The best advice is to stay away from insecticides unless you see a problem. Pesticides that drip into our waterways cause fish kills and other environmental problems. I recommend that you use organic controls whenever you can. Insects build up resistance to pesticides, creating superbugs. Use the safest product possible and make sure you have the problem correctly identified so you will not use the wrong pesticide. Less usually is better than more. I have sprayed only twice on my property in the past 17 years for a localized problem.
Clearly many of the most frequently asked questions regarding insects revolve around tomatoes, those succulent orbs of earthy delight. As versatile as they are delicious, they can be grown in pots on a patio or planted in the yard. One bite will convince you that, whatever their problems, they are worth the effort. From letters and samples sent or presented to me at plant clinics, I present the condensed guide to growing tomatoes.
They can drive you buggy! A woman has a small Baggie in her hand. Inside is a branch from a tomato plant. The leaves are green but oddly puckered.
"What's wrong with my tomatoes?" she asks plaintively. The answer is aphids -small, soft-bodied insects that suck plant juices. The telltale sign is the twisted leaves. The remedy is a thorough spray with the garden hose or an application of insecticidal soap.
The next person carries the patient, or a small piece of it, in a plastic dish. Again, it's a tomato plant. Yellow leaves, with small dark splotches. Hmmm. Could be blight or maybe leaf spot. Both are treatable, if not curable, with a copper sulfate spray or a weak solution of hydrogen peroxide.
But it could also be fusarium or verticillium wilt, in which case the prognosis is poor. The gardener should have used a disease - resistant variety.
You have to face it. Pests are the order of the day with tomatoes. Expect leaf damage, but don't let it drive you crazy. Some insects, such as leafminer, will make the leaves look awful, but they will not affect fruit yields.
One of the reasons we grow our own food is to have some
control over what chemicals go on it. It's best to avoid heavy doses of
pesticides. Use commercial insecticidal sprays as a last resort.
Beneficial insects are a good first line of defense. Ladybugs control aphids, mealybug, scale and other sucking insects. Praying mantis control larger insects such as grasshoppers, beetles and other chewing pests. Parasitic wasps lay eggs on caterpillars, such as tomato hornworm and other larvae. Give the good guys a few days to start working on the bad guys before you panic. Now, let's get more specific.
Aphids come in many colors, from rosy pink to gray to pale green and they attack almost anything. Some have wings; others don't. If your plant is growing slowly, or if the leaves (especially the tender young ones) look twisted or puckery, check the underside for these little sap-sucking insects. Their sucking causes distorted foliage and poor growth. They may also spread tobacco mosaic virus, a disease fatal to tomatoes.
A strong spray of water will wash them off, but you will have to repeat the treatment often. You also can use a commercially prepared insecticidal soap, available at garden centers, to suffocate them. Or put a couple of tablespoons of hydrogen peroxide in a gallon of water and spray the plant regularly.
The good news? Aphids are a favorite food for ladybugs.
Stinkbug punctures the fruit and sucks out the juices. The fruit will change color where the stinkbug feeds and leaves a toxin behind; a tomato will turn white or yellow in the affected areas.
The best control is to remove weedy areas where they hide close to the tomatoes. If you continue to have problems, dust the fruit with diatomaceous earth or spray with insecticidal soap.
Tomato fruitworm is active in south Florida. The caterpillar is about an inch and a half long and can be green, pink or brown. It enters the tomato at the stem end and feeds on the fruit, making it worthless.
Nature can take care of these pests because they are often parasitized by trichiogamma wasps and tachnid flies. Or you can dust the fruit with diatomaceous earth or Dipel.
The tomato hornworm is a big guy _ more than 4 inches long- but its dark green color makes it difficult to see in foliage. It gets its name because of a horn at the rear end of its body. One or two of these fellas can eat an entire plant. Leaves may be chewed to the stem; occasionally fruit also will be consumed.
In most cases, they can be picked off by hand and dropped in a can of kerosene or ammonia. The best time to find them is at night using a flashlight, because they hide during the day.
One warning: If you find a hornworm or other caterpillar with small white sacks on its back, leave it alone. The sacks contain the larvae of a small wasp that preys on the hornworm and other caterpillars.
