1712 Claflin, 2021 Throckmorton Plant Science Center
Manhattan, KS 66506 (785) 532-6173
Video of the Week: Stake and Weave Tomatoes
An alternative method of supporting tomatoes using metal t-posts and twine to create a hedge of tomato plants.
GARDEN CALENDAR
May Garden Calendar
VEGETABLES
Supporting Tomatoes
Tomatoes need support to remain upright, improve air flow and reduce the risk of disease. Support keeps the fruit off the ground which helps reduce contamination from contact with soil. Traditional, store-bought cages can be effective for small, container tomato varieties but are often insufficient for most tomato varieties.
You can build a stronger tomato cage using concrete reinforcing mesh. Multiple cages can be built with a roll 150 feet long and 5 feet tall. The openings between the wires are large enough to fit your hand through for harvesting and allow even large slicing tomatoes to slide through. Cut the wire at the desired length and create a cylinder that will wrap around the tomato plant. If you cut the wire to six-feet long, the diameter of the cage will be almost two feet. Wrap the cut wires around the other end of the panel to make a cylindrical shape. Secure the cage by attaching it to multiple wooden stakes hammered into the soil several inches.
FRUIT
Peach Leaf Curl and Plum Pocket
One of the most common diseases of peach trees in Kansas is peach leaf curl. Infected new leaves develop reddish areas and eventually drop. Plants use their energy to send out new leaves which inhibits fruit production and overall tree growth. Plum pocket is a disease that distorts the fruit and prevents seed growth leaving the plums hollow and enlarged.
Applying fungicide in the fall after leaves have dropped can be an effective control against these diseases. But for now, maintaining healthy trees is the best way to prevent problems with your fruit trees.
A healthy peach/plum tree will have large, deep green leaves with 18-24 inches of new growth from last year. If you see less than 12-inches of growth you can apply a balanced fertilizer (such as 13-13-13). Add 1-1/3 to 2 cups on the soil beneath the tree canopy. This should be done as soon as possible to promote leaf growth. Thinning the fruit can also help direct the tree’s energy to growth.
Newly Planted Strawberries
During the first year, strawberries rely on adequate soil moisture for survival, root development and formation of runners and fruit buds. Provide about one-inch of water per week during the growing season and up to two-inches per week in July and August.
Remove blossoms from newly planted spring-bearing plants. This will direct energy to plant development. Plants that are allowed to fruit during the first year will still develop runners, but they will not be as strong which will negatively impact next year’s fruit. Focusing on developing runners during the first year is necessary to produce a large harvest in the future.
Remove blossoms from newly planted everbearing plants during the first four to six weeks after planting to promote root growth.
PESTS
Cabbage Worms
Description: Velvet-green larvae are 1-1/4 inches long at maturity. The chrysalis is light green, tan or yellowish and about one-inch long. The adult is a white butterfly with black spots on the wings. Spherical eggs are yellow to cream in color.
Life Cycle: Adult butterflies emerge in spring and begin laying eggs on the underside of leaves of host plants. The resulting caterpillars reach maturity within 10-14 days and feed on hosts of broccoli and cabbage typically. Chrysalis attach to the food source with silken threads. There can be multiple generations of cabbage worms each year.
Damage: No damage is caused by the adults but the larvae feed on their host plant and can defoliate entire plants sometimes preventing the formation of heads. Boring into cabbage heads can also make them inedible.
Control: Monitor plants for signs of cabbage worms regularly. White butterflies near cole crops indicates the presence of cabbage worms. Larvae are camouflaged against plant leaves so look for irregular-shaped holes and dark green fecal pellets on the plant or ground nearby.
Prevent cabbage worms by removing debris after the growing season to reduce overwintering habitats. Use row covers to prevent butterflies from laying eggs. Choose cultivars that mature faster to shorten the season. Remove larvae by hand. Bt (Bacillus thuringiensis) is effective on young caterpillars as are Spinosad, neem and pyrethrum. Always follow label instructions and practice safe application. A spreader sticker will increase efficacy due to the slick leaves of the host plants.
Rabbits in the Garden
Though many shrubs that are two-three feet tall can tolerate feeding from rabbits, annuals and young herbaceous plants can be decimated overnight.
Exclusion is usually the most effective tactic for preventing damage caused by rabbits. Creating a fence around your plants with a wire mesh such as chicken wire or using a floating row cover can provide protection. Fences should either be buried several inches below ground or secured to the ground with stakes to prevent rabbits from pulling them up and squeezing under the fence. Fences should be at least 2-3 feet tall. Young trees and shrubs may need protection for several years before they are mature enough to withstand feeding from rabbits.
Though repellants exist, they are often not as effective as gardeners hope and are typically not labeled for vegetable crops. They also must be reapplied each time it rains.
Motion sensor sprinklers and noise makers can be used to scare wildlife out of the landscape but this strategy also has limited efficacy due to their restricted range and because rabbits can become accustomed to them.
Colorado Potato Beetle
Description: Adult beetles are about 3/8-inch long with yellow/cream to orange bodies with black stripes on the wings. Their bodies are oval-shaped. Larvae are dark red with two rows of black dots on the sides of their bodies. Mature larvae are about ½-inch long.
Life Cycle: Adults overwinter in the soil and emerge in May. After feeding for up to ten days, they mate and females lay eggs in clusters of up to 40 yellow-orange eggs on the bottom of potato leaves. In three to ten days, larvae emerge and feed on the leaves. After several weeks, larvae burrow into the soil and pupate. The life cycle is complete in about 21 days and there can be three generations per year.
