OBJECTIVES The student will be able to List

OBJECTIVES The student will be able to… • List the main disease problem of cacti and succulents and how to prevent it. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

OBJECTIVES The student will be able to… • Identify spider mite damage. • Identify mealybugs and scale insects. • Specify the treatments effective against root mealybugs, gnats, and springtails. • Identify powdery/downy mildew on a plant. • List the main disease problem of cacti and succulents and how to prevent it. • Explain how an insecticidal implant is used and for which pests. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

OBJECTIVES The student will be able to… • Define what a “low-risk” pesticide is. • Outline safety precautions when using pesticides on indoor plants. • Explain the most practical uses of biological control of house plants. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

OBJECTIVES The student will be able to… • Given a room in which plants will be grown, give a listing of ten indoor species and where they could be positioned relative to the windows to receive the correct amount of light. • Given a similar room, suggest three ways that the natural light in the room could be maximized. • Draw the spectrum of visible light and indicate the principal wavelengths of importance in plant growth. • List two symptoms of excess light in plants and two symptoms of insufficient light. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS • Indoor plant problems are almost always attributable to the environment, or the organisms contained in it. – Those caused by improper environmental conditions (light, water, temperature, and the like) are called cultural problems or physiological diseases. • Organisms harmful to plants can be anything from microscopic viruses to snails. – All are detrimental to plant health, whether by eating foliage, sucking sap, or causing spots on leaves. – Insects and also insectlike pests feed on houseplants. • Insects, which are six-legged, can be controlled by insecticides. • Pests such as mites, nematodes, and sowbugs belong to other classifications and may require different chemicals for control. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS • Control of insects, mites & diseases is best accomplished utilizing an approach called integrated pest management (IPM). • The easiest pests to detect are often those that damage the aboveground portions of plants—the leaves, stems, buds, and so on. – Collectively can be called foliage pests, some are encountered more frequently than others. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Mites • Mites have eight, rather than six legs & are related to spiders; hence the name spider mite. – Spider mites, red spider mites, cyclamen mites, etc. Mites—about the size of dust specks—are almost invisible to the naked eye. Several kinds of mites attack indoor plants. Figure 18 -1 Spider mite damage on a palm leaf. Close-up of a red spider mite. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Mealybugs • Mealybugs appear like specks of cotton, and all the many types—citrus, long-tailed, Mexican — are destructive pests. – Stunting, leaf drop, and, eventually, the death of a plant. The adult insects are pink and shaped like sowbugs. They appear white because of the white waxy fibers they secrete and in which they lay their eggs. Figure 18 -2 Mealybug, shown here with ants that can carry the pests among plants. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. They are very slow moving and frequently found in the axils of leaves or on the undersides along the veins. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Scales • Scale Insects (hard scale, soft scale) are relatively immobile & frequently not recognized as insects. – The type protective covering scales secrete determines whether they are called armored or soft scales. Armored scales are most common on indoor plants. They are covered with hard, blisterlike coats, ranging up to 1/8” diameter. Color can be clear to white, yellow, or brown, depending on the species, age & sex of the insects. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Figure 18 -3 Scale insects. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Scales • Soft scales secrete a soft waxy covering attached to their bodies, are nearly round in shape & generally larger than armored scales. – Soft scales also secrete sticky honeydew, which may draw ants, and provides a substrate on which sooty mold grows. • Sooty mold is black & does not directly harm plants —but is unsightly and decreases photosynthesis. – Presence of ants an sooty mold is often the first clue that scales are present. • Scales do their damage by puncturing plant tissues and extracting sap through needlelike mouthparts. – Plants become weakened, parts, or the whole plant die. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Whiteflies • Whiteflies resemble tiny moths, and cluster on the undersides of leaves, flying up when disturbed and resettling almost immediately. Damage is done by piercing the undersides of leaves to extract plant sap, causing paleness, spotting & weakening. Whiteflies also secrete a syrupy substance called honeydew and transmit viral diseases. Figure 18 -4 Whiteflies, approx. four times normal size. USDA. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Aphids • Aphids (plant lice or green flies) are soft-bodied insects, easily visible about 1/32” across. – Green, red, black, or any other number of colors, and cluster in large numbers on youngest leaves and buds. Aphids suck plant juices, causing deformed young leaves, secrete honeydew, making leaves sticky, and promote sooty black mold Aphids also transmit viral diseases Unlike other insects, young aphids are born live instead of hatching from eggs, and are easily killed with soap and oil sprays during any stage in their life cycle. Figure 18 -5 Aphids. USDA. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Thrips • Thrips are just slightly larger than spider mites, are winged in the adult stage, wingless when immature. – Foliage damaged by their feeding is silvery-colored, later turning brown. • Flowers they attack become streaked & buds fail to open. Figure 18 -6 Thrip damage on Ardisia. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. If thrips are suspected, the damaged plant part should be tapped over a white sheet of paper. This will dislodge thrips, which then can be seen briefly before they crawl away. Thrips are very difficult to see on plants, as they are extremely small and move fast © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Foliage Pests - Slugs and Snails • Slugs and Snails invade from outdoors, often entering the house hidden in the drainage holes of pots. – They chew large irregular holes, primarily at night, and hide during the day. • The best control is to pick them off. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Root and Media Pests Gnats—fungus gnats, manure flies, shore flies, mushroom flies—flying gnats, and their immature maggot stages are annoying to people and harmful to indoor plants. Overly wet potting media rich in organic matter provide ideal breeding areas, and a few gnats can multiply to several hundred in a short time. Figure 18 -7 The larva of a fungus gnat (about twenty times normal size. ) tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. They are usually seen crawling along the soil surface, where they lay eggs that hatch into tiny white maggots. Burrowing and feeding of the maggots on plant roots cause stunting and root diseases. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Root and Media Pests • Springtails derive their name from sudden jumping motion they display when they are disturbed. – Theyspend their entire life cycle in the soil, growing to about 1/16”, and eat only dead vegetation, causing no harm to indoor plants. • Nematodes (eelworms) microscopic worms that live in the medium and feed on the roots of plants. – Certain species live on plant leaves, entering stomates to feed, but they are rare on indoor plants. • Other species are predatory on fellow nematodes. – Different species of nematodes inflict different types of damage, primarily to roots. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Root and Media Pests • Root mealybugs are root-parasitizing insects that look like regular mealybugs but are smaller. – Because their feeding weakens plants, they should be controlled with an insecticidal soil drench. Figure 18 -8 Root mealybug. Calif. Dept. Food & Agriculture. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Root and Media Pests • Sowbugs (pillbugs) are small pests—not insects— but are related to the armor-covered crayfish. – They live only in damp places and will often be found hiding under pots or living inside the drainage hole. • Although they eat mainly dead organic matter, they also feed on roots and small seedlings and should be picked off and discarded. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

