Preventing Apple Pests
National Gardening Association Editors

Growing your own apple trees is relatively easy, but avoiding insect and disease damage to the fruit requires pruning and prevention.

Tools and Materials

• Pruning shears and lopper
• A ladder may be needed if your tree is full size
• Baited sticky traps
• Wire mesh trunk guards
• Mulch
• Hose-end sprayer
• Sprays of horticultural oil, liquid sulfur, Bacillus thuringiensis kurstaki, and perhaps phosmet (Imidan)

Prune. Prune your apple tree every winter before you detect any signs of new growth. Eliminate crossing branches, watersprouts, and crowded growth. The following pointers will help keep pests at bay.

Eliminate hiding places. Pick up and destroy fallen fruit, which may contain grubs. Remove plastic and paper tree guards, where adult flies and moths may spend the winter. Replace them with wire mesh guards. Surround trees with mulch instead of grass.

Smother with oil. In spring just before new leaves emerge, spray trees with nontoxic horticultural oil. The oil smothers dormant insects and their eggs.

Know your pests. Three common insect pests that damage apple fruits are apple maggot flies, plum curculio, and codling moth. The best time to control these pests is while they are mating and looking for potential egg-laying sites. This is just before early to midsummer, when these insects lay their eggs on or near developing fruit.

Apple maggot flies appear in June or July to lay their eggs on developing apples. When the eggs hatch, the larvae burrow into the fruit. Trap flies with sticky red spheres and bright yellow 8- by 10-inch rectangles hung in the trees at eye level. Place spheres near fruit clusters about three weeks after flower petals fall; use two traps for a small tree (8 feet tall or less), six traps for a large tree (10 to 25 feet).

Curculio is a 1/4-inch-long beetle that makes distinctive crescent-shaped scars on developing fruit. The grubs tunnel through the apples, causing the fruit to drop in early summer. To kill the adults, spray phosmet (Imidan) immediately after the blossom petals fall and again a week to 10 days later. (Wear protective clothing and avoid spraying during bee activity.) Nonchemical controls include spreading a tarp under the trees in the morning and shaking the tree to dislodge the pests. Also, raking up and destroying dropped fruit will reduce the local population of these pests over time.

Codling moths lay eggs on developing fruits shortly after petals fall in spring. Eggs hatch in a few days, and young larvae tunnel into fruits where they feed and mature, destroying the fruit in the process. The best remedy is spraying Bacillus thuringiensis kurstaki in the evening 15 days after petals begin to fall. Repeat five days later. The spray is toxic to caterpillars only.

Apple scab is a fungal disease that causes black splotches on leaves and fruit. It is most common and severe in the eastern U.S. where summer rainfall is common, but it occurs in all apple-growing regions. The first line of defense is to plant scab-resistant varieties such as 'Enterprise', 'Freedom', 'Gold Rush', 'Jonafree', 'Liberty', 'Macfree', 'McShay', 'Nova Easygro', 'Prima', 'Priscilla', 'Pristine', 'Redfree', 'Sir Prize', and 'William's Pride'.

If you've inherited a disease-prone variety, sulfur sprays can control the disease. Use liquid sulfur, spraying it over the tree once flower buds show pink. Repeat 10 days later.

Tips

To reduce the need for fungicides, choose only disease-resistant apple varieties when buying young fruit trees.

Avoid all-purpose fruit sprays because they kill many beneficial insects as well as the harmful ones.

Improving Clay Soil
National Gardening Association Editors

If your garden has heavy clay soil, you know what a challenge it can pose to plants, not to mention gardeners. Heavy clay drains slowly, meaning it stays saturated longer after rain or irrigation. Then, when the sun finally comes out and the soil dries, it forms a hard, cracked surface.

On the bright side, clay soils are usually richer in nutrients than sandy soils are. And clay's tendency to hold water tightly can be an advantage.

Here are some tips for making clay soil more manageable and easier to work.

Tools and Materials

• Soil test kit or commercial test
• Organic mulches: compost and aged manure, straw
• Wheelbarrow or cart
• Shovel
• Rake
• Cover crop (wheat, rye, clover, or oats)

Test soil pH, and adjust as necessary. Clay soils are rich in nutrients, but if the soil is too acidic or too alkaline, those nutrients won't be available to the plants. Use a home test kit or send a sample to a soil testing lab, then follow the recommendations for adjusting pH. For most garden plants, a pH of 6.3 to 6.8 is ideal. Find a lab near you by checking in your telephone directory, or by calling your local cooperative extension office.