Damage: Adult beetles and larvae feed on the leaves of potato, tomato, eggplant, pepper, tobacco and other solanaceous plants causing damage and stunting. Large infestations can completely defoliate plants. Mature larvae consume the most and cause the greatest damage. Yield can be affected depending on the timing and extent of leaf damage.
Control: Begin scouting for beetles weekly early in the season. Look for egg clusters under the leaves. Eradicate weeds near potato plants and practice crop rotation. Select early-maturing varieties of potatoes. Drop larvae and adults into a bucket of soapy water and destroy egg clusters. Beneficial insects such as lacewings, ladybird beetles, predatory stink bugs, spined soldier beetles and tachinid flies attack Colorado potato beetles.
Bt (Bacillus thuringiensis) is effective for controlling Colorado potato beetle if applied when the larvae are small. Apply every 5-7 days until all eggs have hatched and ensure thorough coverage of the host plant. Bt is safe for mammals, birds, fish and beneficial insects but Colorado potato beetle can develop resistance if used repeatedly.
Learn more from our KSRE publication: Colorado Potato Beetle
and Colorado Potato Beetle: Insect Pest of Vegetable Crops
Walnut Wilt
Description: Several species in the walnut family produce a toxin, juglone, which is formed in the leaves, fruit hulls, inner bark and roots. Juglone can be leached from the leaves and nuts into the soil with rain or released from the roots. When susceptible plants come in contact with the toxin the affected stem tissue may turn brown and plants may begin to wilt and show stunted growth.
Susceptible Plants: Tomato, potato, blackberry, apple, lilac, asparagus, chrysanthemum, peony
Resistant Plants: Red cedar, redbud, quince, black raspberry, Kentucky bluegrass, corn, bean, carrot, dandelion, zinnia, and most native hardwoods
Recommendations: Avoid planting susceptible plants near juglone-producing trees. Juglone can persist in roots for several years after trees are removed. Avoid planting susceptible plants in these areas for at least two years to avoid damage.
Bristly Rose Slug
Description: Larvae are pale-green and ½-inch long with fine, hair-like spines in clusters along the body. Though sometimes confused as a caterpillar, the bristly rose slug is actually the larvae of the sawfly; a black to yellow wasp.
Life Cycle: Adult female sawflies create slits along the edges of rose leaves and insert eggs. Larvae hatch from the eggs and begin feeding on leaves. Larvae drop to the ground to pupate on the soil surface. They overwinter as pupae and there is typically only one generation each year.
Damage: Young larvae feed on the underside of leaves causing them to appear skeletonized. As the larvae mature, they create larger holes in the leaves. Eventually they may consume the entire leaf except large veins.
Control: A strong spray of water will dislodge the larvae and make it difficult for them to return to the leaves. Insecticidal soap, horticultural oils, Spinosad (Monterey Garden Spray, Natural Guard Spinosad or Captain Jack’s Deadbug Brew) and permethrin (BioAdvanced Vegetable & Garden Insect Dust, Bonide Eight Vegetable, Fruit & Flower Concentrate, Hi-Yield Garden & Farm Insect Control) are also effective options. Always follow label instructions and research any product before use to ensure it will support your gardening goals.
TURF
Time to Fertilize Warm-Season Grasses
Turfgrasses should be fertilized when they are actively growing. For warm season grasses that time is near. Late spring/early summer fertilizer applications are ideal for bermudagrass, buffalograss and zoysiagrass. Fertilizing too early encourages cool season weeds to grow.
Northern and northwest Kansas can wait until May 30 or later to fertilize warm-season grasses, but most of the state can fertilize beginning now (mid-May). Fertilizing too late in the season (late summer) can increase their susceptibility to winter damage. Avoid fertilizing with nitrogen after August 15.
Bermudagrass needs about one pound of nitrogen per 1,000 square feet every four weeks. Zoysiagrass requires less nitrogen. Apply ¾ to one pound of nitrogen in two applications; one in June and one in mid-July. Buffalograss will survive without supplemental nitrogen, but providing it will improve the color and density of the lawn. Sometime between now and early June apply one pound of nitrogen per 1,000 square feet. If a darker green is desired, follow the same fertilizer recommendations as zoysiagrass.
If you need additional information about fertilizing your lawn, visit our KSRE publication: Fertilizing Kansas Lawns.
QUESTION of the WEEK
Help with Identifying Poison Ivy
How can I tell if a plant growing in the woods by my house is poison ivy?
Two types of poison ivy are found in Kansas. They have similar growth habits and leaf structures. Poison ivy is a woody native and can be a vine, shrub or groundcover.
The commonly referenced trait for poison ivy is the grouping of three leaflets per leaf. Individual leaflets can be one to four inches long. The middle leaflet is the only one with a long stalk while the other two leaves are closely attached to the petiole. Leaves range in their shade of green and glossy/dull surface. Leaf margins can be smooth, toothed or lobed. The shape can also vary among leaves on the same plant.
Contributors:
Cynthia Domenghini, Instructor and Horticulture Extension Specialist
Kansas Garden Guide
KSRE Entomology
KSRE Wildlife Management
Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
For questions or further information, contact: [email protected].
This newsletter is also available online at:
http://hnr.k-state.edu/extension/info-center/newsletters/index.html
The web version includes color images that illustrate subjects discussed. To subscribe to this newsletter electronically, send an e-mail message to [email protected].
Brand names appearing in this newsletter are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned.
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]
