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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
If you’re growing a Desert Rose (Adenium obesum), you probably know that it has an odd look, with a thick, succulent stem called a caudex that can become a bit grotesque as it enlarges. But its name comes from its desert-like native habitat and its colorful, showy flowers that resemble small roses. Usually easy to grow when given the right conditions, leaves on a Desert Rose might turn yellow and start to fall. This can stem from normal changes as it cycles through the year, or it might signal a problem that needs to be addressed.
A Natural Cycle A Desert Rose is sensitive to frost but can grow outdoors year-round in USDA hardiness zones 10a through 12. In colder regions, it also does well as a potted plant, either kept indoors as a year-round houseplant or grown outdoors in summer and overwintered indoors. Whether an outdoor plant in a warm-winter area or a houseplant, Desert Rose usually continues to grow throughout the year, so its leaves should stay green if it’s healthy and problem-free. But in cooler areas where night-time temperatures fall between 39 and 46 degrees Fahrenheit (4 and 8 degrees Celsius) and become 60 to 64 degrees Fahrenheit (15.5 to 18 degrees Celsius) during the day, a Desert Rose behaves like a deciduous plant, with its leaves gradually turning yellow and dropping. You can prevent a potted plant from losing leaves by moving it indoors before the air cools in the fall. If you grow the plant outdoors year-round and it becomes dormant in fall, it should put out new growth as soon as the air warms in the spring.
Possible Pests A Desert Rose might attract one of several pests that can affect its leaves, causing them to yellow and eventually dry up. These include mealybugs, fluffy white insects that feed on the foliage. If you see these insects, destroy each one by touching it with a cotton swab dipped in rubbing alcohol. Other possible pests include aphids — small greenish insects — and spider mites, which aren’t readily visible but make web-like coverings on leaves and buds. Both pests feed on plant juices and can cause leaves to yellow, wilt and fall off the plant. For a mild problem, use a strong jet of water to dislodge the pests. If the infestation is severe, spray the plant with insecticidal soap, diluted at a rate of 5 tablespoons per gallon of water. Repeat the spray every two weeks as needed.
Fungal Problems If a Desert Rose is grown in overly wet conditions, it might develop fungal stem rot, which usually starts at a stem tip and could also affect leaves on that stem, causing them to turn yellow, then brown. Eventually, the stem darkens or turns yellow and becomes soft, with the problem moving down the stem toward the soil. To save the plant, prune the affected part of the stem back, making the cut behind the soft area and into healthy, firm tissue. Disinfect the knife or shears by wiping the blade with rubbing alcohol between each cut to prevent spreading disease.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
Cacti and succulents have to be resilient to survive in some of the hottest and driest places on earth. Little gets past their sharp spines and tough skin, except two tiny insects that can do a lot of damage.
Mealybugs and scale are particularly attracted to cacti and succulents. They can injure and even kill them by feeding on their juice. Mealybugs attack all parts of a plant, above and below ground, but are usually found on leaves and stems. A plant will be covered with what looks like sticky white cotton, and up close, you can see small, white oval bugs. Mealybugs can be tough to completely eradicate. Scale insects cover themselves with hard oval, tan or brown shells. They congregate on leaves and stems, and multiply quickly.
Treat Cacti and Succulents for Mealybugs and Scale Wear gloves before handling cactus, or use bunched-up newspaper or paper towels to hold the plant. Spray water hard enough to dislodge the insects, but not so hard as to damage the plant. Nick scale off with a fingernail or tweezers.
Spray the plant with insecticidal soap, neem oil or horticultural oil. Follow directions on the package, as improper use can damage the plant. Wipe mealybugs or scale with a cotton swab dipped in a solution of 50 percent rubbing alcohol and 50 percent water. Large infestations may need treatment with a systemic insecticide. This is a last resort. Avoid insecticides containing imidacloprid, which can harm pollinators. Consider whether to remove and replace the plant instead.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
They live in the kitchen, crawling around and breeding on food, and then fly into hard-to-swat, in-your-face swarms when disturbed. If that behavior isn't a category winner, I don't want to see the competition!
