1. Pest Management Tactics & Strategies Covers chapters 8 – 17 in text Includes all major tactics categories: –Biological control –Cultural control –Pesticides –Mechanical/Physical controls –Behavioral-based control methods –Regulatory-based concepts Also includes all factors necessary for choosing/deciding among controls –Monitoring methods –Decision tools

2. Pest Management Decision Categories Tactical vs Strategic Preventative vs. Curative In-Season vs. Intra-Season Control vs. Non-control (i.e. monitoring) Single Dimension vs. multidimensional –Temporal: Single Period vs. Multiperiod –Biological: Single spp. (pest) vs. Multiple spp. (pests, beneficials, other non-targets) –Economic: Immediate payback vs. multiple economic considerations.

3. Who makes IPM Decisions? Growers who manage the pests? Consultants who make recommendations to growers? Extension specialists who develop educational/training materials? Researchers who decide which topics to research? Administrators who decide which things to fund? Others?

4. Pest Management Strategic Plans Driven by national programs Closely associated with Crop Profiles and Crop TimelinesCrop Profiles Crop Timelines Provide a framework for IPM decisions No specific format, but most include: –Pest profiles for each important pest –Management tactics currently used –Additional needs in research, extension, training Decisions about how IPM needs to advance in a particular cropping system. A planning tool.

5. Assignment Split into groups of 3 Each group finds a Pest Management Strategic Plan Distribute the web site for the plan over IPM-L by Thursday, Feb. 19. Each group discusses their plan in class on Wed., Feb. 25 Suggestion: One person discusses the pests, one discusses the tactics, one discusses the needs.

6. Most Decisions are Tactical & Follow a Procedure 1.Identify pest 2.Determine pest population density 3.Evaluate potential damage 4.Review available control tactics 5.Consider possible interactions with other pests 6.Evaluate legal/environmental issues 7.Make a decision

7. The Decision Itself Must rely on a priori objective criteria. Often an economic framework. Four possibilities A.No action B.Reduce Pest Population C.Reduce Crop Sensitivity to Damage D.B & C above 8.Follow-up to confirm expected outcome

8. An Alternative View to Fig. 8-1

9. Identification: Focuses on early seasonality factors Pathogens – Identification of conditions leading to disease often more important than identifying the pathogen itself. Weeds – Seedling identification is the main issue Arthropods – Knowing when immatures will be present often a key to identification of pest problems.

10. Monitoring Synonymous with “Scouting”, “Sampling”, “Pest Surveillance” Normally conducted to gather information needed by a decision tool Types of decision tools that using monitoring info include tools that: –Time preventative treatments –Determine whether curative controls are needed –Determine whether either of the above were effective –Select specific measures from several choices

11. Monitoring Determines: Crop Status (development stage, stand density, standing crop, etc.). Identity of pests Phenology Age distribution Number or size of population –Absolute (#/unit habitat or area) –Relative (#/unit effort) –Qualitative (Scaled from “low” to “high”)

12. Requirements of Monitoring Methods Simple to use Fast Inexpensive Applicable to a broad range of pests Reliable for decision making purposes

13. Decision-making reliability is crucial Credibility of IPM depends on decisions being correct Decisions have to be made with imperfect information & much of the imperfection is in monitoring data Every decision has a risk of being wrong Lesson: We must understand how frequently our decisions are incorrect and if there is a bias for overcontrol or undercontrol in our mistakes.

14. Reliability for Decision Tools I II III IV Pest Population on One Sample Date Pest Population on Next Sample Date Max Tolerable Pest Pop.

15. Consider this situation Maximum Tolerable Level Time (Weeks) Pest Population Density

16. Say we sample at weekly intervals Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678

17. You have to make decisions at each sampling date Maximum Tolerable Level I Correct decision to control II Incorrect decision to do nothing III Correct decision to do nothing IV Incorrect decision to control Time (Weeks) Pest Population Density 12345678 III II III I IV III

18. Construction of the decision diagram from sampling data I II III IV Pest Population on One Sample Date Pest Population on Next Sample Date Max Tolerable Pest Pop. Time (Weeks) Pest Population Density 12345678 III II III I IV III X Y

19. Example: Find 15 pest individuals at first sample, 20 on the second sample I II III IV Pest Population on One Sample Date Pest Population on Next Sample Date Max Tolerable Pest Pop. Time (Weeks) Pest Population Density 12345678 III II III I IV III 15 20 15 20

20. Example: Then, on the third week, we find 40 pest individuals I II III IV Pest Population on One Sample Date Pest Population on Next Sample Date Max Tolerable Pest Pop. Time (Weeks) Pest Population Density 12345678 III II III I IV III 20 40

21. Not all decision points are equally susceptible to error Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678 III II III I IV III

22. Reliability for Decision Tools I II III IV Pest Population on One Sample Date Pest Population on Next Sample Date Max Tolerable Pest Pop.

