integrated pest management ipm in greenhouses and the home

1. Integrated Pest Management (IPM) in Greenhouses and the Home R. Bronson, Editor

2. IPM = Integrated Pest Management Integrated Pest Management (IPM) is the coordinated use of pest and environmental information with available pest control methods to prevent unacceptable levels of pest damage by the most economical means and with the least possible hazard to people, property, and the environment.

3. What IPM is NOT! IPM does NOT prohibit the use of pesticides! IPM is NOT merely a biological or �organic� pest control program IPM is a decision-making process, and NOT a stringent or rigid management regime

4. Components of an IPM Program Monitoring and Sampling (inspect carefully) Pest Identification (what is the pest?) Decision-making; IPM decisions are guided by �action thresholds� (what actions Follow-up (re-inspect) Record-keeping (write it down, history) Education (learn)

5. Greenhouse insects are difficult to manage because Up to 20 generations per year Have no natural enemies to reduce populations Almost unlimited food supply Environmental conditions are constant Some life stages are not susceptible to treatment Major insecticide and miticide resistance has developed.

7. Incomplete Metamorphosis Hatch from an egg Immature stage is a nymph Nymphs resemble adults All life stages have similar feeding habits and are pests

8. Complete Metamorphosis Four-stage life cycle Egg Larva Pupa Adult Larvae may have different feeding habits than adults and often cause the most damage

9. Piercing-Sucking Mouthparts Phloem feeders Incomplete metamorphosis Hemiptera Homoptera Thysanoptera

10. Monitoring and Sampling Thorough and consistent inspections (scouting) before pest(s) cause problems Sticky cards (aphids, whiteflies, fungus gnats, thrips, and shoreflies) Potato slices (fungus gnat larvae) Indicator plants (petunias or fava beans for thrips)

11. Sticky Cards Place sticky cards at a minimum rate of one card per 1000 square feet Space them equally in a grid pattern Place additional cards near entrances and vents to detect migration from the outside Check and change cards weekly. Stikem a special nonpoisonous pest glue for making your own sticky cards may be purchased online.

12. Colors found to be most useful for Sticky Cards BLUE Thrips (1-2 inches above crop canopy) YELLOW Aphids (vertical) Fungus gnats and shore flies (horizontal) Whiteflies (vertical)

13. Proper Pest Identification Accurate identification is essential! If you are not sure, ASK someone who does know (i.e., county agent, colleague, vendor, etc.) Otherwise the action (strategy) you select will likely be ineffective and you will have wasted your time and money.

14. Order Homoptera Aphids Mealybugs Scales Whiteflies Incomplete metamorphosis Sucking mouthparts Two pair of membranous wings Piercing/sucking mouthparts on both nymphs and adults Phloem feeders Paurometabolous � adults and nymphs look similar May transmit plant disease Damage appears as stunting, mottling, discoloration, & wiltingPiercing/sucking mouthparts on both nymphs and adults Phloem feeders Paurometabolous � adults and nymphs look similar May transmit plant disease Damage appears as stunting, mottling, discoloration, & wilting

15. Aphid Life Cycle Females reproduce for 20-30 days giving birth to 60-100 live nymphs. Nymphs become reproductively mature within a week at greenhouse temperatures. Winged females are produced when food resources become scarce or an area becomes overcrowded. Males and eggs are only produced in response to colder temperatures and shortening day length. Aphids overwinter as eggs outdoors but can continue to produce year round in the greenhouse.Females reproduce for 20-30 days giving birth to 60-100 live nymphs. Nymphs become reproductively mature within a week at greenhouse temperatures. Winged females are produced when food resources become scarce or an area becomes overcrowded. Males and eggs are only produced in response to colder temperatures and shortening day length. Aphids overwinter as eggs outdoors but can continue to produce year round in the greenhouse.

16. Soft-bodied insects Wings present or absent Cornicles (tail pipes) Honeydew Sooty mold May transmit viruses Breed without mating-give birth to live young (5day generation time at 850f Reduces plant vigor, stunting, malformation Aphids Insert their mouthparts when they feed and remove plant sap. Chlorotic spots develop. Leaf distortion when aphids feed on buds.Insert their mouthparts when they feed and remove plant sap. Chlorotic spots develop. Leaf distortion when aphids feed on buds.