Fruit fly (Drosophila melanogaster) invasions usually coincide with the ripening of summer fruit. Nothing draws a crowd of fruit flies like a bowl of peaches or tomatoes. So where exactly did they come from? Although it's tempting to think of these pests as alien invaders that hitchhiked from a distant land, it turns out they're natives. They usually live outdoors, though, and only come inside when they detect a potential breeding ground.
Fruit fly adults only live for a few days, so their need to breed is intense. Females lay up to 500 eggs on any fermenting food source, and that includes everything from ripe bananas to garbage disposal slime. Yuck! The presence of fruit flies is often the first tip that you've got a forgotten potato in the cupboard or that your toddler spilled apple juice under the table.
Despite the annoyance factor, fruit flies perform an important public service. Their larvae consume decaying matter that might otherwise turn into a source of fungal or bacterial infection or attract even more obnoxious pests, such as mice or rats. Females lay their eggs just under the surface of decaying fruit and other foods. After hatching, the grubs spend three or four days eating before they mature into breeding adults, and the cycle begins again. Their whole life cycle occurs in about eight days.
Controls and prevention Getting fruit flies out of the kitchen takes a bit of persistence, but it isn't difficult and doesn't require any pesticides. Eliminate or contain their food sources by refrigerating or covering ripening fruit, especially bananas, peaches and tomatoes. Cover your kitchen compost, using a container with a fitted lid. Search the cupboard for potatoes and onions that are starting to get soft and spoil. Mop up spills under the refrigerator
Rinse discarded and recyclable bottles and cans, especially beer and juice containers. Keep the garbage disposal clean.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
Despite its name, the pickleworm’s favorite meal is squash, both winter and summer types. These pinkish or green caterpillars feed on the blossoms, stems, and developing fruits of squash, cucumbers, cantaloupe and some pumpkins.
Pickleworms overwinter in tropical zones and as adult moths they migrate northward in early summer to lay their eggs on susceptible plants. Pickleworm larvae feed on flowers and tunnel into young fruits before pupating. With two to four generations per year, pickleworms are year-round pests in the southernmost part of the U.S. They can migrate as far north as the Carolinas during the summer.
Prevention and Control Plant as early as possible so crops are harvested before late summer, when damage is usually greatest. In southern areas of Florida and Texas, pull up and destroy vines and leftover fruits after harvest, along with nearby weeds, to minimize opportunities for the pest to overwinter.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
Large, ragged holes in the leaves of cabbage, broccoli, Brussels sprouts, collards, kale, or cauliflower plants are a sign that cabbageworms may have invaded your garden. The green caterpillars may also bore into the heads of these crops, leaving behind their dark green frass (droppings). Cabbage loopers cause similar damage. Plants can tolerate a moderate amount of damage without reduction in yield.
The cabbageworm is the larval form of a small white butterfly (Pieris rapae) that has three to four black spots on its wings. The butterfly lays white eggs on the underside of leaves; eggs hatch within a week and the larvae feed for approximately two weeks. The larvae pupate in silken cocoons attached to the lower leaves. There are several generations per year, and they are found throughout North America.
Prevention and control Cover susceptible crops with garden fabric in early spring as a barrier to the egg-laying moths. If plants are not covered, inspect them frequently. Crush the eggs; handpick the cabbageworms and drop them into a pail of soapy water. Encourage native beneficial insects, such as parasitic wasps, that prey on caterpillars. Remove plant debris from the garden in fall to minimize opportunities for the pest to overwinter.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
A major agricultural pest, the tomato fruitworm can feed on many different plants. Hence, the species has been given many different common names including cotton bollworm and corn earworm. It has also been known to consume tobacco, legumes, grain sorghum, and other vegetables and fruits.
The pest occurs throughout the Western Hemisphere. In warm areas several generations occur annually. North of Interstate 70 the pupae cannot overwinter in the soil. Most populations enter Missouri as migrating swarms of moths from the southern United States. Symptoms and Diagnosis Tomato Fruitworm The evidence of tomato fruitworm is usually a visible black hole at the base of the fruit stem. When the tomato is cut, tunneling is evident and the cavity may contain frass and decay as well as the worm itself.
