Making the Case for IPM

At the present time, there is a gap between the reality of integrated pest management and the acceptance of its application as a means of controlling pests. No one explanation can address the gap fully. It exists both within the green industry and within the client population. It is due, in part, to flawed employee training and to the consumer culture.

Better employee education and public education are needed now and in the immediate future to accomplish several things. First, both field technicians and clients must understand and accept the benefits of an IPM program over the familiar spray control programs. For some people, seeing predatory insects or decoy host plants as comparable to a chemical product is difficult. Not uncommon, they may express their reluctance to embrace IPM for their plants or their crops as they simul­taneously decry the overall evils of pesticide use nationally and inter­nationally. While the purchase and consumption of organically grown, pesticide-free fruits and vegetables has gained widespread acceptance, even panache, Americans have been conditioned to believe that beauty is the principle measure of worth of ornamental plants. They will not pay for blemished blossoms or spotted leaves. They want to play on golf courses with weed-free fairways and shop in climate controlled malls filled with perfect foliage plants. In a market-driven economy, it is not surprising that some growers and facility managers are hesitant to give their customers anything less.

Americans are also accustomed to rapid gratification of their needs. When people see insects chewing on their garden plants, they may not have the patience to wait for a biological control agent to reduce the population of chewers. However, with biological control measures, patience and perseverance are required.

Green industry companies must train their staff members to search for and recognize the predictable pests that affect their crops or other plants under their care. Employees must be trained to recognize the critical action thresholds of pest presence that trigger different control measures. Interior and exterior landscapers must be taught to under­stand how the thresholds and measures of control can vary, depending

on whether the plants affected are in high profile locations or are grow­ing in areas of lesser importance. In greenhouses, nurseries, and turf facilities, workers need a comparable understanding of the stages of development of pathogens and insects in order to time the application of control measures most effectively.

With consumers, education is equally vital. Customers cannot be expected to accept and pay for something they do not understand. A customer will understand receiving a bill for a landscape technician to spray the shrubs, but may not understand being billed for someone to scout the property for pests and decide that no control measures are warranted. Still other customers may have to be convinced that a low level population of some insects on their garden plants is no threat to the garden and can be kept at the low level with methods other than the blanket application of chemicals.

As public awareness and industry acceptance of IPM programs increase, it will become the expectation, not the exception throughout the green industry. Once every employee can become a knowledgeable spokesperson for environmentally sound pest control, then the industry and the nation will have taken a significant step toward safer and more natural techniques of pest control.

SUMMARY______________________________________

Biotic pests that injure plants include insects, fungi, bacteria, mollicutes, viruses, viroids, nematodes, foraging animals, and weeds. Animals usu­ally damage plants by feeding on their foliage or lower branches. Weeds compete with more desirable plants for space, sunlight, nutrients, and water. The remaining biological pests either infect or infest their host plants and live as parasites, deriving their sustenance from the cells of the host.

Insects are the most prolific and economically significant of all the infestious pests. They constitute over two-thirds of all the animal spe­cies on the earth. Grouped within the class Insecta, insects have a dis­tinctive external anatomy that separates them from other Arthropoda. Many of these features are important in their identification.

Reproduction in insects is usually sexual and requires mating between a male and female, although several species can reproduce through parthenogenesis. As young insects develop from egg to adult, they may change dramatically in their appearance. The change in form is termed metamorphosis and may include as many as four stages of development (egg, larva, pupa, and adult). The majority of insects are of greatest economic significance in their nonadult stages.

Disease in plants is caused by pathogens. The most important plant pathogens are the bacteria, fungi, viruses, and nematodes. Each group of pathogens has distinctive characteristics that separate it from the others, although the symptoms they create are often similar.

For disease to develop, the pathogen must be transferred to a susceptible host plant by an appropriate agent of dissemination. The pathogen must be in an infectious form (termed inoculum) and must arrive at an appropriate site of infection on the host. Environmental conditions favoring the pathogen’s development are also needed.

