Strawberry Crop Survives

I recently received an email from Barclay Poling, Extension Specialist with NCSU. He wanted everyone to know that the strawberry crop not only survived the Easter freeze but it is an excellent crop. Please read his announcement for the latest update.

Sprinkler Irrigation and Row Covers Pull Strawberry Crop Through Easter Freeze - Farms are Now Open -- Pull Out Your Shortcake Recipe!

Barclay Poling, Small Fruit Extension Specialist (NCSU)

Monster Freeze.
On the Tuesday before Easter (April 3), I got my first glimpse from a National Weather Sevice advisory of a "monster freeze" headed towards North Carolina on Easter Weekend. The strawberry crop had been on such a wonderful track in March and early April. Everything was falling into place for a great season, including the potential for our earliest opening ever on Easter weekend. But, as everyone now knows, Easter weekend was dreadfully cold, and the state's fruit growers, including the strawberry producers, were confronted with the prospect of losing everything. The Easter weekend arctic freeze had temperatures in the teens and low 20s, as well as unbelievable winds gusting in excess of 25 mph. The North Carolina apples and peach industries were some of the hardest hit, and hardly a flower bud survived.

The outcome for NC’s strawberry growers was fortunately much better.
We prayed a lot, drank gallons of coffee to stay up for 5 straight nights of frost protection starting on Good Friday, and also used a relatively new technology that involves the use of spunbonded polypropylene row covers which look like a huge white blanket. These lightweight "blankets" literally float on top of the entire crop and help insulate and protect the berry plants from freezing temperatures. Row covers can be used to protect low-growing crops like strawberries and vegetable transplants, but sadly not grapes, fruit trees and blueberries.

Cold protection technologies save NC Strawberry Crop.
The use of these technologies that are specifically designed for low-growing crops helped the state’s strawberry growers preserve almost all of the crop; with the exception of some areas of the mountains where it was brutally cold – some areas got down to 10 F on Easter morning! But the overall outlook for the 2007 strawberry crop in North Carolina is excellent! Growers across eastern NC, the sandhills and piedmont are NOW open to the public for picking. Don’t miss out on picking some extra yummy NC strawberries this spring, and be sure to pull out your shortcake recipe!

North Carolina Strawberry Information

Update on Frost Damage

I hope everyone was able to get out this weekend and see all the damage and recovery occuring in our gardens. The picture to the left is a perfect example of Dogwood leaves with frost damage. I believe we will see alot of these symptoms throughout the rest of the year.

I have also heard a few good reports that hostas are beginning to push up new healthy leaves through the damaged leaves. Keep an eye on woody trees and shrubs. We should see new growth on those in the next week or so, I hope. You should be able to scratch the bark to see that the cambium layer is still green and these trees are still alive. Wait another week until you start to prune the dead tissue.

Boxwood Leafminer

The boxwood leafminer is the most commonly reported pest of boxwoods in North Carolina. Accidentally introduced from Europe, this small fly seems to prefer American boxwood, although English and Japanese boxwoods are also susceptible.

Boxwoods infested with this leafminer develop blisters on the lower leaf surface. Infested leaves are usually smaller, off-color and drop sooner than healthy leaves. Heavily infested boxwoods usually have sparse foliage and poor color. Shrubs are generally not killed by leafminers.

To control leafminers, foliar applications of pesticide should be applied during the adult egg-laying period which is during April and May in Western North Carolina. Adult leafminer flies emerge over a two-week period in early spring just after the boxwoods have put out their new growth. These flies are like tiny, orange mosquitoe-like (about 1/8 inch long) insects which swarm around or cling to boxwoods. After laying eggs in the leaf tissue, the flies die. There is one generation per year.

Tiny, whitish maggots hatch and feed inside the leaf. As they grow (up to 1/8 inch long), the maggots become bright yellow. Several maggots may develop in a single leaf. Their feeding induces the formation of blisters on the lower leaf surface inside of which the maggots develop for about a year.

Products approved for home use are:

imidacloprid (Merit) 75% wettable powder:
0.7 to 1.4 level teaspoons per foot of shrub height in no less than 10 gallons of water per 1000 square feet (Use as soil drench.) May also be used as spray at shoot expansion.

Malathion
Spray during female oviposition period

Eastern Tent Caterpillar

I have already begun to see the familiar nests of the Eastern Tent Caterpillar around Haywood County. This insect, although not extremely destructive, causes unsightly nests in the croches of several tree species.

BIOLOGY
Eastern tent caterpillars are found throughout eastern North America. Wild cherry, crabapple and apple are the usual hosts of the eastern tent caterpillar, but many other kinds of trees are occasionally infested. Eastern tent caterpillars feed in groups and may completely strip the new leaves from trees. The tents are unattractive as well. Trees defoliated for several years by eastern tent caterpillars may decline noticeably. Although the caterpillars are not harmful to man, many people find them to be repulsive as the caterpillars crawl about seeking places to spin their cocoons.