Add organic matter. This helps improve drainage and lighten heavy soil. It also provides nutrients for beneficial soil microorganisms which will, in turn, also help improve the soil. Before planting in spring, add compost and aged manure. A 2- to 3-inch layer worked into the soil to shovel depth is a good amount. Throughout the growing season, mulch with organic materials like grass clippings, shredded leaves, or additional compost. Since soil microorganisms literally "eat" organic matter, make a habit of continually adding it to your soil.

Build raised beds. Because clay soils hold water, creating raised beds can help improve drainage by encouraging water to run off. Raised beds can be a simple mound of soil, or can be constructed out of wood, brick, or stone. To lessen compaction, size the beds so you can reach the middle without stepping in the bed.

Mulch beds over the winter. Driving rain can really pack down bare soil, so keep beds mulched with organic matter both during the growing season and over the winter. A layer of straw over the beds will protect the soil from compaction and reduce erosion; it can also help minimize weed growth. In the spring, transfer the mulch to the garden paths.

Plant a cover crop. A cover crop is like a living mulch. Different cover crops are appropriate for different regions. In the north, winter wheat and winter rye are popular choices; in warmer regions, crimson clover and oats are commonly used. For a winter cover crop, sow after the last crops have been harvested. The following spring, simply till the plants into the soil, adding yet more precious organic matter.

Tips

Improving soil takes time, so don't expect overnight results. On the other hand, if you follow the above steps you should notice some improvement each year. Within a few years, you'll have rich, plant-friendly soil.

Add compost any time. However, if you are tilling in fresh or uncomposted organic matter, such as a cover crop, leaves, or straw, wait at least a few weeks before planting to allow the material to break down.

Photography By Sabin Gratz/National Gardening Association

Removing Lawn Thatch
National Gardening Association Editors

Thatch, the buildup of dead grass between living grass and the soil, causes trouble for your lawn when it exceeds 1/2 inch thick. Excessive thatch prevents air, water, and nutrients from reaching plant roots. Cutting through and removing thatch improves your lawn's health.

Tools and Materials

• Trowel or shovel

• Tape measure

• Stiff lawn rake

• Thatch rake, or power rake or vertical mower

• Sprinkler

• Lawn fertilizer

• Grass seed (optional)

Determine depth of thatch. Remove a core of soil from the lawn with a trowel or shovel and measure the depth of the thatch, which is the layer of dead grass above the soil line. A layer that's 1/2 to 1 inch thick can be removed with a stiff lawn rake. Deeper layers may require a power rake.

Determine the best season to remove thatch. The best time to dethatch is just before the grass begins a period of active growth, which is spring for warm-season grasses such as Bermuda, St. Augustine, and zoysia. Cool-season kinds such as Kentucky bluegrass are best dethatched just before their period of most active growth, in very early spring or early autumn.

Choose method. For shallow thatch on small areas, use a stiff lawn rake. For small lawns with more than an inch of thatch, use a special thatch rake. Large areas and thick layers call for power rakes or vertical mowers, which are available from rental agencies.

Prepare lawn. Mow a little lower than usual. If needed, water the lawn to moisten the soil.

Use a thatching rake. Pull the blade-like tines across the lawn, cutting through the thatch. Work in small sections, and then remove the debris with a rake.

Use a power rake or vertical mower. Adjust the cutters to slice just through the thatch layer. Check cutter depth after first few feet. Run the machine in parallel rows over the lawn and then again at 90? to the first pass. Remove debris with a lawn rake.

Aftercare. Water and fertilize the lawn to help it recover from dethatching. To prevent thatch buildup from recurring, adjust the soil pH and alter your lawn care habits if needed (excessive use of water, fertilizer, or pesticides are common causes). Overseed with a good-quality grass seed to improve the lawn's health, vigor, and appearance.

Tips

Thatch is caused by several factors, including grass type, excessive watering, soil compaction, high or low soil pH, or overuse of fertilizer and pesticides.

Lawns with a thick layer of thatch are more vulnerable to drought, as well as to insect and disease damage. Lawns with thick thatch may feel springy underfoot.

Photography by Suzanne DeJohn/National Gardening Association.

Controlling Whiteflies and Aphids
National Gardening Association Editors

Few insect pests are more widespread than whiteflies and aphids. They attack indoor and outdoor vegetables, flowers, herbs, shrubs, and trees. They breed quickly, and once their numbers are high, they can damage leaves, stems, fruits, and even roots by sucking plant juices. Let's look at both pests and the safest controls for them.