Following infection by a pathogen or infestation by insects the host may begin to exhibit symptoms of the injury. They can include:

• wilting

• color changes

• rotting

• death of tissue

• dwarfing

• increase in size

• tunneling

• holes

Weeds are plants that have no positive economic value and/or are growing where they are not desired. Their major damage is done as competitors with desired crop plants. In addition, weeds can serve as alternate hosts for overwintering insects or inoculum. Weeds are prolific seed producers. They include species that disseminate on every breeze and germinate quickly. Others remain dormant, distributed throughout a soil’s profile, awaiting their turn to be brought to the surface where they can germinate.

The purpose of pest control is to reduce the damage that can result from an injurious agent. Most growers seek a level of profitable control that allows the monetary return on a crop to exceed the cost of the con­trol measures. To determine the potential profitability of a control mea­sure, a grower must consider the value of a single crop plant, the ultimate value of the crop, and the average losses over a period of years.

Successful and profitable control of plant pests depends on the application of one or more of the four basic principles of control: exclusion, eradication, protection, and resistance. Chemical pesticides are one of the methods of applying the principles of control. They are available as fungicides, nematicides, insecticides, and herbicides and formulated as solutions, emulsifiable concentrates, wettable powders, granules, pellets, or fumigants. Each formulation is toxic and requires care in handling. Procedures vary with the formulations and specific products.

Integrated pest management incorporates biological control meth­ods and cultural manipulation to supplement pesticides in a multifac­eted approach to pest control.

Still to be surmounted is the gap that professional horticulturists and lay people have created between what they know and what they practice. Revised standards of quality and the immediacy of control are needed by everyone in order to return pest control to a safer and more natural state.

Подпись: A. SHORT ANSWER Answer each of the following questions as briefly as possible. 1. Assume that you are a grower of nursery and greenhouse stock, and your suppliers have the following problems with their propagative stock. Which ones could become a problem for you if you allowed their plants into your operation? a. fungal leafspot on roses b. weeds under the greenhouse bench c. whiteflies on mum cuttings d. galls on woody material e. soil-persistent fungi f. sun scald on tender cuttings g. rabbit damage h. nitrogen deficiency i. blight of flower buds j. spray injury to crop 2. Match the branches of science with their definitions Подпись: 3. Describe the insects using the following headings. a. phylum classification b. class name c. type of appendages d. body symmetry e. type and location of skeleton f. three body divisions g. number of legs h. number of pairs of wings i. number of antennae j. types of eyes k. location of the reproductive organs l. method of breathing 4. List the six most common insect mouthparts and at least one insect having each type. 5. List the four stages of complete metamorphosis in the order of their occurrence 6. Define the following terms common to incomplete metamorphosis. a. instar b. molting 7. In which stage of metamorphosis do insects usually do the greatest amount of economic damage? 8. Compare bacteria, fungi, nematodes, and viruses by placing Xs in the following chart to identify their characteristics.
Подпись: a. the study of plant 1. mycology plant disease diseases b. the study of 2. nematology viruses 3. entomology of c. the study of fungi viruses d. the study of 4. plant pathology insects 5. bacteriology of e. the study of fungi nematodes 6. virology f. the study of bacteria

ACHIEVEMENT REVIEW

Characteristic

Bacteria

Fungi

Nematodes

Viruses

Prokaryotes

Eukaryotes

Only single-celled in size

Multi-celled in size

Nonchlorophyllous

Reproduce only in a living host

Reproduce by cell division

Reproduce by sexual and asexual means

9. Complete the crossword puzzle using words related to the life cycle of fungi.

Making the Case for IPM

ACROSS

1. The vegetative body of a fungus.

3. The product of sexual fertilization.

5. The pairing of two compatible gametes that marks the start of the diploid phase.

6. Individual threadlike filaments that make up the mycelium.

7. A multicellular, filamentous thallus.

DOWN

2. The stage achieved by the fusion of two sexual nuclei.

4. The condition of the nucleus in the gametophytic stage.

8. Asexually produced spores.

10. Indicate whether each of the following is

a form of inoculum (A), a site of infection

(B), or an agent of dissemination (C).

a. animals f. wind

b. spores g. hyphal strands

c. wounds h. stomates

d. splashing water i. blossoms

e. bacterial ooze j. virus particles

11. Name the symptoms most likely to result

from the following situations.

a. Bacteria destroy the cells of the fruit of a flowering tree. Cellular fluids are released.

b. A localized swelling appears in the stem of a plant following invasion and egg laying by an insect.

