Pest Management ConceptsFor Turf

David J. Shetlar, Ph.D.The BugDoc

Landscape EntomologistThe Ohio State University

Traditional Definition(based on field crops)

IPM is a decision making process which selects, integrates, and implements pest control tactics (biological, chemical or cultural) based on predicted economic, ecological, and sociological consequences.

Integrated Pest ManagementIPM

Integrated Pest Management(IPM)

ChemicalChemical

BiologicalBiological CulturalCultural

Theoretically, chemical, biological and cultural control tactics are “equal” in importance!

Current ideology is that biological and cultural tactics are preferred!

Traditional Approaches(based on crops)

• sample pest populations on a regular basis.

• develop pest economic injury levels.

• determine economic threshold levels (action thresholds) for each crop and pest.

IPM Principles and Concepts

Problems Applying Field Crop Concepts to Turfgrass Areas

• turfgrass is an aesthetic “crop.”

• turfgrass is a perennial, not easily replaced if damaged.

• turfgrass is often maintained on the edge of stress or under high stress!

• it’s easier to spray than monitor!

IPM Principles and Concepts

Urban Approaches(for landscapes, Raupp et al.)

• Key Plants - plants prone to damaging pest problems. (Turf? – are all turf species equally susceptible to pests?)

• Key Pests - pests that can cause serious damage or plant loss. (Turf? – area all turf pests equal in their potential to damage turf?)

Applying Urban Landscape IPM Principles and Concepts to

Turfgrass

Current Approach to Ornamental Plant Maintenance

• MAP landscape, identifying key plants and key pests.

• Evaluate individual plants and consult with owner about desires for plants – maintenance, push growth, etc.

• Use targeted pesticide applications.

• Recommend “crop” rotation!?

Using Ornamental Plant Maintenance Approach with Turf

• MAP turfgrass (individual lawns, neighborhoods, golf course, sport fields) noting susceptible turf and pest type and locations.

• What is desired for each turf area? (front year vs back yard; greens vs fairways; practice fields versus varsity field).

• Use targeted (area) pesticide applications.

• Recommend “crop” rotation!? (turf renovations?)

Grub Sampling on Golf Fairway

Grid Pattern

Zig-zag Pattern

Notes: A golf course can be mapped for grub populations with a crew of four people (using the grid pattern) or even just one person (using the zig-zag pattern). Each sampler uses a golf course cup changer to pull turf cores which are inspected for the number of grubs present. In the grid pattern, three samplers pull plugs and yell out the results to the recorder. An 18-hole course can be sampled in one to two days. Where core samples average one grub per core (each sample is 1/10th square foot), grub damage or animal digging will result and controls are needed.

The problem with this method is that white grubs are most easily sampled for when they are in the second instar stage. By this time, you will have to select an insecticide that has good curative action. Many of the newer grub insecticides work best when used as a preventive. In this case, a better strategy would be to use historic records. If an area has experienced grub damage in the past, it is likely at risk in the future, as long as thatch and organic matter levels remain high.

Grub Sampling on Home Lawn

Notes: Grub sampling in lawns and sport fields is rarely done, but is just easy to perform as on golf course fairways. Just use a golf course cup changer and sample on a grid that is 15 to 20 ft centers. In home lawns, shady and thin turf rarely has grubs, so these areas don’t have to be sampled.

In most cases, using historic records is a good predictor of grub damage potential. Research has shown that lawns, grounds or sport fields damaged by white grubs in one season are likely at 80% or higher risk of repeating the damage the next season!

Sampling Turfgrass Insects

• Hands-and-Knees! (billbugs, chinch bugs, sod webworms, etc.)

• Tug Test – billbugs

• Soap Flush – caterpillars & mole crickets

• Soil Samples (cup changer, shovel, knife, etc.) – white grubs, billbug larvae, ground pearls, etc.