Blossom end rot
Blossom end rot is a common problem on tomatoes. One end of the fruit rots making it unuseable. A calcium deficiency is the cause of this disorder. Try spraying 2 times a week with 4 tablespoons of calicium chloride mixed in 3 gallons of water. Spray 1 quart per plant.
New Insect Pests –
Ficus benjamina has been under recent attack with the lac scale whose voracious feeding turns the ficus leaves black with sooty mold. A new thrip is now attacking Ficus benjamina. The thrip curls and distorts the leaves and the pest has been found in Dade and Broward counties so far. The damage is similiar in appearance to the thrip that has attacked Ficus retusa foliage for years. Ortho Systemic Insecticide and Bayers Tree and Shrub insecticide will control this pest. Gore Nurseries, Bob Betz told me about this new insect pest.
The gall or bud midge is a new pest attacking hibiscus blooms. The flower buds drop after this pest attacks. Thrips were the other pest attacking the buds causing bud drop. Ortho Systemic Insecticide will control this pest. Ortho Systemic Insecticide has a danger label so follow label directions exactly.
A biological control offers the best
long term cure but a soil drench of systemic Merit or Bayer's Lawn and
Garden Care will offer quick control. Follow label directions
exactly. Remember that systemic insecticides will also poison
the fruit so these products are not recommended for fruit trees.
rose had pale stippled foliage and I decided to see what the
problem was. The leaves on this otherwise healthy rose were
almost white in color.
More New Insect Pests added 1-08
More New Insect Pests Added 1-09
Laurel Wilt is a new disease threatening
avocado trees in South Florida. This disease was first noted in North
Florida where many native red bay trees were dying. The disease was just
discovered in South Florida at the University of Florida's Tropical Research
and Education Center in Homestead in Miami-Dade County. The county has
over 6500 acres in commercial avocado production and the crop is valued
at 40 million dollars by commercial growers in the area.
|HOW TO COMBAT
The most annoying part of growing vegetables is coping with
pests and diseases. Here are some tips on how to control them: If
an insect problem is not excessive, picking the pests off the leaves or
blasting them with water can be effective.
A. Look for new grasshoppers to hatch in March or April. They do not fly and can be killed in the early stages with an organic bait product (Grasshopper Attack, Grasshopper Control, Nolo Bait or Semaspore). The bait will also affect upcoming generations. Look for grasshoppers on spider and crinum lily and firebush particularly. An organic control for the very destructive lubber grasshopper is a mixture of hot pepper, soap and water sprayed on the leaves of the affected plants. This mixture will repel the grasshoppers. The big grasshoppers are best killed mechanically, as they become too large to be killed by commercial sprays. The large yellow lubbers do not fly like most of their relatives so are easier to catch and kill. They soon lay eggs and die off.
Q. My pinwheel jasmine and ponytail palms have black on their trunks and some leaves.
A. Your plants have sooty mold caused by sucking insects. Sucking insects like scale and whitefly create a honeydew secretion. The sooty mold grows on this and causes the blackened leaves. Organic gardeners can use Safer's Insecticidal Soap, but you must cover all affected areas with the soap, as it is a contact insecticide. You can also use Orthene to control. Retreat in 10 days.
Q. I have potted plants with ants in the soil. What can I do to get rid of them before bringing the plants inside?
A. Drench the pot with soapy water to drive the ants out. You may have to repeat the treatment several times.
Q. I have had a bad snail problem with my flowering plants. Do you have any organic controls? The bait is not very effective.
A. Many people report success by sinking saucers into the ground and filling them with beer. The snails and slugs drown in the beer; repeat the process until populations are reduced. Another trick is to surround the plants with diatomaceous earth or crushed shells from hard-boiled eggs. The eggshells and diatomaceous earth are sharp and puncture the snails/slugs so they dry out and die. The eggshells will need to be rinsed.
Q. What can do about black spot on my roses?
A. Funginex should control black spot. Keep foliage dry. Water in the morning only to minimize fungal problems. The roses should be in an open area, well spaced for maximum air circulation. Rake dead leaves from the ground around the plant to try to break the fungal space cycle. Orthenex is good if you want a combination of insecticide and funcigide.
Q. I have white fly on my poinsettia. What can I use to kill them?
A. The sweet potato whitefly has been attacking hibiscus and poinsettia. It is a very stubborn pest. Try a systemic insecticide like Orthene, which makes the whole plant poisonous. You will not have to worry about hitting every leaf as you do with a contact insecticide.