17. Intervention (Control Strategies) Biological Cultural (Mechanical/Physical) Chemical (Pesticides)

18. Biological Control = The use of any living agent to suppress pest populations Predators Parasitoids Bacteria Fungi Nematodes

19. Cultural Control = Inspect new plants thoroughly, reject or discard badly infested ones. Keep doors, screens, and ventilators in good repair with fine mesh screening. Use clean or sterile soils or media Eliminate pools of standing water and any insect breeding debris. Avoid over-watering and promote good ventilation

20. Chemical Control = The use of pesticides to reduce pest(s) to an acceptable or tolerable level. Insecticides (insects) Miticides (mites) Fungicides (mildew etc.) Rodenticides (rats, mice etc) Molluscicides (Slugs and snails) Total elimination is rarely possible.

21. Green Peach Aphid on Peppers

22. Honeydew

23. Honey Dew & Sooty Mold

24. Aphid Monitoring Check as many plants as possible Look at terminal buds and lower leaf surfaces Cast skins, honeydew, & sooty mold are indications of aphid infestation. Yellow sticky traps can monitor winged aphids

25. Aphid Parasitoid

26. Parasitized Aphids The aphids on the left were parasitized by a brachonid wasp. Trapdoor on the insects on the left was created by the adult wasp at emergence.The aphids on the left were parasitized by a brachonid wasp. Trapdoor on the insects on the left was created by the adult wasp at emergence.

27. Aphid IPM Sanitation Remove weeds inside and outside of greenhouse Screen vents and windows Limit the use of quick-release fertilizer Beneficial Insects Green lacewings Ladybeetles Parasitic wasps

28. Aphid Chemical Control Rotate chemicals every 2-3 applications to prevent insecticide resistance Organophosphate resistance common Marathon - drench better Endeavor - slow kill-but stop feeding fast Thiodan Orthene, Talstar, Azatin, Avid, Beauvaria

29. Mealybugs Small, oval insects covered with a white, cottony wax. Related to scales but retain their legs throughout their life cycle. Citrus mealybug is the most common and most damaging. Can infest all plant parts including roots. Small, oval insects covered with a white, cottony wax. Related to scales but retain their legs throughout their life cycle. Citrus mealybug is the most common and most damaging. Can infest all plant parts including roots.

30. Mealybug Life Cycle Mealybugs lay up to 600 small, yellow eggs in a protective cottony mass. Egg-laying is temperature-dependent with fewer eggs laid under high temperature conditions. Long-tailed mealybugs don�t lay eggs but bear live young in a fashion similar to aphids. After laying eggs over a period of 5-10 days, the female dies. Female mealybugs go through 3 instars and are mobile their entire lives. Male nymphs settle and spin a white, waxy cocoon. Adult males are tiny and winged. One generation takes 1-3 months.Mealybugs lay up to 600 small, yellow eggs in a protective cottony mass. Egg-laying is temperature-dependent with fewer eggs laid under high temperature conditions. Long-tailed mealybugs don�t lay eggs but bear live young in a fashion similar to aphids. After laying eggs over a period of 5-10 days, the female dies. Female mealybugs go through 3 instars and are mobile their entire lives. Male nymphs settle and spin a white, waxy cocoon. Adult males are tiny and winged. One generation takes 1-3 months.

31. Mealybug Damage Feed at stem tips and leaf junctures. Mostly on tropical foliage plants Stunting, yellowing, defoliation, wilting. Honeydew and sooty mold. Citrus mealybug can inject a toxin while feeding.

32. Mealybug Monitoring Visually inspect leaves and stems especially at leaf nodes and joints. Yellowed or wilted foliage may indicate underground infestation of African violets or other susceptible species. Unpot to inspect.