c. A bench of plants in a greenhouse turn yellow despite the sunny weather.

d. The presence of bacteria near the crown of a tea rose causes the tissue to respond with hypertrophy and hyperplasia in a localized region.

e. The presence of a virus in a plant stimulates hypoplasia and hypotrophy in the tissue.

f. Leaf miners in a birch tree chew their way between the upper and lower epidermal tissue of the leaves.

g. Borers feed in the stem tissue of woody shrubs.

h. Insects feed on leaves in localized areas of leaf tissue.

i. Insects feed on the roots of a plant, creating a symptom like that created when pathogens plug a plant’s vascular system.

12. What is usually the final symptom of a symptom complex?

13. Define partial control, absolute control, and profitable control of plant pests.

14. Indicate which principle of pest control is being applied when the following measures are taken.

a. A grower plants only resistant varieties.

b. A sod farmer plants only certified seed.

c. Plants are not watered after 2 p. m. to allow them to dry off before evening.

d. Подпись: 15.Подпись:A landscaper hauls away all debris from a planting bed before winter sets in.

e. Quarantines are placed on all plant materials arriving from a country where infected plant material is common.

f. A diseased street tree is cut down and hauled away before the disease spreads to other trees nearby.

g. Growers fund research at a nearby university to speed development of a new resistant variety.

h. Healthy nursery plants are sprayed in the spring prior to onset of the rainy season.

i. Tulip bulbs, stored in a bag where diseased bulbs were found, are dusted before planted.

j. Hardwood cuttings taken from a tree in the woods are dipped in an antibiotic solution before placement into a pasteurized propagation medium.

Match the definitions with the pesticide or formulation they describe.

a. a chemical applied after the pest has arrived at the plant

b. a pesticide in the form of a poisonous gas that is most useful in enclosed areas

c. a pesticide whose active ingredients and carrier are in a homogeneous physical mixture

d. a pesticide applied to the host before the pest arrives

e. a pesticide that requires continuous agitation

to ensure uniform application

f. a chemical that kills some kinds of green plants and not others

g. a chemical that kills all green plants

h. pesticides formulated as coarse, solid particles

i. a pesticide applied by means of a water carrier despite its insolubility in water, using emulsifiers

16. List in order of increasing toxicity, the three signal words that indicate the toxicity of pesticide products. Place an A by each signal word that necessitates protective rubber boots and gloves. Place a B by each signal word that necessitates, in addition, rubber suit, hat, and mask.

17. Explain integrated pest management as an alterative to traditional chemical pesticide use.

B. MULTIPLE CHOICE

From the choices given, select the answer that best completes each of the following state­ments.

1. Insect legs are attached to the body part

known as the_____ .

a. head

b. thorax

c. abdomen

2. Insect wings are attached to the _____ .

a. head

b. thorax

c. abdomen

3. The type of legs, mouthpart, antennae, and wing venation pattern are important in of a particular insect.

a. control

b. reproduction

c. dissemination

d. identification

4. An insect digests food in the _____ .

a. fore-intestine

b. mid-intestine

c. hind-intestine

5. An insect’s nervous system is made up of

groups of cells termed______ .

a. spiracles

b. tracheae

c. ganglia

d. nerves

6. Female insects possess______ for laying

eggs.

a. an ovipositor

b. a clasper

c. a depositer

d. a spiracle

C. TRUE/FALSE

1. Indicate if the following statements are

true or false.

a. Weeds are parasites.

b. Weeds may serve as hosts for insects or pathogens.

c. Weeds can reduce the carbon dioxide content of greenhouses.

d. Weeds can reduce the heat efficiency of a greenhouse.

e. Weeds are visible problems only. They do not persist unseen in the soil.

f. Weeds do not have botanical names because they are not of economic importance.

g. All weeds are annuals.

h. Dormant weed seeds can persist in the soil for several years.

i. Uncultivated land is likely to have more weed seeds in the soil than cultivated land.

j. Weed seeds can pass through the digestive tract of animals.

k. The action threshold signaling the need for control is a common standard that can be applied to all crops and sites.

l. IPM scouting requires the immediate recognition of when the action threshold for a plant is near.

m. Alternate host plants can be used to attract insect pests away from economically prized plants.