pruning a fruit tree

Pruning

Mid-February through mid-March is a good   time to prune. When deciding what to remove make selections in this order; take out anything that is damaged, broken or diseased first, next remove branches that are crossing, rubbing, or one on top of each other, then thin as needed and look at the overall tree form. Fruit trees are usually pruned to an open vase (peaches) or a central leader (apples). When looking at form try to keep trees balanced so that there is an equal amount of wood and fruiting surface on all sides of the tree.

Planting

Spring is the best time to plant fruit trees. Bare root trees purchased locally or by mail will do best if they are planted early (late February to early March) while temperatures are still cool. Potted trees can be planted later if needed and are not as sensitive to warm temperatures as bare root trees. Prune new trees as little as possible in the first year. In most cases we like to see the lowest branches coming off the trunk at approximately 24-30 inches. Some young trees come right from the nursery already pruned. If not and your tree is a long “whip” with no branches, you may need to make a heading cut to promote branching.

Our local nurseries can recommend to you some varieties that are suited to the area. You may also click on “fruit” from our website and you will see a list of cultivars that grow well here. Keep in mind that apples and pears do not grow well in the low valley areas of St. George, where summer temperatures are hot. Peaches and apricots are not bothered by the heat and will perform well. On the other hand peaches and apricots will not do so well above 4,000 feet as cold spring temperatures will often freeze the flower buds.

Dormant Sprays

Dormant oil should be applied in later February or early March just before the buds fully open. Do not use any sprays during bloom to help protect pollinating insects. You can begin “cover sprays” once all flowers have fallen off. Cover sprays such as a “Home Fruit Spray” may be used as the label directs from the time small fruits form up until the pre-harvest period. The label will dictate how many days prior to harvest you can safely spray fruit.  This will vary depending on the chemical you are using and the type of fruit you are growing.

White Grub

Grubs can cause serious injury to turf, especially if they are found in large numbers. By September if you are experiencing grub injury you will need to step up your control measures. Products containing imidachloprid such as “Merit” are designed for season long control, but are not fast acting. Rather than treating with “Merit” in the fall, apply “Dylox” for a quick knockdown. Other chemicals such as Sevin, Malathion or Pyrethrum are usually recommended for adult grubs above ground and may be used, but in general will not give the same level of control. Keep in mind that if grubs go uncontrolled this time of year, they will spend the entire winter below the sod, coming to the surface next spring to cause further damage. For more detailed information on grub control refer to; http://extension.usu.edu/files/publications/factsheet/white-grub07.pdf.

Adult Beetle

Damage from the tobacco budworm

Tobacco Budworm

Have you noticed little holes in your petunia flowers?  They are caused by a small green caterpillar known as the tobacco budworm. The adult moth lays its eggs on the plant. After they hatch, the young caterpillars begin to feed making holes in flowers and foliage. They can quickly decimate petunias and have also been noted as a serious pest of geraniums and other flowers.

Tobacco Budworm

Tobacco budworm is best controlled by applying Bacillis (BT) to the affected plants. Young caterpillars will pick up the BT when feeding and not be able to complete their life cycle. Damage should decrease significantly within a few days. Pruning of damaged flowers and a light fertilization should stimulate new flowers to develop.

Flat-headed borer, Chrysobothris sp. is a serious pest in the SW desert. This genius of beetles contains a number of insect pests known to cause damage to trees and shrubs by boring into the wood. While protected from the elements, eggs are laid by female beetles and the developing larvae feed on the inner tissues. It is not uncommon for them to spend the entire winter inside the bark causing damage as they feed.

Damage from boring insects is common in the desert. We have identified borers in willows, locusts, ash, plum, apple, peach, and pear trees. A single borer may kill a young tree. Older trees are also susceptible, but since they have more vascular tissue it usually takes more than one borer to be fatal.

Control
Preventing stress is the key management tactic.  Ensure that plants are getting adequate irrigation (but not too much). The soil should be able to support the plants you are growing, and proper fertilization and general cultural practices should be used.  Prune out infested limbs as soon as possible to reduce the population and spread to other trees.  Chemicals can be applied as trunk and limb sprays at the time that adults are flying and laying new eggs.

