Horticulture 2021 Newsletter No. 16

Horticulture News - KSRE

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REMINDERS
Do not remove foliage from spring-flowering bulbs until the foliage dies. You need to give time for the foliage to transfer energy to the bulbs.
Repot houseplants as needed. Go up 1 inch to 2 inches in size of pot.
Keep newly planted trees & shrubs watered as needed. Keep soil moist but not waterlogged.

TURFGRASS
Keep Mower Blades Sharp
Lawn-mowing season is here. Remember that dull blades give the lawn a whitish cast. A dull blade does not cut cleanly but rather shreds the ends of the leaf blades. The shredded ends dry out, giving the lawn that whitish look. A sharp mower blade is even more important when the turf starts putting up seed heads next month. The seed head stems are much tougher than the grass blades and more likely to shred. Under normal use, mower blades should be sharpened about every 10 hours of use. (Ward Upham)

Orchardgrass in Tall Fescue Lawns
Orchardgrass often infests tall fescue lawns. Unfortunately, orchardgrass is lighter green and faster growing than tall fescue, so it is very visible. Homeowners complain of the light green tufts of grass wherever this weed has become established. Even worse, there are no herbicides that will kill the orchard grass without also killing the turf. About the only good thing about orchardgrass is that it is a bunch grass and does not spread.

Orchardgrass often comes in as a contaminant in grass seed, especially K-31 tall fescue. Buying good grass seed is the first line of defense against this weed. Orchardgrass is a pasture grass and therefore is not found in the “weed seed” portion of the seed label. Rather, orchardgrass will be listed as “other crop seed.” Try to buy grass seed that has 0.0% “other crop seed.”

Control options are few and painful. Use glyphosate (Roundup, Killzall Weed and Grass Killer, Kleeraway Systemic Weed and Grass Killer and others) to spot spray orchardgrass clumps. Any lawn grasses you hit will be killed, so keep the spots sprayed as small as possible. Wait until the spots have turned brown and then cut out the clumps and replace with a small piece of sod. Large numbers of orchardgrass clumps may mean it is more practical to kill the entire lawn and start over. This should be done in the fall rather than now.

For information on identification of orchardgrass, including images, go to:
http://kswildflower.org/grass_details.php?grassID=15 (Ward Upham)

FRUIT
Fertilizing Strawberries and Brambles
Most garden soils in Kansas have adequate levels of all nutrients other than nitrogen IF the area has been fertilized in the past. However, it is recommended that a soil test be done to be sure of the nutrient needs of your fruit planting. If the soil test recommends phosphorus and potassium, use a 10-10-10 fertilizer or 12-12-12 instead of what we recommend below but triple the rate. For example, instead of ½ cup per 10 feet of row, use 1.5 cups per 10 feet of row.

Strawberries (June-Bearing): June-bearing strawberries are not fertilized in early spring as this can make the berries soft and more prone to rot. Fertilize at renovation and again in late August to early September. In most cases, strawberries need primarily nitrogen, so the recommendations are for a high nitrogen fertilizer such as a 27-3-3, 29-5-4, 30-3-3 or something similar. Though recommended for lawns, these fertilizers will also work well for strawberries as long as they do not contain weed killers or crabgrass preventers. Apply ½ cup for every 10 feet of row. Note: For more information on renovating strawberries, see page two at http://www.bookstore.ksre.ksu.edu/pubs/mf598.pdf
Strawberries (Everbearing or Day-Neutral): Fertilize in the spring as growth starts and again in early August. Use the rates recommended for June-bearing strawberries. Everbearing (dayneutral) strawberries are not renovated.

Brambles (Blackberries and Raspberries): In most cases, brambles need primarily nitrogen, so use a high nitrogen fertilizer such as a 27-3-3, 29-5-4, 30-3-3 or something similar unless a soil test directs otherwise. Though recommended for lawns, these fertilizers will also work well as long as they do not contain weed killers or crabgrass preventers. Apply ½ cup for every 10 feet of row. Fertilize in spring as growth begins. (Ward Upham)

VEGETABLES
Asparagus Beetles
Asparagus should be doing well now that it isn’t being frozen back all the time. That won’t hurt the plant, by the way. You will lose the spears that were frozen but the plant is fine. However, be on the lookout for asparagus beetles. Both the adult and larvae of asparagus beetles feed on asparagus spears by chewing the tips and spear surfaces, leading to scarring and staining of the spear tips. Asparagus beetles overwinter as adults in trash near the garden. The adults are a blue/black beetle with a red prothorax with yellow spots. The larvae are a soft, greenish grub. Small, elongated, black eggs — sticking out long ways from the side of asparagus spears — are laid on developing spears.

Early control of beetles is important to reduce feeding damage later. Permethrin will provide control but requires a 3-day waiting period between spraying and harvest. Permethrin is found in Garden and Farm Insect Control and Eight Vegetable, Fruit & Flower Concentrate. (Ward Upham)

Rhubarb Harvest and Seedstalks
Rhubarb, like asparagus, is a perennial vegetable. It is harvested for the leaf stem, which is also called a petiole. Some years rhubarb will produce large, hollow-stemmed seedstalks that arise from the center of the plant. These should be broken or cut out as they appear so that energy will go into plant vigor rather than seed production. It will take several weeks for all the seedstalks to appear so be vigilant in removing them. Newer varieties of rhubarb are selected for vigor, bright red-colored stalks and less of a tendency to produce seedstalks than the older types. (Ward Upham)

Fertilizing Cole Crops
If you planted cole crops such as cabbage, broccoli and cauliflower earlier this spring and made it through our earlier cold snaps, they will need a little fertilizer boost. These plants need to mature before summer heat arrives, so they must grow quickly while the weather is cool. A sidedressing of fertilizer about 3 weeks after transplanting helps plants continue to grow rapidly.