23. Reliability Depends on Several Factors Specific species being monitored Sites (site selection is important) Specific technique being used Number of samples taken –Number at each site & number of sites Weather Observer (Scout) – Scout training is emphasized Other minor effects: –Field size, location, & aspect –Time of day (pests with diurnal activity) –Field history

24. Some of These are Linked Specific species being monitored Sites (site selection is important) Specific technique being used Number of samples taken –Number at each site & number of sites Weather Observer (Scout) – Scout training is emphasized Other minor effects: –Field size, location, & aspect –Time of day (pests with diurnal activity) –Field history

25. Reading for Friday Bring your blue books with you to class Before class, look through them & be able to locate the insect, weed, and pathogen monitoring sections of each book. Over the next few weeks (i.e. by the next exam), be able to (1) describe at least one monitoring method for each pest group in each cropping system, (2) compare two sampling methods from different crops, for the same pest group (e.g. insects) and in the same generic category (absolute, relative, qualitative).

26. Conclude Pest Monitoring Closely read the material on “Techniques for assessing pest populations”, pp. 183 – 197. –There will be an exam question here. –We won’t discuss it in lecture but may refer to the material as if you are very familiar with it. –Be sure & apply this section to your analysis in your term paper.

27. Decision Making Have discussed the “Maximum Tolerable Level” but have not defined it. Several Points to Make: –More than 1 “Level” is usually needed. –There are many kinds of such levels (cf. p. 200 – 201 in text for one list). –“Action Levels” or “Thresholds” are one general method of decision making. We will discuss the other one (Optimization) later. The leader in this field has been L. Pedigo. Be sure & read his article in the “Reading Assignments”

28. The General Problem Maximum Tolerable Level Time (Weeks) Pest Population Density

29. We actually see this: Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678

30. One problem is that we need to allow for management response time – The time between when a control decision is made and when it takes effect Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678 Assume it takes 1 week to decide a control is needed, apply it, and for it to work Decision must be made here

31. The other problem is uncertainty Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678

32. Solution to both problems (mgmt response time & uncertainty) is to create two levels Maximum Tolerable Level Time (Weeks) Pest Population Density 12345678 Economic Threshold Economic Injury Level The maximum pest level that one is willing to tolerate. The pest level at which action must be taken in order to avoid exceeding the EIL.

33. Quick Notes on EILs & ETs ET is always < EIL Units of ET & EIL are the same –Often pest density (absolute or relative) –Can also be injury (e.g. % defoliation) –Can also be implicit factors (e.g. leaf wetness) EIL & ET are hard numbers calculated from equations developed through field research.

34. The Basic EIL Model The basic concept is that the EIL is the point at which the cost of a control = the value of damage that will be avoided by the control. Value of damage avoided is a product of: Crop market value (V) Pest population density (P) Injury caused by each pest individual (I) Damage resulting from that injury (D) Proportion of total damage that cannot be avoided by the control (K)

35. The Basic EIL Model

36. Example Assume: –It costs $50/A to apply a given control (C) –A crop is worth $40/bushel (V) –Leaf area equal to two leaves/row foot are eaten by each pest individual/plant (I) –The loss of two leaves/row foot results in the loss of one bushel/A (D) –Even if you apply the control, you will still lose 10 % of the crop (K = 0.1, no units)

37. Example, Continued

38. Understanding the Units is Key

39. Here’s how the units balance Result: EIL = 6.25 pests/plant

40. One of the principal advantages of EILs is their objectivity and scientific basis I, D, and K are determined empirically through field & laboratory experimentation. C is, for the most part, easily determined. For most agricultural crops, V is commonly available.

41. The principal source of subjectivity is in “Value”: Ex: Tree Crops & Gypsy Moth Time (Weeks) Pest Population Density Resort Owner Lumber Company Municipality Forest Ranger Note that in all of these cases: C, I, D, & K are all the same. Only V changes.

42. Some examples of EILs & their derivation. EIL for Mexican Bean Beetle in Soybean – Details the development of an EIL.EIL for Mexican Bean Beetle in Soybean EILs for sorghum midge on sorghum – See Table 1 in the middle of the article.EILs for sorghum midge on sorghum Common stalk borer in Nebraska corn Sweet potato whitefly on cantaloupe

43. How are ETs calculated? Most common method is heuristic. Most common rule of thumb is 1/3 EIL. Two examples of more formal methods are: (1)ET = EIL/r (2) ET = EIL/(expected rate of change in pest population)

44. General notes on ETs ETs are the predictive part of an EIL/ET pair – one acts on an ET in order to prevent the EIL from being exceeded. ETs are one type of “Action Threshold”. Other types were in Pedigo & your text (pp. 201 – 202). Note your text’s discussion of limitations of thresholds.