Timing is important for control, but often difficult to determine. The Flat-headed apple borer for example, becomes active in June in the northern regions of the state. This would translate to late April and early May for those of us in the southwest.  Populations can sometimes be determined by the trapping of adult beetles. Trapping the insects has proven an effective monitoring tool, but does not give control by itself.

Chemical sprays are not always effective as they do not control the insect once it has gained entry inside the tree. Carbaryl, “Sevin” applied to the trunk just before the adults become active, will give fairly good control. Another approach is to use the systemic chemical Imidachloprid, “Merit”. Although, effective for some pests, we have not been able to document how effective this product is on flat-headed borer.

Be sure to read the label before buying and applying any chemicals. Not all trees appear on every chemical label. Take special care when treating fruit trees that you know which chemicals can be used and how closely they may be applied to harvest.

blossom end rot

Help your tomatoes handle the heat

Summer temperatures are beginning to take a toll on this year’s tomato crop. Tomatoes are a tropical plant which means they can handle a fair bit of heat, but also like some humidity. We always notice however a number of problems related to fruit quality when temperatures climb above 95 degrees consistently. Here are some of the most common problems.

Blossom end rot

Blossom end rot, also called “bottom end rot” is when the bottom of the tomato develops a brown scabby area. It may remain a dry patch or develop into a soft rot. The affected area may be as small as a dime or it may affect the entire bottom half of the fruit. Young, developing fruits need nutrients such as calcium to form properly. There must also be an adequate supply of water to move the nutrients out to the areas where fruit is being formed. Hot temperatures and drying winds will reduce the plants ability to provide the necessary nutrients for fruit development. The result is often blossom end rot. The best solution is to increase irrigation frequency.

Tough core

Another symptom of extreme heat is tough core of tomatoes. The area inside the fruit, just below where the stem attaches, may become hard and white. Some varieties may be more prone to this problem, although, I am not aware of any studies that have shown more problems with certain varieties. There is no cure for this problem.

Sunburn

Tomato fruit may develop a white or yellow discoloration, on the upper shoulder of the fruit, when exposed to the sun. The tissue below the skin will also become tough and leathery. Growing varieties that have more foliage may help with this problem, since it appears to show up only where there is direct contact with the sun. Shade cloth may also help.

Poor fruit set

Fruit set will generally drop off sharply when hot summer weather persists. The tomato flower is self pollinated, but needs good conditions for adequate pollination. Ideal daytime temperatures are between 70 and 85 degrees. Once temperatures are above 90 degrees consistently, fruit set will suffer. Shade cloth, placed above the plant to keep the sun off, coupled with misting may lower temperatures enough to help with fruit set. Some varieties like “Fourth of July” and “Heat Wave” will tolerate heat better than others.

Good soil preparation will go a long way toward helping your tomatoes handle the hot weather. Organic matter incorporated into the soil and mulch on top of the soil, helps retain moisture and keep soil from heating up. In addition, getting plants started early before the weather gets stressful will also help in getting through the summer heat.

Box gardening

Container Gardening

By Rick Heflebower, Horticulture Agent, Utah
Adapted from Iowa State University Extension publication PM870B

Growing vegetables in containers may be a suitable alternative when outdoor gardening space is not available. In situations where space is not an issue, but the soil is poor, growing in containers and using a good potting mix may be preferable. Adequate sunshine, water, and fertilizer plus a well-drained growing medium are essential for successful container gardens.

Containers

Almost any type of container can be used if it provides good drainage through holes in the bottom or around the sides near the bottom. If adding holes, drill four or more 1/4-inch holes evenly spaced around the container bottom. Most vegetables require containers that hold at least 6 to 8 inches of potting mix. Root crops such as carrots require deeper containers. Compact or “space saver” varieties will generally perform well in containers.

Growing media

Container gardens require a growing medium that drains well, yet does not dry out too fast. “Soilless” potting mixes have several advantages over soil. They are free of plant disease organisms and weed seeds, are less likely to compact, hold moisture and plant nutrients well, and are lightweight—making the container more portable. “Soilless” potting mixes can be purchased from garden centers and retail outlets.