INDOOR PLANT INSECTS AND RELATED PESTS Root and Media Pests • Earthworms do not eat live plants and seldom are seen at the surface. – During their burrowing they digest potting medium and excrete it behind, leaving a network of tunnels. • Unless present in large numbers, they do no damage. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

ORGANISMS CAUSING DISEASE IN PLANTS Fungi • Fungi (molds) are microscopic organisms that absorb nutrition from dead or living organisms Fungi that cause diseases in plants are parasitic, invading the individual cells of plants and extracting nutrition. Fungi that attack indoor plants usually infect the roots; foliar fungi -caused diseases are less common. Figure 18 -9 Fungus spores germinating and invading a leaf through stomata. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Treatment is through modifying environmental conditions (moisture in particular) and chemical fungicides. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

ORGANISMS CAUSING DISEASE IN PLANTS Bacteria • Bacteria are single-celled plants also incapable of manufacturing their food. – Some use living plant cells for nourishment & reproduce rapidly by division under proper environmental conditions. • A few bacteria attack indoor plants, causing such disorders as leaf spots and root rots. – Partially controlled by copper or antibiotic sprays. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

ORGANISMS CAUSING DISEASE IN PLANTS Viruses and Viruslike Organisms • Submicroscopic viruses and viruslike organisms are encountered only occasionally in indoor plants. – When found, it can generally be assumed they were present in the plant at the time it was purchased. • Viruses/mycoplasmas are often transmitted among plants through mouthparts of contaminated insects – Especially whiteflies, aphids, and thrips. – Contaminated tools such as pruners can also pass the organisms from plant to plant. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Root Rot • Root rot is a general term for both fungal & bacterial diseases that cause the decay of root tissues. – Associated with poor growing conditions, such as medium that excludes air or lacks an outlet for excess water. • In extreme cases, permanent wilting occurs, and plants die. • Rot-infected roots are brown rather than white. – Treatment consists of chemical soil drenches, combined with improvements in culture. – Repotting in a better-drained medium in a pot bearing a drain hole and less frequent watering are recommended. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Crown or Stem Rot • Crown rot or stem rot attacks the stem or crown of a plant at the point where it enters the medium. Numerous bacteria & fungi found in unsterilized potting media often cause the disease; the organisms may also be airborne. The main symptom of crown rot is brown discoloration of the stem. Rotting prevents water passage up through the plant, and it can wilt and break off at the weakened area. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Figure 18 -10 Crown rot on a nerve plant (Fittonia argyroneura). Photo by Kirk Zirion. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Crown or Stem Rot • Cacti show a form of stem rot called dry rot, which causes the stem to discolor to yellow or brown and become sunken. The end effect on the plant is the same as stem and crown rot. Once infected, there is little to be done to cure a plant of the disease. Recommended procedure is to take cuttings of the uninfected portions & root in sterile medium for new plants. For cacti, the entire top of the cactus is cut off above the rot area and rerooted. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Figure 18 -11 Dry rot of cactus. Photo courtesy Andrew Schweitzer. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Mildew • Mildew is a foliar fungus disease that attacks a limited number of susceptible indoor plants. See the entire table on textbook page 344 - 345. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Mildew • The first symptom of mildew is a gray powdery residue on the leaves, which later turn yellow & drop, and the plant eventually dies. – Mildew is controlled by reducing humidity and applying a fungicide spray. After treatment, keeping the humidity low and all water off the foliage will prevent further problems. Figure 18 -12 The fungus disease mildew. Photo courtesy Marge Coon. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Leaf Spots • A number of bacteria and fungi occasionally cause leaf-spot diseases on foliage plants grown indoors. Figure 18 -13 A fungal leaf spot disease on German ivy (Senecio mikanioides). tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Symptoms vary with the disease & host—in general, pinpoint-sized spots will appear, enlarging and spreading slowly from leaf to leaf. The spots usually show a pattern like a center black spot surrounded by yellow or an irregular yellow spot ringed in brown. Fungicidal sprays may prevent spread, but there is often no cure. Remove infected leaves as detected and keep leaves dry to slow or stop the spread. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SPECIFIC DISEASES OF INDOOR PLANTS Viral and Mycoplasma Infections • Symptoms of a virus infection range widely, depending on the specific virus and its host plant. – Often include yellowing, curled foliage, spots, and stunting. – Although viruses are unlikely to spread among different species of indoor plants, they do occasionally. • No cures are known, and diseased plants should be discarded. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE PREVENTION Potting Medium • Prevention is better than any cure, and involves avoidance of both initial contact with the insect or disease, and its spread. – Potting media for indoor plants should be sterilized prior to use to prevent spread of fungi, bacteria, and soil pests. – Medium should be composed of ingredients in proper proportions, to ensure it drains quickly & thoroughly. • Provide a drainage hole or other escape for excess water. – Medium should contain adequate nutrients. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE PREVENTION Humidity/Water • Humid conditions optimal for most indoor tropicals can be both desirable & undesirable. – From the standpoint of pest and disease control. • Raising the humidity & misting can be used to slow spider mite breeding, and control their damage. – Humidity can increase a foliar fungus problem, as the spores of the fungus require high humidity to germinate. • Stagnant water, whether in the medium or on the crown, is detrimental to plant health. – Crown rot has been attributed to standing water. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE PREVENTION Humidity/Water • Overall, unless a plant is commonly susceptible to leaf spots or mildew and has been attacked previously high humidity is advisable. • Although misting foliage and showering are recommended on most plants, they should be avoided under certain circumstances. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE PREVENTION Isolation and Inspection • Isolation of newly acquired plants and older ones showing symptoms is a standard practice for controlling both diseases and insects. – Isolation outdoors or in a separate room is preferred, because air currents carry disease spores and insects readily. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Biological Control • Biological control is use of beneficial organisms that feed on, compete with, or infect pests. – These organisms are not available readily and must generally be ordered through the Internet. • Since these controls are living organisms, their use is somewhat more complex than use of pesticides, – They can only be used when residues toxic to them are not present on the plants. • A transition period between conventional pesticide use and biological control is usually necessary. – During this period, only pesticides that don’t leave toxic residues can be used. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Biological Control • Biological controls used commercially: – Steinernema feltiae nematodes for soil pest control. • Fungus gnats, shore flies, and other soil-inhabiting insects. – Whiteflies can be controlled by the whitefly parasites Encarsia formosa and Eretmocerus californicus. – Mealybugs are controlled by parasite Leptomastix dactylopii. – For two-spotted mites, Phytoseiulus persimilis mites released onto plants will provide effective control. – A product containing spores of a fungus Beauveria bassiana, which germinate when they contact the insects & invade the body, killing the insect. • Most effective under high relative humidity. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Home Remedies • Home remedies, used with persistence, can be effective, and many are completely safe to humans and avoid danger of accidental pesticide poisoning. – Wiping/washing with soapy water is a home remedy useful for reducing populations of mites or aphids. – Hand picking of large insects like sowbugs, scales, and mealybugs is another home remedy. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Home Remedies • Toothpicks or cotton swabs dipped in rubbing alcohol and touched to the insects can be used. When larger numbers of insects are present, many indoor plants can be sprayed with a 70% solution of rubbing alcohol. This spray may damage some plants; it should be tested first. The key to success with these methods lies in repetition. Probably not all of the pests will be killed, but the population will be reduced. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. Figure 18 -14 Touching mealybugs or aphids with a cotton swab dipped in alcohol is a reliable control method for small infestations. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • All chemicals can be dangerous to the health of people, pets, and plants if not used in accordance with package directions and in observance of safety rules. – Plant-derived insecticides should not be considered safer than synthesized ones. • The term pesticide actually includes all chemicals used to kill organisms that adversely affect the growth of plants – Fungicides, bactericides, insecticides, miticides, nematicides, and herbicides. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • Insecticides are broken down by source of the active ingredient — the chemical in the product that actually kills the pest. – As opposed to the materials used to dilute, chemically “carry, ” or scent it. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • Organic or Botanical Pesticides are derived from materials that occur in nature, primarily plants. – Pyrethrin is a nerve poison, marketed in 1947, on which a number of laboratory synthesized pyrethroids are based. • Resmethrin, cyfluthrin, sumithrin, tetramethrin, and bifenthrin are examples of pyrethroids. – Rotenone was used in 1848 to kill caterpillars, but was used in South America as a fish poison before that time. • It paralyzed the fish, causing them to float to the top where they could be gathered. – Neem products are insect growth regulators and are derived from the neem tree. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • Insecticidal soaps kill insects and insectlike pests such as mites by disrupting cell & tissue structures by the action of potassium salts of fatty acids. – They are of very low toxicity to humans. • Refined vegetable/mineral oils kill insects by smothering them & are safe for most indoor plants. – Used in conjunction with sulfur sprays, they may damage ferns and some other plants (phytotoxicity. ) tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • Synthetic Pesticides are those that are synthesized in a lab and, therefore, are not extracted from plants. – They may be more or less toxic than plant-derived products. • When pesticides are used indoors there is a high likelihood that people will come in contact with them. – Due to lack of ultraviolet light, they will often decompose more slowly than similar pesticides used outdoors. • Spraying must be done with care to minimize airborne droplets that can circulate in the air for extended periods of time in the limited ventilation found indoors. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • When a synthetic pesticide is used, a systemic applied to the soil is often useful for eliminating sucking insects and thrips. – Imidacloprid is available under several trade names and can be effective for up to 70 days. – Disulfoton is available for homeowners in one granular formulation only. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Commercial Pesticides • The only orthene formulation that can be used indoors is Acecaps, which are implants placed in holes drilled into the bark of large interior trees. Figure 18 -15 A medication-containing implant in place in a tree trunk. Shawn Nick photo. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