45. Advantages of Thresholds Conceptually easy to understand makes them easy to implement/adopt. Can also be represented in many formats: single numbers, tables, charts. Scientific basis to threshold criteria Flexibility gives broad applicability –Can be applied to a variety of pests in many situations –Can utilize many variables as the action variable. Climatic variables often used for pathogens. –Have been extended to take into account many other issues. Examples include Age distribution Multiple controls (e.g. biocontrol) Environmental Impacts (i.e. macroeconomic “C” values) Risk

46. Closely read the remainder of this chapter This is the only place where the following topics are discussed: –Use of field history –Field location & size –Monitoring climate –Use of computer/mathematical models –Aesthetic effects –Risk Assessment –Economics

47. Tactics Cultural Tactics (Chapter 16) Biological Control (Chapter 13) Pesticides (Chapter 11) Resistance, Resurgence (Chapter 12) Host Plant Resistance (Chapter 17) Behavioral Control (Chapter 14) Physical & Mechanical Tactics (Chapter 15) Legislative Prevention (Chapter 10)

48. Cultural Management of Pests Change the way the crop is grown so as to –Make crop less suitable to pests –Make crop more suitable to biocontrols –Make crop better withstand pest attack All are preventative tactics, most target pest complexes. Many individual types of tactics, each of which has a narrow application range. Read Introduction on p 413 - 414

49. Basic Categories/Examples of Cultural Techniques Prevention/Preplant –Ex: use weed-free seed Field Preparation & Planting –Ex: increase plant spacing to reduce disease Cropping Tactics –Ex: use barrier crops to help exclude insects Harvest Tactics –Ex: harvest early to reduce yield loss Sanitation –Ex: pick up prunings to reduce pathogen inoculum

50. Good situations for cultural controls – Any of these will lead to the use of cultural controls Multiple simultaneous pests susceptible to 1 control method Crop has broad flexibility with respect to specific tactic but pest(s) does not Pest complex: –Has one or more key pests vulnerable to environmental manipulation –Lacks pests capable of causing severe damage at low density –Contains one or more pests that lack better control alternatives

51. Benefits of cultural controls Often easily incorporated into the production system Predictable level of control, even if partial Fast acting As a group, relatively sustainable

52. Disadvantages of Cultural Controls Some are not environmentally benign (e.g. conventional tillage, residue burning) May alter crop value or gross income (planting date, harvesting, spacing) Some are labor/energy intensive (pruning, tillage) Widespread adoption may be low Many conflicts

53. Conflict Illustration Time Pest Density Crop’s Maximum Susceptibility Period Normal Planting Date Late Planting Date

54. Conflict Illustration Time Pest Density Crop’s Maximum Susceptibility Period Normal Planting Date Late Planting Date Pest A Pest B Often better to think of cultural control tactics as altering the pest complex rather than controlling it.

55. Conflicts Occur with: Agronomic Traits Other Pests Markets Other Cropping Practices Begin Discussion of Cultural Control Categories

56. Basic Categories/Examples of Cultural Techniques Prevention/Preplant –Ex: use weed-free seed Field Preparation & Planting –Ex: increase plant spacing to reduce disease Cropping Tactics –Ex: use barrier crops to help exclude insects Harvest Tactics –Ex: harvest early to reduce yield loss Sanitation –Ex: pick up prunings to reduce pathogen inoculum

57. Prevention/Preplanting Tactics Site selection Preventing pest transport (equipment, soil) Use pest-free seed/transplants/rootstock

58. Field Preparation & Planting Cultivation & fertility Plant & row spacing Planting date (early vs late) Planting method (depth, insertion method) Mulches – organic & synthetic

59. Cropping Tactics Trap/Barrier Crops –Trap crops are destroyed with the pest –Barrier crops are on field perimeter Intercropping – Two or more useful crops Cultivar mixtures – Different cultivars may have to be planted in different fields to create a “cultivar patchwork”. Multilines will be discussed in HPR. Water Management

60. Cropping Tactics – Crop Rotation Intercropping in time Especially effective against soil-based pests: Weeds, soil-borne pathogens, root- feeding insects For weeds: –Changes weed complex –Not stand alone weed mgmt, instead used to facilitate weed mgmt

61. Harvest Tactics Harvest timing (early vs late) -- may use early/late varieties, dessicants, defoliants, or other growth regulators. –Crop matures before pests build up –Harvesting operation itself causes extensive mortality. Harvest method Partial Harvesting -- Prevents movement to high value crops –Maintains young age structure –Concentrates natural enemies (usually more mobile)