Location

Nearly all vegetables grow and produce best when grown in full sunlight. Plants that bear fruit, such as cucumbers, tomatoes, peppers, and eggplant, require the most sun. Leafy vegetables (lettuce, cabbage, greens, spinach, and parsley) tolerate more shade than root crops (radishes, beets, and onions). Containers should be placed where they will receive at least 6 hours of sunlight per day. Caution, in Washington county where heat is intense during the summer months, place potted vegetables where they will be in the shade during the afternoon.

Watering

Plants grown in containers require frequent watering because they dry out quickly from sun and wind. Some plants may require daily watering. Apply enough water to reach the bottom of the container and allow the excess to drain through the drainage holes. Never allow the soil to dry out completely between waterings; this may cause the plants to drop their fruits and flowers. However, over-watering also will slowly kill plants because the roots will not receive enough oxygen. When watering, avoid wetting the leaves, especially if watering late in the day. Wet leaves encourage the development of plant diseases.

Fertilization

Container-grown plants require fertilization more frequently than field-grown vegetables because they have less soil from which to obtain nutrients. A soluble fertilizer (15-30-15 or 20-20-20) applied once every week or two is recommended. This can be applied while watering.

Tomato tips

When growing standard-sized tomato varieties, use a stake or cage to keep the vines upright. If staked, plants should be pruned to produce manageable one- or two-stem plants. To prune a tomato, remove the small shoots that form in the axils of the leaves and stems. If these shoots are not pinched out, they will grow and make the plants difficult to train. Tie the stems loosely to the stake. Tomato cages should be made of fencing material of at least 4-inch mesh so the fruit can be harvested easily. Cages should be at least 24 inches in diameter.

Tent Caterpillars

They’re Back! Tent Caterpillars are invading home landscapes

Every spring the arrival of the Tent Caterpillar brings frustration to southern Utah residents. Named for the web-like nest they inhabit, this insect creates a lot of concern in landscapes this time of year. Tent caterpillars are known to infest a variety of trees including ash, cottonwood, willow, poplar, and all types of fruit trees.

Eggs laid from the previous season begin to hatch just as the new leaves begin to come out.  Newly-hatched larvae feed voraciously on foliage and flowers. They tend to stay in clusters and often denude an entire branch before moving on. Once they have devoured the leaves of a tree, they will migrate to another in an effort to satisfy their appetite.  These young larvae will molt (shed their skin) four times over a 4-6 week developmental period. They will then go into a resting stage for about a week before emerging as a tan-colored moth. Adult moths mate, and the female will lay 100 to 350 eggs in a band on a limb. These eggs will not hatch until the next spring.

Control
In native cottonwoods, it is nearly impossible to control Tent Caterpillars. The nest is usually quite high in the tree and beyond the reach of most sprayers. Even commercial equipment may lack the pressure necessary to reach the top of large trees. The damage to large, old trees is generally minimal unless the tree is stressed or not healthy. Defoliation of a large, healthy tree is not serious as there is generally enough reserve in the tree to put on new foliage again. If the nest can be reached before the insects mature, the branch can be sawed off and the insects destroyed.  Once they leave the nest, they tend to feed during the day and return to the nest in the late evening.

A more serious problem occurs as the caterpillars leave the tree they have hatched from and begin to feed on neighboring landscape trees. If you begin to notice young caterpillars moving to landscape trees and shrubs, you can spray with a product containing “Bt” (Bacillus thuringiensis.) This “organic” insecticide is effective if used when the caterpillars are small. If they are approaching one and half to two inches, a more potent insecticide such as “Sevin” (Carbaryl) or a pyrethrum is required to do the job. Birds, bats and small mammals will feed on caterpillars and help keep natural populations in check, but they cannot control them enough to prevent landscape damage when numbers are great.

It is important to remember that Tent Caterpillars are more nuisance than anything.  The damage to most landscapes is minimal.  If your entire neighborhood is infested you should call a professional and let them locate the nest, preferably before hatch occurs!