33. Mealybug Destroyer = Predator

34. Mealybug IPM Inspect plant material on arrival. Destroy heavily infested plants. Remove soil and compost piles from growing areas. Description: Bodies up to 1/4" long are covered with white powdery wax. Colonies look like small tufts of cotton along veins on underside of leaves and at base of leaf stems. They infest most houseplants, plus apple, grape, peach, pear trees. Infested fruits are disfigured and covered with dark mold. Mealybugs extract plant juices, causing dwarfing, wilting, and early fruit drop. On houseplants and flowers they cause color loss, wilting, and eventual death of affected parts. Solution: Oil-AwayTM Insecticidal Spray or Eco-OilTM Insecticidal Spray provides excellent control. Green Lacewings provide good control and are more effective at cooler temperatures than other mealybug predators. PyolaTM Insecticidal Spray is also useful. Mealybug Description: Bodies up to 1/4" long are covered with white powdery wax. Colonies look like small tufts of cotton along veins on underside of leaves and at base of leaf stems. They infest most houseplants, plus apple, grape, peach, pear trees. Infested fruits are disfigured and covered with dark mold. Mealybugs extract plant juices, causing dwarfing, wilting, and early fruit drop. On houseplants and flowers they cause color loss, wilting, and eventual death of affected parts.  Solution: Oil-AwayTM Insecticidal Spray or Eco-OilTM Insecticidal Spray provides excellent control. Green Lacewings provide good control and are more effective at cooler temperatures than other mealybug predators. PyolaTM Insecticidal Spray is also useful.Mealybug Description: Bodies up to 1/4" long are covered with white powdery wax. Colonies look like small tufts of cotton along veins on underside of leaves and at base of leaf stems. They infest most houseplants, plus apple, grape, peach, pear trees. Infested fruits are disfigured and covered with dark mold. Mealybugs extract plant juices, causing dwarfing, wilting, and early fruit drop. On houseplants and flowers they cause color loss, wilting, and eventual death of affected parts.

35. Mealybug Chemical Control Use insect growth regulators (IGR) when beneficial insects are present. Need 2-3 treatments at 10-14 days - eggs and adults are somewhat protected Orthene Marathon Insecticidial Soap Permethrin Scimitar Neem Oil Beauvaria

36. Scale Crawlers & Eggs

37. Hemispherical Scale

38. Oleander Scale

39. Scale Monitoring Visually inspect lower leaf surfaces and stems. Yellowed foliage or presence of honey dew on leaves may indicate a scale infestation. Foliage plant pest - wide host range including ferns.

40. Scale IPM Inspect new plant material on arrival Wash off honeydew and dislodge crawlers with water sprays Remove and destroy heavily infested plants.

41. Chemical Controls of Scale Spot treat if there are 2 or more adult scales or large numbers of crawlers per leaf. 2-3 treatments at 10 day intervals needed Insect growth regulators (azadirachtin) and soaps will control soft scales.

42. Order Thysanoptera aka Thrips

43. Thrips Damage Rasping mouthparts puncture plant surfaces. Egg-laying also damages plants. Injury appears in streaks and also as wet, varnish spots in feeding injury sitesPetals are distorted.. Blossoms become brown. Buds fail to open. Most of damage on flowers- and new growth Damagae also found on underside of leaves of foliage plants

44. Thrips Damage on Mum foliage

45. Thrips Feeding on Gladiolus

46. Thrips IPM Sanitation Remove weeds that act as a thrips refuge. Remove and destroy crop residues after harvest. Remove all soil debris from greenhouse. Screen windows, vents, and fans. Pasteurize soil to kill immature thrips.

47. Thrips Chemical Control Treat at 3-5 day intervals with very good coverage Rotate chemicals to prevent WesternFlowerThrips resistance Mesurol Spinosad (Conserve)* Avid Pedestal (IGR) Click here: thrips *Spinosad if used continuously will cause the insects to become resistant to its effects. Click here: http://www.growcom.com.au/VegIndustry/veg_info_download/Newsletters/WFT%20Newsletter%203%20Dec%2005%20final.pdf Click here: thrips *Spinosad if used continuously will cause the insects to become resistant to its effects. Click here: http://www.growcom.com.au/VegIndustry/veg_info_download/Newsletters/WFT%20Newsletter%203%20Dec%2005%20final.pdf

48. Order Diptera Flies, gnats, mosquitoes, midges Fungus gnats Shore flies, Scatella stagnalis. Only 1 pair of wings � second pair are modified into halteres Complete metamorphosis Adults have piercing-sucking or sponging mouthparts. Larvae have chewing mouthparts and feed on roots, stems, fruit. A pair of capitate bodies used as balancers during flight of insects of the order Diptera. They represent the rudimentary posterior wings of these insects pair of capitate bodies used as balancers during flight of insects of the order Diptera. They represent the rudimentary posterior wings of these insects A pair of capitate bodies used as balancers during flight of insects of the order Diptera. They represent the rudimentary posterior wings of these insects pair of capitate bodies used as balancers during flight of insects of the order Diptera. They represent the rudimentary posterior wings of these insects