Use fertilizers high in nitrogen for sidedressing such as nitrate of soda or blood meal at the rate of 1/3 cup per 10 feet of row. You may also use lawn fertilizers that have close to 30 percent nitrogen such as a 30-3-4 or 29-5-4 but the rate should be cut in half to 3 tablespoons per 10 feet of row. Do not use lawn fertilizers that have weed killers or preventers. Fertilizer must be watered in if timely rains don’t do that job for you.
We have a sheet available that gives recommendations on how to sidedress specific vegetable crops. It can be found at: https://tinyurl.com/j2ggaa6 http://www.hfrr.ksu.edu/doc1991.ashx (Ward Upham)

Red Plastic Mulch and Tomatoes
Plastic mulches have long been known to provide advantages for the vegetable grower including earlier fruiting, increased yields and weed control. More recently advantages have been noted for colored mulches over the more traditional black plastic mulch. With tomatoes, the color of choice has been red. Though normally there is an increase in production of marketable fruit with red mulch over black mulch, the amount of the increase varies with the type of year we have. There may be no increase during years of near-perfect weather or up to a 20% increase with less favorable growing conditions. A good average expected increase is about 12%.

So, how do you apply plastic mulch? Commercial growers have a mulch-laying machine that applies the trickle (drip) irrigation line and the mulch in one operation. Home gardeners must do this by hand. The first step after soil preparation is to place a trickle line near the center of where the mulch will lay as the plastic will prevent rainwater or overhead irrigation from reaching the plants. Then construct trenches for the outer 6 inches of the plastic mulch. This allows the center of the bed to be undisturbed with the edges of the mulch draping down into the trench. Fill the trenches to cover the edges of the mulch. This will prevent wind from catching and blowing the mulch. If the soil has been tilled, a hoe is all that is needed to prepare the trenches. (Ward Upham)

PESTS
Eastern Tent Caterpillar
The larvae (caterpillars) of the Eastern tent caterpillar, Malacosoma americanum, are emerging (eclosing) from their eggs and feeding on the leaves of trees and shrubs. After caterpillar’s emerge from the eggs, they create a distinct white, silken nest (or tent) in the branch crotches of trees and shrubs including: birch, crabapple, hawthorn, mountain ash, poplar, willow, and flowering cherry, peach, and plum. The nest protects caterpillars from cold temperatures and natural predators.

Caterpillars are black and have a white stripe extending the length of the body along with blue markings on both sides of the body. There are five larval instars (stages between each molt). Eastern tent caterpillar is one of our earliest caterpillar defoliators in the season, feeding on newly emerged leaves, which can reduce the ability of trees and shrubs to produce food by means of photosynthesis.

Although feeding damage may not directly kill a tree or shrub, a decrease in photosynthesis can predispose plants to secondary pests such as wood-boring insects. Leaf quality can influence tree and shrub susceptibility. For instance, black cherry, Prunus serotina, trees grown in the shade are fed upon less by Eastern tent caterpillars due to lower leaf nutritional quality. The young or early instar (1st through 3rd) caterpillars are active during the daytime and reside in the silken nest at night. During the day caterpillars emerge from the silken nest and feed on plant leaves. On over-cast or cloudy days caterpillars will remain inside the silken nest. The final instar (5th) caterpillar only feeds at night. The length time of time that caterpillars spend feeding increases 4-fold between the 1st and 5th instars.

Feeding activity depends on temperature with caterpillars feeding for a longer period of time when exposed to warmer temperatures than cooler temperatures. Eastern tent caterpillar overwinters as an egg mass attached to the branches or small twigs. There is one generation per year in Kansas.

The silken nests can be physically removed or disrupted by hand. You can destroy, disrupt, or open-up the silken nest using a rake or a high-pressure water spray. The young exposed caterpillars are susceptible to consumption by birds. However, the later instars are fed upon less because the hairs on the body deter birds from feeding on them. Spray applications of the bacterium, Bacillus thuringiensis subsp. kurstaki, or spinosad are effective in killing small (young) caterpillars and suppressing minor infestations of Eastern tent caterpillar.

These insecticides are stomach poisons so caterpillars must ingest the material to be negatively affected. When caterpillars are mature and approximately 2 inches long, then pyrethroid-based insecticides, such as bifenthrin, cyfluthrin, and lambda-cyhalothrin should be applied. It is important to apply insecticides when caterpillars are active during the daytime to increase exposure to the insecticide. However, pyrethroid-based insecticides are harmful to pollinators (e.g. honey bees) and beneficial insects. Therefore, do not apply pyrethroid-based insecticides when pollinators are active. For more information on managing Eastern tent caterpillar populations contact your county or state extension specialist. (Raymond Cloyd)

Termites or Ants
Both termites and ants are able to swarm and may have wings during part of their lives. Since these insects are close to the same size, people often misidentify flying ants as termites. Since flying ants do not attack wooden structures like termites, it is helpful to be able to tell the difference.

Fortunately, there are several differences that can easily distinguish the two. For example, ants have a thin waist; the waist of a termite is thick. Also, ants’ antennae are elbowed, while termites’ are curved. Thirdly, termites have two pairs of wings that are of equal length. Ants also have two pairs of wings, but theirs are of unequal length. Homeowners who find signs of termite activity should shop for a reputable pest control firm. (Ward Upham)

Contributors: Raymond Cloyd, Extension Entomologist; Ward Upham, Extension Associate

Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173

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Blog Post: http://www.ksuhortnewsletter.org

Video of the Week: How to Sharpen a Mower Blade
https://kansashealthyyards.org/component/allvideoshare/video/how-to-sharpen-a-mower-blade?Itemid=101

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