Corn Earworm Most evidence of corn earworm is at the tip of the ear—damaged kernels, frass, the worm itself, and possibly resulting fungal disease. Life Cycle The eggs of this pest are each about ½ the diameter of a pinhead. They are spherical with a flattened base and white or cream in color, developing a reddish-brown band just prior to the young hatching. Depending on the temperature, the young hatch in 2-10 days.
The larvae measure 11/2-2 inches when fully grown and may be green, brown, pink, yellow, or even black. They have tan heads and alternating light and dark stripes run lengthwise on the bodies. The skin is coarse and has small, thorn-like projections called tubercles. The larval stage lasts 14-21 days. When the larvae are finished feeding the worms drop to the ground and enter the soil near the base of the plant where they transform into shiny brown pupae. During summer adults emerge in 10-14 days and start the cycle over. In the fall, south of Interstate 70 the pupae survive winter 2-6 inches below the soil surface. The moths emerge from overwintering pupae during late April and May.
Adult moths are usually light yellow-olive in color with a single dark spot near the center of each forewing. Each forewing has 3 slanted dark bands. Their hind wings are white. The cycle repeats itself with the moths laying eggs at dusk on host plants on warm days. The total generation time is 28-35 days. The moths lay eggs on the foliage of the tomato plants. With corn the moths usually lay eggs on corn tassels and silks but the larvae will migrate down the silk to the ear tips within one hour of hatching where they will feed on the developing kernels protected by the husk. When larval development is complete the larvae chew through the husk and drop to the ground to begin the pupal stage.
Integrated Pest Management Strategies Tomato Fruitworm 1. Sanitation. Collect and dispose of any infested fruit before the insect completes its life cycle. 2. Introduce parasitic wasps. Do not remove parasitized caterpillars. Instead, leave them to assist as a natural, biological control. 3. Dusting with diatomaceous earth may kill larvae. 4. Use of a biological pesticide such as Bt can kill larvae during the warmest months.
5. Use chemical pesticides. The pest has developed a resistance to many pesticides but the following pesticides are often used: esfenvalerate (Asana), methomyl (Lannate), azinphos-methyl (Guthion), carbaryl (Sevin), or pyrethrin. These must be applied before the worm enters the fruit. 6. Minimize local food sources. Avoid planting tomatoes near corn or other hosts of the fruitworm to minimize populations.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
The squash vine borer, Melittia cucurbitae, is native to Missouri. It is a serious pest of both summer and winter squash. The insect will also attack cucumbers, pumpkins, muskmelons, and watermelons.
Symptoms and Diagnosis The first symptom is generally wilting of part or all of the plant. At the base of the plant, moist, sawdustlike debris (frass) can be seen piled outside small holes in the stem. If the stem is split lengthwise, frass and one or more fat, white caterpillars with brown heads can be found tunneling in the stem.
Life Cycle Squash vine borers overwinter as pupae in a silken, dirt-covered cocoon one or two inches below the soil surface. Adult squash vine borers are day-flying clear wing moths a little over 1/2 inch long with reddish-white bodies and black bands on their abdomen. They have a distinctive wasp-like appearance. Their forewings are greenish-brown but their hind wings are transparent. The insect has a wing span of about 1-1/2 inches. The hind legs are orange and black, long, and hairy. Adults emerge in early to mid-June through July, first appearing about the time cucurbits begin to bloom, and lay 1/10 inch long, brown or reddish-brown eggs in rows or clusters on all parts of the plant but predominately on the stem. Upon hatching, the larvae immediately bore into the stems and remain there until full grown; then full-grown larvae move into the soil to overwinter. There is one generation a year.
Integrated Pest Management Strategies 1. Remove and destroy the borers. Once detected the borers need to be killed or removed from the stem. The easiest way is to slit the stem above where the hole and frass is noticed and remove the insect or insects from the stem. Cover the stem area with soil to encourage new roots to form above the damaged area. This may save the plant, depending upon the severity of the damage. Dip your knife in a 10% solution of bleach before making the next cut in order to prevent transmitting wilt or rot organisms, which might be present.