49. Fungus Gnats Distinguished by the long, many-segmented antennae. Weak flier Feed on decaying organic matter in potting mix or decaying plants

50. Fungus Gnat Adult

51. Fungus Gnat Larvae

52. Fungus Gnat Damage Feed on soil fungi, algae, and decaying organic matter. May feed on root hairs or tunnel into roots when populations are high.Feed on soil fungi, algae, and decaying organic matter. May feed on root hairs or tunnel into roots when populations are high.

53. Fungus Gnat Monitoring Monitor with sticky traps placed horizontally at the crop canopy. Place potato wedges on growing medium surface to monitor larval populations. Leave in place for 3-4 days then look for larvae feeding on cut surface.

54. Shore Flies Nuisance insect. Short antenna Strong, fast flier 5 light spots on darker wings. Larvae have opaque bodies without distinct head capsules. Fungus gnats and shore flies occur nearly everywhere that greenhouse plants are grown. The adults of both groups are mostly nuisance pests, but can carry around one or more important species of plant disease-causing agents. The adults of each insect group are shown in Figure 1. Note that the fungus gnat has long antennae and legs, and the head is quite small in relation to the body. The shore fly adult resembles a small house fly (It is about the size of a fruit fly), the antennae are short, and the head is relatively large with red eyes. In addition, shore flies have small whitish spots on their wings. Fungus gnats and shore flies occur nearly everywhere that greenhouse plants are grown. The adults of both groups are mostly nuisance pests, but can carry around one or more important species of plant disease-causing agents. The adults of each insect group are shown in Figure 1. Note that the fungus gnat has long antennae and legs, and the head is quite small in relation to the body. The shore fly adult resembles a small house fly (It is about the size of a fruit fly), the antennae are short, and the head is relatively large with red eyes. In addition, shore flies have small whitish spots on their wings.

55. Fungus Gnat & Shore Fly Adults

56. Shore Fly Damage & Habitat Shore fly damage is fly speck. Habitats with a lot of algae will promote shore fly outbreaks. Look under benches and other water pooling places.

57. Fungus Gnat & Shore Fly IPM Eliminate breeding areas Drain wet areas. Dispose of infested growing media. Remove all plant debris. Avoid over watering plants. Avoid over fertilizing plant which will promote algae growth.

58. Fungus Gnat & Shore Fly Chemical Control Citation Orthene Dursban Adept Distance Sanmite Permethrin Nematodes for fungus gnat Gnatrol (B.T.I.) Adults are attracted to lights and are often first noticed at windows. Larvae or maggots, which feed in soil high in orangic matter, can injure the roots of bedding plants, African violets, carnations, cyclamens, geraniums, poinsettias and foliage plants. Plant symptoms may appear as sudden wilting, loss of vigor, poor growth, yellowing and foliage loss. Some are serious pests in mushroom houses. Fungus gnats inhabit fungi or dead plant materials and are harmless to humans and animals. Adults are attracted to lights and are often first noticed at windows. Larvae or maggots, which feed in soil high in orangic matter, can injure the roots of bedding plants, African violets, carnations, cyclamens, geraniums, poinsettias and foliage plants. Plant symptoms may appear as sudden wilting, loss of vigor, poor growth, yellowing and foliage loss. Some are serious pests in mushroom houses. Fungus gnats inhabit fungi or dead plant materials and are harmless to humans and animals.

59. Mites Spider mites Cyclamen mites Broad mites Not insects! 4 pair of legs not 3 No life stage has wings Damage is bronzing, webbing, & stipplingNot insects! 4 pair of legs not 3 No life stage has wings Damage is bronzing, webbing, & stippling

60. Spider Mite Life Cycle Eggs are laid in plant tissue and each female is capable of laying up to 120 eggs depending on the host plant. Larvae are small and white and only have 6 legs. They feed protected in flower buds. After they molt they become 8-legged nymphs that resemble the adults. Pupate in soil or leaf litter. Adults feed in protected plant parts.Eggs are laid in plant tissue and each female is capable of laying up to 120 eggs depending on the host plant. Larvae are small and white and only have 6 legs. They feed protected in flower buds. After they molt they become 8-legged nymphs that resemble the adults. Pupate in soil or leaf litter. Adults feed in protected plant parts.