Tools and Materials

• Pruners

• Yellow sticky traps

• Insecticidal spray: soap, horticultural oil, neem

• Hand sprayer

• Hose

An aphid's life. Aphids like the low light levels and cool conditions of spring and fall. They will attack all plant parts but prefer young, succulent growth. There are many species of aphids, some named after the plants they attack, such as pea aphids and peach aphids. In general, all are small (1/16 to 1/4 inch long) and oval-shaped, and can be black, white, green, or pink. Although most aren't very mobile, some forms have wings. All reproduce quickly, and under the right conditions a small number can bloom into a major infestation in no time. By sucking plant juices from leaves and stems, they weaken the plant. More seriously, they can transmit virus diseases that gradually debilitate and kill some plants.

A whitefly's life. In cold-winter climates, whiteflies are mostly greenhouse or indoor pests, but they can be found in the garden. In mild-winter climates with no winter cold to kill them, whiteflies are serious outdoor pests. In recent years in the Southwest, pests such as the silverleaf whitefly have been among the most damaging to agriculture.

Adult whiteflies hide and feed on the undersides of leaves. They are most noticeable when you rustle the leaves and a cloud of tiny white specks emerges into the air like "plant dandruff," as some gardeners aptly describe them.

Like aphids, whiteflies reproduce quickly, laying white eggs that hatch into white crawlers on the undersides of leaves. Whiteflies thrive in sunny, warm conditions. The crawlers and adult flies suck plant juices, weakening the plants.

Aphid and whitefly controls. The first line of defense is prevention. Check plants regularly. Avoid high-nitrogen fertilizers, which create young, succulent growth which these insects love. Isolate infested plants from others and control the pests aggressively.

For whiteflies, hang yellow traps coated with a sticky substance close to the tops of plants. Whiteflies are attracted to the color yellow, and once they land will be stuck and die. Hand-crush small populations of young aphids and whiteflies. Encourage natural enemies in the garden, such as ladybugs and lacewings, by planting diversity of plants and not spraying pesticides. As a last resort, use low-toxic sprays such as insecticidal soap, horticultural oil, and neem to reduce populations before they get out of hand. Repeat treatments every few days until the problem is under control.

Tips

Aphids can easily be removed from a plant by knocking them off with a stream of water from a hose. Once off, they tend not to climb back up.

To control small populations of whiteflies on houseplants, approach them in early morning and evening when they are most sluggish. Use a vacuum cleaner set on low suction to remove the whiteflies.

Photography by Suzanne DeJohn/National Gardening Association.

Avoiding and Solving Common Bulb Problems
National Gardening Association Editors

Follow these steps to prevent problems in your bulb patch.

• Check bulbs before buying or planting: Make sure they're firm and free of corky lesions, mold, and soft spots. Plant in well-drained soil.
• Plant in soil where disease hasn't been a problem.
• Provide at least half a day of sun. Full sun is best in cool climates, but midday and afternoon shade are needed in hot climates.
• Protect from pest animals.
• Plant at correct depth.
• Plant at correct time.
• Mulch at proper time.
• Buy the right varieties for your area's USDA Climate Zone.
• Water after planting to jump-start root growth.
• Fertilize at planting and during spring growth period.

Tools and Materials

The table below lists seven of the most common problems associated with crocus, daffodil, hyacinth, and tulip bulbs, see text below for recommended solutions.

Bulbs, leaves, blossoms eaten. Plant daffodils instead; they are unpalatable to animals. To deter smaller animals, use commercial or homemade repellents or scare tactics (dog or cat hair spread around bulb bed; hot pepper spray, flash tape or aluminum pie tins on twine, plastic scare owls or hawks). If deer are the problem, try a commercial deer repellent, or grow bulbs under protective netting supported by metal hoops or a wooden frame.

Bulbs are being dug up. Squirrels and chipmunks love to feast on crocus and tulip bulbs. Skunks dig in search of insects and worms but may also be attracted to organic fertilizers such as bone-, fish, or peanut meal. After planting, place hardware cloth, chicken wire, or other protective barrier over soil, and secure it in place. If skunks, cats, and dogs are troublesome, use well-decomposed organic amendments when planting.