Q. I have a passion vine and hibiscus that produce buds, but the buds drop off.
A. You probably have thrips which damage new flowers, particularly roses, gardenias and hibiscus. They can be controlled with Orthene.
Q. Something is putting holes my fruit. What might it be?
A. The stinkbug often punctures fruit, particularly thin-skinned types of citrus. Small brown scavenger beetles will clean out the interior of the fruit after it has been punctured. Occasionally a fruit rat will eat fruit, but then the hole is much larger in the fruit. Stinkbugs are very mobile, so spraying is not effective. Pick fruit early, just at ripening, to beat this pest.
Q. My impatiens have deformed curled tips. They are in pots and in the ground. I have sprayed Orthene, Di-syston, Cygon, Diazinion, and other sprays and cleaned the pots with alcohol before planting. I have a super strain of whitefly. My potted hibiscus and mandevilla are affected. I have used Orthene, Cygon, Thiodan, and Di-syston. The Thiodan and ultrafine oil spray was effective but not for long. The yellow sticky traps worked but filled up very quickly. What do you suggest?
A. It sounds like you have used everything but the atomic bomb on your plants. Insects can become superbugs with repeated sprays of insecticides as they build up resistance. Your impatiens and mandevilla are high on my DO NOT plant list as they have lots of problems. Hibiscus also have problems but usually are more manageable. They are usually big growers to 10 feet plus and resent confinement in a pot for more than two years for the standard landscape varieties. I would plant them in the ground and use something like desert rose as a substitute. If you insist on fiddling around with these troublesome plants you might try a mix of Organocide and Excel which is an organic oil and pyrethrum mix. That should stop the whiteflies. Another option is to choose less troublesome plants for your yard. Wax begonia can substitute for the impatiens and is infinitely less troublesome. A good vine substitute could be Henderson's allamanda.
Q. How can I tell if my plant has spider mites? What do they look like? How did I get them? Do they fly or crawl and are they going to affect my outside plants? How do nurseries protect themselves?
A. Spider mites are microscopic sucking insects related to the spider. They crawl or can be transported by the wind. Spider mites can be detected if you shake some affected branches over a white paper. If little eight legged dots are moving around, you probably have spider mites. Verify with a magnifying glass. Heavy infestations sometimes can be detected because the plants have webbing over the needles and branches. Mites are most active in the winter months. They are already outside and since rainfall on the leaves washes them off, they are mainly a winter problem. Nurseries have overhead watering systems, so they don't have a major problem with spider mites. Take your plants outside, under a tree and blast off the mites with a strong jet of water from the hose. Other controls include Safer's Insecticidal Soap or a miticide such as Kelthane. To avoid problems in the dry season, hose your plants off periodically in the morning
Q. We have a millipede invasion on our screened porch every fall. What can we do for control?
A. Millipedes live in the grass and normally are not a problem. After a wet summer, they often seek higher ground to avoid overly wet soil. If you water a great deal, like once a day or every two days, you are drowning your plants and inviting millipedes. Get a rain sensor for your irrigation system so it will shut off automatically when it rains. If we have no rain, water no more than two times a week. Remember, interior areas get about 10-15 inches more rain than coastal areas. You may wish to spray a band of Dursban just outside the screened area to form a barrier against the invaders.
Q. What is the best way to get rid of nematodes?
A. Nematodes prefer sandy soils. Organic matter such as leaves, peat moss, etc. incorporated into the existing soil will discourage nematodes. Plantings of French marigolds also have a repelling effect if you turn them under the soil after blooming. Consider purchasing nematode-resistant plants to avoid the problem. Some varieties of plants are resistant to nematodes and many woody plants are grafted on resistant wood stock. In you are preparing new ground for planting and want to insure a nematode free area, solar sterilization of the garden plot over the summer is another possibility. Cover the garden tightly with clear plastic for two and a half months from the middle of June to the end of August. The soil will heat up to 130 _ 140 degrees, killing nematodes and other pests.
