on branches to overwinter and hatch the following spring. There is one generation per year.
Damage: Caterpillars emerge from their tents when it is not too hot or raining, usually early morning and evening to feed on leaves. Defoliation may not kill trees and shrubs directly, but does put the plants under stress as photosynthesis is reduced. The silky nests in the trees are unsightly.
Control: Scout for egg masses during winter to remove and destroy. Dispose of tents as they appear in spring. Exposing young caterpillars makes them susceptible to predators such as birds though mature caterpillars are less appetizing due to the hairs present. Bt (Bacillus thuringiensis subsp. kurstaki) or Spinosad can be used to kill young caterpillars. Mature caterpillars can be treated with pyrethroid-cyhalothrin or permethrin insecticides, but be aware these will harm beneficials as well. Do not use these products when pollinators are active. When inside the tents, caterpillars are protected so insecticides applied at this time are much less effective.
TREES
Suckers on Trees
In spring some trees send up growth, known as suckers, from the base of the tree or roots. Suckers can develop several inches to several feet from the trunk of the tree and can be an indication the tree is under stress. However, some species are just more prone to sucker growth regardless of the health of the tree.
Not only are suckers unattractive but they deplete energy from the tree so removal is recommended. Use pruners to clip suckers at the base where they are attached to the main tree. If the cut is not made at the point of origin and a stub is left intact it will likely cause branching and exacerbate the problem. If there are minimal suckers present, removal can be delayed until early summer when regrowth is less likely. Herbicides should NOT be used to treat suckers.
Storm-Damaged Trees
Much of Kansas experienced heavy winds and rain over the past week or will at some point this season. Here are recommendations for managing storm-damaged trees.
Not all trees should be salvaged. Trees with bark that has split and exposed the cambium or those where the main trunk has split are not likely to survive. Trees with so many broken limbs that the structure is altered may best be replaced. Though these trees may produce new growth, they are under such extreme stress they are much more susceptible to diseases/pests and can be dangerous due to increased risk for further breaks.
Prune broken branches to the next larger branch or the trunk. Do not cut flush with the trunk, but rather to the collar area between the branch and the trunk. Cutting flush to the trunk creates a larger wound that takes longer to heal.
Cut back large limbs progressively. The first cut should be made on the underside of the branch about 15 inches away from the trunk. Cut up about one-third of the way through the limb. The second cut should be made on top of the branch but about two inches further away from the trunk creating an angle when joined with the first cut. This will cause the branch to break away. The third cut should be made at the collar to remove the resulting stub.
MISCELLANEOUS
What to do about a hard crust layer on the soil surface
Heavy downpours of rain often lead to soil crusting. Intense rainfall can disperse soil into small particles. When the soil dries quickly it seals the particles together creating a concrete-like layer. Young seedlings struggle to break through the crust and consequently die. The crust layer also creates a problem for drainage since water is no longer able to penetrate.
To prevent soil crusting, keep the soil covered. During the off-season grow a cover crop for the nutrient benefits as well as to protect the surface from the impacts of heavy rain. Increase organic matter content and till as little as possible or not at all. Organic matter improves the texture making the soil less susceptible to crusting because the particles of soil are not easily displaced.
To remediate soil that has a crusty layer, cultivate lightly to break up the hard surface. While there is a risk of damaging existing plants if done carefully, it is much less harmful than the effects of crusted soil.
Useful Resource: K-State Extension Wildlife Management Website
May is Gardening for Wildlife month and we have a wonderful resource available through K-State Extension Wildlife Management. Find research-based information for gardening with wildlife by creating habitats to meet their needs. Check out the podcast “Fins, Fur and Feathers” hosted by Extension specialists, Drew Ricketts and Joe Gerken, YouTube guides and more at
KSRE Wildlife Management.
QUESTION of the WEEK
“I was at the park yesterday and saw these little bugs crawling all over the place. What are they?”
These are the larvae of ladybird beetles, more often referred to as “ladybugs”.
Adult and larvae of the ladybird beetle are beneficial insects. They feed on pests such as aphids, mealybugs, whiteflies and scale and do not harm garden plants. The larvae may look menacing, with the orange and black markings on their bodies but they are effective at managing garden pests.
Contributors:
Cynthia Domenghini, Instructor and Horticulture Extension Specialist
Kansas Garden Guide
Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
For questions or further information, contact your local extension agency.
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K-State Research and Extension is committed to making its services, activities and programs accessible to all participants. If you have special requirements due to a physical, vision or hearing disability, or a dietary restriction please contact Extension Horticulture at (785) 532-6173.
Cynthia Domenghini, Ph.D.
Instructor; Horticulture Extension Specialist
Department of Horticulture and Natural Resources
Kansas State University
1712 Claflin Rd.
Manhattan, KS 66503
785-340-3013
[email protected]