62. Sanitation Residue Removal Burning/Flaming Pruning (Removing Part of a Plant) –Infected/Infested host tissue –Foliage that provides pest access –Alters canopy microclimate Roguing (Removing an Entire Plant) –Crop hosts –Alternate hosts Removing Other Resources (Often in Structures) –Harborage sites –Food/water sources

63. Biological Control One of the oldest pest management tools One of the most complex Excludes some biologically-based tools –Use of pests own behavior, biology, ecology –Use of crop resistance As a result, many definitions

64. Biological Control Defined “The use of parasitoid, predator, pathogen, antagonist, or competitor population to suppress a pest population making it less abundant than it would be in the absence of the biocontrol agent Emphasis on “population” helps exclude microbial pesticides

65. Biological Control Natural Control vs Biological Control –Natural Control is unmanaged, Biological Control is managed. Definition of “managed” can be pretty loose. Natural Enemy = NE = “Biological Control Agent” & “Biocontrol Agent” –Any non-crop species that is antagonistic to the pest. Includes predators, parasites, parasitoids, pathogens, competitors. –May be managed or unmanaged.

66. Biocontrol Ideal Time EIL Population Density Biocontrol agent introduced Pest Biocontrol Agent

67. Three components interact to produce different biocontrol approaches Cropping System Pest Complex Natural Enemy Ideal Emphasize the NE-Pest Interaction NE lacks persistence, emphasize introduction Emphasize effect of cropping system on NE

68. Cropping System Characteristics Conducive to Biocontrol Stability Abiotic environment supports NE’s –Temperature, moisture & shelter are all available as needed by NE –Soils support soil-based NE’s Biotic environment supports NE’s –Alternative food sources available –Food for all life stages available Management practices compatible Crop should have some damage tolerance

69. Biocontrol usually allows some injury and/or damage EIL Population Density Time } Biocontrol agent population always lags behind the pest population. This allows the pest population to build up to some extent. ET = EIL/3 ET > EIL/3

70. Pest complex characteristics conducive to biocontrol Few species in the target niche Stable species composition Few key pests, few direct pests Ideally, minor pest species can act as alternate hosts/prey Note the benefits of biocontrol, pp 338 - 339

71. Costs/Disadvantages of Biocontrol Usually requires change in management practice Increases scouting effort Intrinsic time delay Increased risk –New NE’s may cause harm –Uncertainty about NE requirements/reliability –Always a potential for pest to escape control Fundamentally incompatible with other control tactics

72. Characteristics of Effective NE’s Can detect pest populations at low densities Rapid population growth relative to pest population High pest destruction rate per capita Synchronized phenology Persistence at low host density Persistence over cropping seasons/rotations Tolerant of management actions Willingly adopted by pest managers & growers

73. Common Trade-off Quesitons Generalists vs. specialists. Multiple vs. single biocontrol species

74. Generalists vs. Specialist NE’s Disadvantages of generalists: –Usually have lower numeric response –Kill fewer pests/unit time/NE –May be attracted to other species Advantages of generalists: –Better survival when pest population is low –More likely present at pest establishment –Multiple generalist species can co-exist as a community (greater stability & reliability)

75. Phase Plane – Specialist NE Population Density Time Pest Population Natural Enemy Population A specific phase plane’s characteristics are determined by (1) the biological parameters of the NE and Pest and (2) how closely the NE and Pest population dynamics are coupled. Specialists tend to be highly coupled.

76. Pest Max Elementary Implications of the phase plane Natural Enemy Population Pest Population Must be < EIL Stable -- Good Too Many Pests, Two Few NE’s – Pests Have Escaped Control Too Few Natural Enemies -- Pest Resurgence Danger NE Max NE Min Pest Min Too Many NE’s for Pest Pop. – NE Crash Imminent Outcome Uncertain – Probably Bad

77. The “good” area often identified in decision guides as NE/pest ratios Spider Mite Examples Predator mite/pest mite (spider mite) on apples must be at least 1:10 in Washington raspberries.1:10 In N. Carolina apples:In N. Carolina apples –1 Predator mite/18 pest mites –25 Coccinellid predators/5 trees European red mite in W. Virginia orchardsW. Virginia orchards –If mites > ET, no spray if predator/mite > 2.5

78. Multiple vs. Single NE Introductions Denoth et al. 2002 analyzed 167 biocontrol introduction projects –Multiple introductions increased success for weed control, decreased success for insects –In > half, a single NE species was ultimately responsible for almost all realized biocontrol. –Recommend that multiple introductions should be used with restraint when attacking insect pests