61. Two-spotted Spider Mite Oval, yellow-green with two large, dark spots Webbing, bronzing, stippling Worse in hot, dry conditions Mites feed in protected plant parts-underside of leaves Adult twospotted spider mites are very small (ca. 1/60 inch in length), eight legged arthropods (nymphs have 6 legs) with a black spot on each side of their bodies. Color of the mites is variable ranging from white to light red. The eggs of the mites appear like small clear or pale marbles when viewed through a good hand lens. The twospotted spider mite is widely distributed and a common pest of orchards and nursery plants. When environmental conditions are hot and dry - such as during a drought, spider mites multiply rapidly and become a pest of fields crops such as corn, soybeans and cotton. Adult twospotted spider mites are very small (ca. 1/60 inch in length), eight legged arthropods (nymphs have 6 legs) with a black spot on each side of their bodies. Color of the mites is variable ranging from white to light red. The eggs of the mites appear like small clear or pale marbles when viewed through a good hand lens. The twospotted spider mite is widely distributed and a common pest of orchards and nursery plants. When environmental conditions are hot and dry - such as during a drought, spider mites multiply rapidly and become a pest of fields crops such as corn, soybeans and cotton.

62. Chemical Control of Spider Mite Mites are resistant to most insecticides therefor the following must be used. Hexygon Ovation Tetrasan Cinnamite Avid Talstar Sanmite Hexygon is a highly active mite ovicide and larvicide. Hexygon provides effective control of major tetranychid mite species with long lasting residual activity, yet is non-disruptive to beneficial mite and insect species. It is recommended for use as a foliar application in ornamental plants, non-bearing fruit and nut trees and vines growing in nurseries, and mature ornamental plantings. Hexygon is a highly active mite ovicide and larvicide. Hexygon provides effective control of major tetranychid mite species with long lasting residual activity, yet is non-disruptive to beneficial mite and insect species. It is recommended for use as a foliar application in ornamental plants, non-bearing fruit and nut trees and vines growing in nurseries, and mature ornamental plantings.

63. Cyclamen Mite Microscopic creatures. Hide inside buds & flowers. Inject a toxin while feeding. Low temps and high humidity favors outbreaks. Damage mimics physiological disorders.

64. Cyclamen Mite Chemical Control Can be controlled in water bath 110 OF for 15 minutes Avid Thiodan Miticides? Cyclamen mites were first reported as a pest in the United States in 1898. Adult mites are very small, less than 1/100 of an inch long, and cannot be seen without the aid of a microscope. They also tend to hide in dark, moist areas within tender buds or deep within the flower further hindering detection. Cyclamen mites are shiny and elliptical in shape with four pair of legs. Females are translucent yellow-to-orange whereas males are light brown with a claw on each back leg. Broad mites are slightly smaller than cyclamen mites and are colorless-to-pale brown with a white stripe down the center of their backs. One way to distinguish cyclamen mites from broad mites is by the egg stage. Cyclamen mite eggs tend to be laid in dark, moist areas. Eggs are smooth, elliptical and about 1/2 the size of the adult female. Broad mite eggs are elliptical but are covered by small whitish bumps that look like rows of diamonds. Broad mite eggs tend to be laid so they are more exposed on the underside of the leaf or stem surface than cyclamen mite eggs.Cyclamen mites were first reported as a pest in the United States in 1898. Adult mites are very small, less than 1/100 of an inch long, and cannot be seen without the aid of a microscope. They also tend to hide in dark, moist areas within tender buds or deep within the flower further hindering detection. Cyclamen mites are shiny and elliptical in shape with four pair of legs. Females are translucent yellow-to-orange whereas males are light brown with a claw on each back leg. Broad mites are slightly smaller than cyclamen mites and are colorless-to-pale brown with a white stripe down the center of their backs. One way to distinguish cyclamen mites from broad mites is by the egg stage. Cyclamen mite eggs tend to be laid in dark, moist areas. Eggs are smooth, elliptical and about 1/2 the size of the adult female. Broad mite eggs are elliptical but are covered by small whitish bumps that look like rows of diamonds. Broad mite eggs tend to be laid so they are more exposed on the underside of the leaf or stem surface than cyclamen mite eggs.