Bulbs seem to disappear from the ground. If animals are the culprit, plant daffodils, which animals find inedible. To prevent pest animals from damaging bulbs, plant in an underground chicken wire cage. You can fashion your own, or purchase them ready made. Dry soil hinders root growth, causing bulbs to die and decompose instead of growing. Water well after planting, and roots should begin growing.

Growth starts even though cold winter weather is still expected. If bulbs haven't blossomed, they should weather the winter fine. Any blossoms and buds that emerge may suffer cold damage. Next fall, mulch the bulb bed just after the ground freezes in cool climates, and as temperatures reach winter time levels in warm climates.

Leaves appear, but plants don't bloom. In warm climates, choose varieties with low chilling requirements, and chill bulbs before planting. Allow leaves to remain in place until they fade completely. To hide fading foliage, plant companion annuals. If you aren't sure of a variety's longevity, ask the supplier before buying.

To improve soil fertility, fertilize at planting time. Each year in spring when plants are growing, spread an inch of compost, or feed with a low-nitrogen bulb fertilizer according to package directions. Bulbs need at least half a day of sun while the leaves are green (however, in warmest climates, afternoon shade is recommended).

Blossom stalks are short. Plant bulbs in the coolest area of your garden. In cool climates, mulch after ground freezes. In warm climates, plant low-chill varieties and mulch when winter temperatures are reached.

Tips

If bulbs have become crowded and are competing, dig and divide them. Reduce competition from surrounding plants by weeding and mowing regularly.

To increase soil fertility, in spring when plants are growing, spread an inch of compost or feed with a low-nitrogen bulb fertilizer according to package directions.

If shade has increased, thin tree branches or surrounding plants to allow at least half a day of sun in spring while the bulb leaves are green (in warmest climates, afternoon shade is recommended).

Lawn Problems
National Gardening Association Editors

Something wrong out there on the lawn? Time to do some trouble-shooting.

Rounding up the usual suspects will narrow the field of causes down to:

• Not enough water? This one's most likely, for sure, especially in the West.
• Wrong grass for the site? Maybe.
• Insects? Possible, especially midsummer.
• Diseases? Possible, especially a few weeks after a heavy fertilizing.

A lawn that is watered deeply, properly fertilized, and mowed a little on the long side will be able to fend off much common adversity.

Poor maintenance is responsible for thatch (too much nitrogen fertilizer, shallow watering) and stress caused by poor mowing practices or inadequate watering. Rake thatch out with a hand or power rake. Compacted soil may be responsible for poor water and fertilizer penetration, resulting in thin and uneven lawns. Aerators can be rented for do-it-yourselfers or the task can be contracted to a landscaper.

One common problem is having the wrong grass for the site, such as a Kentucky bluegrass in Phoenix, or Bermuda grass in deep shade. Overseeding bluegrass with more heat-tolerant tall fescue or replacing Bermuda grass with St. Augustine grass or zoysiagrass are the solutions.

With a couple of exceptions, insect infestations rarely demolish a lawn. Some exceptions are sod webworms, grubs, and chinch bugs.

Sod webworm damage shows up in late spring as small dead patches in an otherwise healthy lawn. They chew off the blades of grass near ground level. Check at night for a light brown caterpillar about an inch long. Bt is a remedy.

Grubs are larvae of beetles. When they have done their damage you can roll entire patches of lawn back like a carpet. One sign of grubs in a lawn is the presence of a lot of one-inch holes in the lawn where birds, skunks, or raccoons have been digging for a meal of grubs. Some grubs emerge from the soil as Japanese beetles, which attack gardens. Milky spore or beneficial nematodes are the remedy.

Chinch bugs are fond of St. Augustine grass, but will attack bluegrass and bentgrasses, too. Damage shows up as large, distinct patches.

A good remedy for solving insect problems is to collect a few in a bottle (you may need to go out with a magnifying glass, or at night) and take them to the cooperative extension service at your state university or to a garden center for identification. Learn all your options. Organic treatments are available for almost every problem.

Most lawn diseases shown up during periods of warm and moist weather. In the North, snow mold causes tan or gray patches to show up early in spring under snowbanks that are slow to melt.

While insect damage often shows up as foliage that is chewed, lawn diseases are usually a form of fungus that shows up as gray, tan, brown, or black spots or damage on the blades. Poor fertilization, mowing, and watering practices contribute to some diseases.

They can be difficult to identify specifically, so it may be necessary to take a sample to your garden center to determine a course of action.

Photography by Susanne DeJohn/National Gardening Association.