Q. How can I keep birds off my citrus trees?
A. The only way to keep birds off your citrus would be to invest in bird netting. Netting is used up north for cherry trees and blueberry plants. Park's Seed and other major mail order houses carry the netting. You might also try hanging a replica of an owl. That seems to discourage many birds. However, you need to move it occasionally or the birds get wise and return when they realize the owl isn't real. I've also seen strips of foil or shiny aluminum pie plates attached to the branches with bits with string, thereby allowing them to flutter in the breeze, used as an avian deterrent.
Q. How do I get rid of land crabs?
Land crabs are scavengers and are mainly above ground and active during the warmer months from May through October. They stay in their burrows in cooler weather. These burrows can be 15-20 feet long and reach down to the water table. Moth balls, poisoned bread and sonic systems have little effect on them. No pesticides are currently recommended for their control. They can be caught with crab nets and are edible. People in the Caribbean Islands consider them a delicacy. They keep the crabs captive for two weeks and feed them cornmeal to clean out their systems. It should be possible to control a good part of the local population or at least conjure up a good meal during a crab roundup on one of the full moon nights when they mate.
Q. We just put in pentas around our pool and they disappeared over night, thanks to a hungry iguana. What can I do to stop him without killing him?
A. Try using pepper spray, a homemade mix that will
discourage squirrels, rats, birds, insects and iguanas*. Add 2 teaspoons
liquid Ivory soap to a spray jar. Put a coffee filter or cheese cloth
over the jar mouth and add 2 tablespoons cayenne pepper and 1
tablespoon garlic powder. Add water and let the essence filter into the
jar, then spray the foliage. It will not harm the plant or the iguana
but it will taste terrible. When it rains the mixture will wash off.
. Our condominium is having a rat problem. Are there plants that attract rats?
A. A number of plants can attract rats and snakes as they provide good shelter. Pampas grass harbors these pests and the pandanus or screwpine with its stilt-like roots is also a likely candidate. The screw pine, Pandanus utilis, grows in a tree form and is less likely to encourage vermin as it is very open growing. The shrubby clumping pandanus types are more likely to provide shelter as they are very dense. Keep tree and palm branches pruned away from the building, porches, roofs and catwalks to help minimize rat problems.
White footed ants are a new pest in
Dursban, a chemical product, has recently been removed from the market and many homeowners are at a loss for what to do about insect control in their lawns.
Beneficial nematodes are an organic, living microscopic worm that preys on at least 24 lawn insect pests including sod webworm, army worm, chinch bug, lawn grubs and other lawn pests.
University of Texas conducted tests with beneficial nematodes and found that the beneficial nematodes killed 98% of fleas in the lawn. Most people spray for flea control and this is an effective product for that use.
It is important to note that the beneficial nematode containers are stale dated so must be applied before the stale date.
They can be applied directly to the lawn through a hose-on sprayer. Follow directions on the label. The nematodes are effective for six to seven weeks.
Sources for beneficial nematodes include: Gore Nursery, 1611 SW 19th Ave., Fort Lauderdale, 954-463-4673, Garden Gate Nursery at Sears, Corner of Copans and Federal Highway, Pompano, 954-783-1189. Mail order source: Gardens Alive, 5100 Schenley place, Lawrenceberg, Ind., 47205, 812-537-8651
Pruned and hatracked ficus may be subject to a relatively new disease. I first noted this disease, Hypoxylon canker, on a historic strangler fig in Palm Beach in 1999. We also noted the disease on Ficus retusa and Ficus benjamina. I recently saw the same disease in Plantation, Florida.
The disease usually enters the tree through large wounds caused by pruning. If your ficus is dying back this disease could be the cause. Look for discolored dark areas in the wound area. Bark peeling with dark areas underneath are also characteristic. No control is available to my
A new rust disease was recently found on Syzygium paniculatum, the Australian brush cherry which is commonly used for topiary work in this country. Roger Brook's of Four B's wholesale nursery first noted the disease on some of his topiaries. A & L Southern Agricultural Laboratories in Pompano Beach identified the rust disease and noted some commercial controls for the problem. The best option for people who buy topiaries is to specify Syzygium paniculatum 'Globulus' which is a slower growing, much darker green variety used in topiary work. The 'Globulus' variety is hard to propagate and tissue culture is the best option. Plants are more expensive, but are immune to the rust disease which defoliates the topiary.
Florida Dept. of
Agriculture & Consumer Services Memorandum states that Orange
New problems for the Sabal/Cabbage palm, our state tree