Plant Health CareCurrent Thinking

In Plant Health Care (PHC), the concept of

Integrated Pest Management (IPM) is only

ONE component of the system - the one

dealing with "intervention" after a plant

(turf) stress has been identified as being

caused by a pest.

Plant Health Care

Stress (or Pest)Management

Plant Evaluation

PlantPlant ClientClient

Intervention?

Integrated Pest Management

MONITORMONITORPESTSPESTS

InsectsInsectsDiseasesDiseases

WeedsWeeds

Chemical Controls

Cultural ControlsBiological Controls

Plant Client

Stress (or Pest)Management

Plant Evaluation

Intervention?

In Plant Health Care,

the PLANT and its OWNER

(client, manager, etc.) are

the central focus of the

system

MONITORPESTS

InsectsDiseases

Weeds

Chemical Controls

Cultural ControlsBiological Controls

In Integrated Pest Management,

the PESTS are the central

focus of the system

Turf Health Care PyramidLawns

Soil, Precipitation, Temperatures, SunSoil, Precipitation, Temperatures, Sun

Species, Fertility, Mowing, Species, Fertility, Mowing, Irrigation, ThatchIrrigation, Thatch

WeedsWeeds

InsectsInsects

DiseaseDisease

Notes: The base foundation for the turf in lawns is the environment in which it will be grown (soil conditions, annual rainfall, annual temperature ranges, and amount of available sun). This environment dictates the grass species and cultivars that should be considered and selected. General maintenance then has a major impact on the turf “health” – fertilization levels and types, mowing height and frequency, irrigation availability and frequency, core aerification and thatch management, etc.

Finally, the pest complexes (weeds, insects and diseases) have to be considered for each type of turf. For most lawns, weeds are the most common pests dealt with, followed by insects. Diseases are rarely controlled with fungicides in turf because of their cost.

Turf Health Care PyramidGolf Courses

Soil, Precipitation, Temperatures, SunSoil, Precipitation, Temperatures, Sun

Species, Fertility, Mowing, Species, Fertility, Mowing, Irrigation, ThatchIrrigation, Thatch

InsectsInsects

DiseaseDisease

WeedsWeeds

Notes: Notice that in golf course turf, the base foundations of the environment and maintenance remain the most important components for turf health, but the pests and importance of those pests (calculated by cost of management and risk of losing turf) has changed. Disease management ends up costing more and the risk of turf loss is high. While weed control may be less on some courses, I’ve factored in the costs of plant growth regulators and management of annual bluegrass. Of course, if you were in Florida, the cost of mole cricket control plus the other insects may push that section of the pyramid to be larger.

Pest Management Approaches

• Tolerance (do nothing)

• Mask Damage (fertilize, water, etc.)

• Preventive (eliminate populations early, often the adults or immatures before any possibility of damage occurs.

• Curative (eliminate populations that are sampled and found will likely cause damage.

• Rescue (damage has occurred)

The Target PrincipleHow Does The Pest Come Into Contact

With The Control?

• Location of Pest (Can you get the control to the target?)

• Stage of Pest (Is it susceptible? Is it feeding?)

Notes: When trying to control pests, whether with chemical or biological controls, one must keep in their mind exactly where the pest is located and is the pest going to come into contact with or ingest the control material?

An insecticide applied for white grub control, mixed with a foliar protectant fungicide, may be left to dry on turf foliage. Since the white grubs are in the soil-thatch interface, they will never come into contact, nor ingest this application!

On the other hand, intensive irrigation after applying an insecticide targeted for black cutworms may miss the target since the cutworms usually ingest insecticides while they eat turfgrass leaf blades at night.

Target Zones

Leaves & Stems – cater-pillars, mites, greenbugs, etc.

Stems & Thatch – chinch bugs, sod webworms, billbug adults, etc.

Soil-Thatch Interface – white grubs, mole crickets, etc.

Where do insecticides applied as sprays end up in this profile? Where do granular formulations go?

Where do grubs feed?

Ans:

Soil-thatch interface!

What do grubs eat?