PEST AND DISEASE CONTROL METHODS Low-Risk Pesticides • Low-risk pesticides are designated as being less toxic to people & environment than other pesticides used for the same purpose. – EPA incentives have helped their development in recent years, especially for use on ornamentals. – Many of these chemicals are insect growth regulators that interfere with molting or reproduction. – When registered & available for a particular use, a good choice for use both by homeowners and by commercial horticulturists as well. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SAFETY PRECAUTIONS FOR USING PESTICIDES Personal Safety • Sprays are common for foliage insects, mites & diseases, drenches are used for soil insects, nematodes, and root diseases. – For personal safety, avoid contact with the pesticide. – Particular care should be taken when applying aerosol pesticides, and apply outdoors whenever practical. – During cold weather, an unoccupied room, that can be aired out afterward, can be used. – Washing equipment, and hands, with soap. – The plant should not be touched by people or animals. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SAFETY PRECAUTIONS FOR USING PESTICIDES Plant Safety and Pesticide Effectiveness • A stronger concentration than recommended may burn foliage severely, whereas a weaker one may fail to kill the pests. – Many species of indoor plants are easily injured by pesticides—review the pesticide label. • Test spraying several leaves is always advisable. • In application of water-diluted spray pesticides, “spray to runoff” is usually advised. – The chemical should be applied heavily enough to drip from the leaves. – Coverage should include all aboveground plant parts and the undersides of leaves, even those not presently infested. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

SAFETY PRECAUTIONS FOR USING PESTICIDES Plant Safety and Pesticide Effectiveness • Aerosol propellant used to carry the pesticide may be toxic, and the heat pulled from the leaves when the propellant vaporizes may cause cold injury. – Spray no closer than directions advise, at moderate distance, most propellant will vaporize, not reach the leaf. • Repeat sprays as recommended on package directions are the key to successfully controlling most indoor plant pests. – Many generations and life stages from egg to adult occur at one time, and not all will be chemically susceptible. – Repeat sprayings are necessary to do more than temporarily slow reproduction rates. tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458

END OF CHAPTER tab Practical Horticulture 7 th edition By Laura Williams Rice and Robert P. Rice, Jr. © 2011, 2006, 2003, 2000, 1997 Pearson Education, Inc. Pearson Prentice Hall - Upper Saddle River, NJ 07458