2. Biological control. Borers can also be killed by injecting a solution of Bacillus thuringiensis (Bt) into the infested stem, using a disposable syringe or wood working glue injector. Follow the disinfecting and mounding procedures discussed above. This method can also be used as a preventive if injected into the stem 1-1/2 inches above ground level when the plants first begin to flower. 3. Promote rooting along stems. About every five leaves or so, place a small mound of soil over the stem to encourage rooting. Then if borers kill the lower part of the plant, the upper parts will have roots to recover.
4. Clean up plant debris. Plants killed by borer activity should be pulled up. Place these plants in a large, clear, plastic bag and leave it in the sun for a week or so. This will kill any borers still in the debris. In the fall, clean up and dispose of old plant debris. Leave the soil uncovered for a day or so to give birds a chance to clean up any insects on the ground. 5. Protect plants with a row cover. In subsequent years, early in the season, plants can be protected with floating row covers secured on all edges to prevent flying adults from laying eggs on the plants. The cover needs to be removed when the plants begin flowering.
6. Use chemical controls with caution. Properly timed chemical pesticides can be effective. Scout plants early and often, watching for the first signs of borer’s frass at entrance holes in the stems indicating egg laying has occurred. Two insecticide applications spaced 5 to 7 days apart will control the majority of newly hatched larvae before they enter the vines. Chemical controls are not effective once the borer is inside the stem. Sevin can be applied to crowns and runners when the plants begin to vine. Apply late in the day because Sevin is very toxic to bees that frequent vine crops and facilitate pollination. Bees carry grains of Sevin dust back to the hive where it can kill many bees.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
Squash bugs, Anasa tristis, are sometimes mistakenly called stink bugs because they may give off a foul odor when squashed. Stink bugs have wider shieldshaped bodies than squash bugs. Squash bugs are pests on all cucurbits including cucumbers, muskmelons, pumpkins, squash, and watermelon. Squash and pumpkins are the most susceptible to squash bug attack.
Symptoms and Diagnosis Squash bugs destroy plant tissue by sucking out the sap from leaves and stems and depleting nutrients from the plant. This feeding causes leaves to wilt and dry out. They eventually turn black and fall off the vine. Adult pests can be seen feeding on main stems. Nymphs are more likely to be found feeding on the undersides of leaves.
Life Cycle Adult squash bugs are brown or black, flat-backed, and 1/2 to 3/4 inch long. In the spring when plants begin to develop runners, elliptical, yellow or brown eggs are laid in groups on the undersides of the leaves. Immature stages (nymphs) have gray-green bodies and red or black legs. Adults overwinter in garden debris and emerge the following spring. There is only one generation per year.
Integrated Pest Management Strategies 1. The key to management is early detection and control. There are two critical times when plants are most vulnerable to damage. First is when plants are seedlings with undeveloped root systems and vulnerable to damage from overwintering adults. The second critical time is as plants begin to flower and eggs first begin to hatch. Handpick bugs and eggs and destroy them by dropping them in a bucket of soapy water. Egg masses are either orange-yellow or bronze in color and can usually be found on the undersides of leaves.
2. Cover young plants with row covers of nylon netting or cheesecloth to deter bugs from feeding on them. 3. Plant resistant squash varieties like ‘Butternut’, ‘Royal Acorn’, ‘Sweet Cheese’, and ‘Black Zucchini’. 4. Do a thorough garden cleanup in the fall in order to remove overwintering sites. Tilling plants into the ground after the growing season helps to expose the overwintering stage of the squash bug and reduce their populations.
5. Use an insecticidal soap every 3 days for the first 2 weeks after squash bugs first emerge in the spring. Insecticidal soaps are contact insecticides, so take care to make sure that all plant surfaces are covered, especially the undersides. 6. Dust plants with permethrin or sabadilla.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
The presence of white butterflies fluttering around the garden signals the start of a possible infestation of imported cabbageworm. The adult cabbage butterfly, Pieris rapae, is white with black tips and one or two black spots on the forewings. The larva (the cabbageworm) is a bright green caterpillar clothed in fine, short hairs that give it a velvety appearance. The imported cabbageworm will attack all growth stages in cole crops.