Only one generation of eastern tent caterpillars develops each year. In spring as new leaves develop, the caterpillars leave the eggs and begin to feed and spin silken webbing. After about two days, they begin weaving a tent in a crotch of a branch. As the caterpillars grow, they spin successive layers on the tent. In good weather, the caterpillars leave the nest several times each day to feed. In bad weather, the caterpillars remain in the nest. About 6 weeks after hatching, the caterpillars leave the nest and crawl to spin their cocoons on fences, tree bark, buildings or debris.

Once inside the cocoon, the caterpillar develops into the pupal stage. In early summer, adult moths molt from the pupal stage and emerge from the cocoons to mate and lay eggs. The caterpillars develop inside the eggs, but they do not hatch until the following spring. They spend the summer, fall, winter and very early spring inside the egg mass.

Control
Because eastern tent caterpillars spend the winter inside the egg masses, one effective method of controlling the caterpillars is to remove and destroy the egg masses before the caterpillars hatch. If the caterpillars have already hatched, the tents can be pulled down with a stick and the caterpillars crushed or otherwise destroyed . Never use fire to destroy eastern tent caterpillars as fire is extremely dangerous. Fire may damage the tree and endangers the operator and nearby property. The following pesticides are a few of those suitable for use to control eastern tent caterpillars on ornamental plants. Be sure to follow the directions for safe use found on the label of whichever pesticide is selected. Treat foliage nearest web.

acephate (Orthene) 9.4 EC
carbaryl (Sevin)

For more information, contact your local Extension office.

Hemlock Woolly Adelgid - Treatment update

Recent research has shown the soil drenching method to control the Hemlock woolly adelgid is proving to be the most effective treatment option for homeowners. Soil drenching involves the mixing of imidacloprid with water and pouring the mixture around the base of the tree into a trench 2-3 inches deep, 1 ft. from the trunk. Follow the label regarding how much water to use. Take necessary precautions to prevent run off. Rake back any heavy leaf litter or mulch on top of the ground before making the application. Return the leaf litter or mulch after the application is made. This is not a recommended method for stream bank trees.

Imidacloprid can be purchased under trade names such as Bayer Advanced Tree & Shrub Insect Control®, Merit®, Imidipro®, Touchstone®, Zenith®, and Lesco®.

For more information contact your local Extension office.

Dealing with cold injury in our gardens

As far as assessing the damage from what happened last week, only time will tell? I know that many of the perennials (daylilies, sedum, hostas, etc.) in my own yard had already begun to put out new growth. And yes, this growth was probably quite tender.

You may have tried to cover plants with sheets, overturned plastic pots, or a thick layer of pine straw. This works well by holding some of the heat that builds up in the soil, and also insulating against cold winds. Some damage may still occur, but less than you would have otherwise.

For those plants that were exposed, scout around over the next couple of weeks to look for damage. Freeze damage on woody plants is usually seen as leaf browning and then leaf drop, or a blackening of a portion of the stem. Perennials show leaves that are droopy and seem to be almost white. I believe most of our perennials that were damaged will resprout with new leaves.

Regardless of the symptoms of freeze damage, all pruning of affected parts of woody plants should be delayed until after the danger of frost is past. Not only is there increased risk of infection when pruning before then, but the old plant material provides protection to areas lower on the plant which may not have been affected. When pruning freeze damage from a plant, prune back to healthy tissue.

April Garden Reminders

Lawns

• Do not fertilize cool season grasses until September.

• Mow cool season grasses to 2 ½ – 3 inches in height.
  

• Allow clippings to stay on the lawn, they will add nutrients to the soil.

Ornamentals

• Do not remove foliage from spring bulbs until the leaves die down at least half way on their own.

• Fertilize shrubbery beds and flowering perennials.

• Apply a fresh layer of mulch no more than 3 inches deep.

• If spring flowering shrubs need to be pruned, do so within a month after the flowers fade.

Vegetables

• Plant cold tolerant crops such as cabbage, broccoli, greens, carrots, and onions.

• Seeds for tomatoes and peppers can be planted inside now, do not put them in the ground until the second week of May.
  

• Do not plant seeds of cucurbits, beans, or corn until the soil temperature is at least 65º.

Misc.

• The average last frost date for Henderson County is around April 25 and around May 15th in Haywood County, be weary of planting tender plant material until after these dates.

How to protect your plants from low temperatures

The next few nights are being forcasted to have extremly cold temperatures below freezing. You may choose a few of the following ideas to help protect growing tender plants from frost injury.

• Mulch the plants before you cover them.
• Pile dry leaves, compost, or mulch around the plant to a height of around 2 to 3 feet.
• Cover everything with a sheet, blanket or freeze cloth. Anchor the cloth to the ground with 2 x 4's or bricks. You do not want the wind to blow the ground heat from under your cover.
• If you choose to use plastic, put it on the outside. Don't let plastic touch the leaves or you will get leaf burn everywhere the plastic touches the plant.
• Remove the covering the next day if the temperature is expected to get up into the 50's.

Hemlock Woolly Adelgid

Hemlock Woolly Adelgid calls continue to increase. For information on how to identify and control this insect, take a look at the following publication:

Hemlock Woolly Adelgid

Treatment Options