Ans:

Organic matter, thatch and soil (oh yes, and roots)!

Japanese Beetle Life Stages

egg larva pupa adult

1st 2nd 3rd

instars

A study in California to determine the relative susceptibility of masked chafer first, second and third instar grubs to and insecticide, diazinon, found the following relative susceptibilities (using the amount of diazinon needed to kill the first instar as a unit of 1):

• First Instar – 1 unit

• Second Instar – 26 units

• Third Instar – 120 units!

Therefore, grub instar susceptibility is not a straight-line effect purely related to body weight!

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Japanese Beetle Annual Cycle

Preventive-Early Curative TimingTraditional Curative Timing

The Multiple Target Principle

Pests of turfgrass rarely occur one-at-a-time at any one time!

Therefore:

What would be all the potential targets influenced by a pesticide application?

Using the Multiple Target Principle

• What is the pest make up (TARGETS) over a season?

• When are the pests SUSCEPTIBLE to control?

• What is the SPECTRUM of activity of the pesticide being considered?

• What is the ACTIVITY PERIOD of the pesticide being considered?

Occurrence of Target Lawn Insect Pests

April May June July August Sept

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB-prv

• BB/l

• CB/n

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/l

• CB/n&a

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• CB/n&a

• SWW

• APH - prv

• GRB

• BB/a

• CB/a

• SWW

• APH - prv

Occurrence of Target Lawn Insect Pests

April May June July August Sept

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB-prv

• BB/l

• CB/n

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/l

• CB/n&a

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• CB/n&a

• SWW

• APH - prv

• GRB

• BB/a

• CB/a

• SWW

• APH - prv

Controlled with Conserve®

Occurrence of Target Lawn Insect Pests

April May June July August Sept

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB-prv

• BB/l

• CB/n

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/l

• CB/n&a

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• CB/n&a

• SWW

• APH - prv

• GRB

• BB/a

• CB/a

• SWW

• APH - prv

Controlled with MACH2®

Occurrence of Target Lawn Insect Pests

April May June July August Sept

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH - prv

• GRB

• GRB-prv

• BB/a

• BB/l-prv

• CB/a

• CB/n-prv

• SWW

• APH

• GRB-prv

• BB/l

• CB/n

• SWW

• APH

• GRB

• GRB-prv

• BB/l

• CB/n&a

• SWW

• APH

• GRB

• GRB-prv

• BB/a

• CB/n&a

• SWW

• APH

• GRB

• BB/a

• CB/a

• SWW

• APH

Controlled with Merit®

When Insecticides Don’t Work!

Applicators Usually State:

• Pest resistance

• Weak pesticide

Known Reasons for Failure:

• Incorrect rate

• Poor distribution

• Binding (adsorption)

• Hydrolysis (pH)

• Photodegradation

• Accelerated degradation

• Pest not in susceptible stage

• Pest resistance

Notes: Turf managers rarely want to admit that they were the reason that an insecticide didn’t work! They would prefer to think that the insects have developed some kind of resistance or something was wrong with the product. While many insecticides have a shelf life, most formulations will retain the required activity for several seasons (if stored properly). In order to be economically competitive, many companies recommend applications at near their margins of control. If application equipment is poorly calibrated (often not calibrated at all!), a product can be applied as much as 30% too high or too low! Some chemical compounds are susceptible to extremes of mix pH (acid or alkaline) so pay attention to any labels that recommend adjustment of mix pH. Other pesticides are susceptible to breakdown in ultraviolet light (direct sunlight). Immediate irrigation after an application can avoid this problem. Other pesticides are easily broken apart by soil-dwelling microbes (bacteria and fungi), and when “fed” a pesticide, these microbes can “learn” to “eat” the molecule, thereby cause almost immediate loss of efficacy. This will look like resistance, but the pest is still susceptible! Insect pupae don’t feed and thus, don’t ingest a pesticide, and finally, pest resistance DOES occur, but rarely!