65. Broad Mite Broad mites inject a toxin from their saliva as they feed. Leaves become twisted, hardened and distorted with bronzed lower surfaces. Young terminal buds can be killed. Leaves frequently turn downward. Broad mites have a wide host range and can feed on African violets, ageratum, begonia, cyclamen, dahlia, gerbera, gloxinia, hibiscus, ivy, jasmine, impatiens, New Guinea impatiens, lantana, marigold, snapdragon, verbena, and zinnia. Broad mites can also infest vegetable bedding plants such as beans, peppers and tomatoes.Broad mites inject a toxin from their saliva as they feed. Leaves become twisted, hardened and distorted with bronzed lower surfaces. Young terminal buds can be killed. Leaves frequently turn downward. Broad mites have a wide host range and can feed on African violets, ageratum, begonia, cyclamen, dahlia, gerbera, gloxinia, hibiscus, ivy, jasmine, impatiens, New Guinea impatiens, lantana, marigold, snapdragon, verbena, and zinnia. Broad mites can also infest vegetable bedding plants such as beans, peppers and tomatoes.

66. Chemical Control of Broad Mites Broad mites damage flowers and foliage of begonia and cyclamen and others, and bronze the lower leaf surfaces. Their toxic saliva causes twisted, hardened and distorted growth in the terminal of the plant. Damage looks like that of an herbicide. 60 families of plants may be attacked Use Avid, Thiodan, or Sulfur- but not pyrethroids Miticides? Some are effective, others not. Eliminate weed sources, practice clean cultivation Avid is expensive, but one of the Best Miticides available.Avid is somewhat systemic in that it penetrates intotreated foliar plant cells where it remains activewhile the material that remains on the leaf surface rapidly breaks down. (source: Texas A & M University, Agricultural Extension Service) Usage is 1/4 teaspoon per gallon of water,so the 8oz bottle will go a long wayIt's VERY IMPORTANT to use Chemical gloves when working with AvidAlso wear long sleeves, pants, eye protection and a maskAfter treatment is done, remove clothes for washing and take a showerEven though spraying works very well, some people want to hand dip each plant insteadThe advantage of this, is that you cover 100% of the plant with AvidPlus you won't have to worry as much with breathing in the Avid from the spray mistBut still wear long sleeves, gloves and eye protection because you will still splash Avid Avid is expensive, but one of the Best Miticides available.Avid is somewhat systemic in that it penetrates intotreated foliar plant cells where it remains activewhile the material that remains on the leaf surface rapidly breaks down. (source: Texas A & M University, Agricultural Extension Service) Usage is 1/4 teaspoon per gallon of water,so the 8oz bottle will go a long wayIt's VERY IMPORTANT to use Chemical gloves when working with AvidAlso wear long sleeves, pants, eye protection and a maskAfter treatment is done, remove clothes for washing and take a showerEven though spraying works very well, some people want to hand dip each plant insteadThe advantage of this, is that you cover 100% of the plant with AvidPlus you won't have to worry as much with breathing in the Avid from the spray mistBut still wear long sleeves, gloves and eye protection because you will still splash Avid

67. Decision Making What is the �best� action to take based on the information collected? Consider: Cost of intervention ($$) Value of crop Potential for Damage Impact of Damage Effectiveness of intervention

68. Follow-up! Evaluate the effectiveness of the intervention implemented! Did it work? Why not? What is your next step? Maintain records of problems and solutions Such information is invaluable for future situations

69. Sources for Supplies Greenhouse, Greenhouses, Greenhouse Supplies and Greenhouse Information. E.C. Geiger 800-443-4437 http://www.hortnet.com/ecgeiger/ Hydro-Gardens Inc. 800-634-6362 Hydroponic Supplies, Greenhouses, Greenhouse Supplies, Commercial Greenhouses, Hobby Greenhouse, Greenhouse Kit, H Gemplers 800-382-8473 GEMPLER'S - About Us

70. ALWAYS Read and Follow Label Directions! Pesticide Labels Change Frequently!

71. Educate yourself Attend workshops, field days, short-courses, seminars, etc. that are vital to learn about the current pest management strategies and approaches and keep yourself informed on developing pest problems through your Extension Service and the Internet. . Dr. R.Chris Williamson Department of Entomology