Symptoms and Diagnosis When the adult butterflies are observed fluttering around the garden, the larvae and the damage they do will soon be obvious. All stages of growth in cole crops can be attacked by the larvae, but they are often observed on the underside of developing leaves. The outer leaves may become riddled with large ragged holes from the larvae's feeding. If leaves are parted, masses of greenish-brown excrement can be found at the base of the leaves. The larval feces often contaminate edible portions of the plant.
Life Cycle The imported cabbageworm overwinters as a pupa attached to plant debris. The adult butterfly emerges the following spring and flies about the garden area during daylight hours. The elongated, yellow, ribbed eggs (shaped somewhat like a football) are laid on the underside of the foliage. The eggs hatch in 7 days. The emerging caterpillars are velvety green. Theyfeed on all cole crops for about 15 days. After this, they pupate, and new adults emerge in about 10 days. There are 2 or 3 generations of imported cabbageworm each year.
Integrated Pest Management Strategies 1. Handpick the cabbageworms off of the underside of the leaves while plants are young. This procedure is effective when plants are young or if only a few larvae are present. 2. Use row covers. Position row covers or netting over plants to prevent egg laying by the butterflies. Start controls before the white cabbage butterflies are seen fluttering around the yard. 3. Fall sanitation. Clean up and remove infested plant material after harvest to eliminate overwintering sites of the pupae.
4. Use Btk spray or dust. Dust plants with Bacillus thuringiensis kurstaki (Btk). Begin treating the plants when white butterflies are first noticed and the cabbageworms are still small. It may take several days before the insects die after feeding on Btk, but feeding will usually stop shortly after the plants are treated. 5. Chemical controls. Spray with insecticidal soap, carbaryl (Sevin), malathion, cyfluthrin, or permethrin when plants and larvae are young and damage is increasing. The larvae are more easily killed when young and this will minimize the amount of insecticide needed for control. Carbaryl (Sevin), the active ingredient in Sevin, is very toxic to honey bees; do not use near flowering plants.
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Dummer. ゛☀
2017年09月19日
Dummer. ゛☀
The tomato hornworm, Manduca quinquemaculata, and the tobacco hornworm, M. sexta, are common pests of tomato, tobacco, eggplant, pepper, and potato throughout most of the United States. The hornworms are large (up to 4 inches long), bright green caterpillars with diagonal white stripes and a prominent horn at the rear. The two species have slightly different markings. The tomato hornworm has 8 diagonal white stripes on each side; the horn is straight and black. The tobacco hornworm has 7 diagonal white stripes; its horn is curved and red.
Symptoms and Diagnosis Larvae of both species consume entire leaves and small stems and may chew large pieces from green fruit. Hornworm damage is obvious when the infestation is moderate to heavy because of the large amount of defoliation. Search for the large caterpillars. Large, black droppings on the leaves or ground beneath the plant will usually indicate the presence of hornworms.
Life Cycle Hornworms overwinter in the soil as hard-shelled, brown pupae. Large adult moths, known as sphinx or hummingbird moths, emerge in May or June and deposit spherical green eggs on the undersides of leaves of host plants. The larvae hatch a week later and feed on foliage and fruit for three to four weeks until reaching full development. Pupation occurs in the soil and adults emerge 2 to 4 weeks later to lay second generation eggs. In Missouri there may be one or two generations depending on location.
Integrated Pest Management Strategies 1. Handpick caterpillars. Handpicking is usually all that is needed to control these pests in a home garden. Larvae are most easily located in early morning, often on the exterior of the plant. Leave any caterpillars with small white cocoons on their backs; they are being parasitized by a braconid wasp, which will soon produce more wasps to control them. 2. Biological control. Bacterial insecticides containing Bacillus thuringiensis kurstaki (Btk) are effective when larvae are smaller. It may take several days for the caterpillars to die, but feeding generally stops shortly after treatment.
3. Cultivation. Disking or rototilling after harvest destroys pupae in soil, reducing overwintering numbers. 4. Chemical control. An application of carbaryl (Sevin) or permethrin will effectively control hornworms if handpicking is impractical. However, chemical control will also reduce the numbers of beneficial insects.
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