Colorado Pesticide Exam Turf: IPM & Pesticide Application

What does the turfgrass industry in Colorado include?

home lawns, institutional grounds, industrial grounds, golf courses, athletic fields, and other recreational turf, parks, roadsides, airports, and cemeteries

The greatest segment of the industry

home lawns

Turfgrass is maintained for:

beautification, recreation, erosion control, and general utility purposes

Most important factors in maintaining good turf and preventing problems

selecting the right grass, mowing, watering, fertilizing, and thatch control

Pesticides should be used as an...

aid in turf management but not as a substitute for good cultural practices

Cool season grasses

bluegrass, tall fescue, and ryegrass

Warm season grasses

Bermudagrass, zoysia, and buffalograss

Process of diagnosing turfgrass problems

- determine kind of grasses involved

- find out why the problem occurred

- determine if the problem is best corrected by management practices, soil modification, or pesticides

- check to see if a chemical is labeled both for the turfgrass species and the problem

- recommend good cultural practices that will assist in turfgrass recovery

IPM

(Integrated Pest Management) an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices

uses current, comprehensive information on the life cycle of pests and their interaction with the environment

Four-tiered approach to IPM

1) set "economic" or "action thresholds"

2) monitor and identify pests

3) prevention

4) control

"Economic" or "Action thresholds"

a point at which pest populations or environmental conditions indicate that pest control action must be taken to prevent economic loss

Favorable pH of soils

between 6 and 7 (neutral)

Turfgrasses are selected based on:

- use

- growth environment (soil type, light, moisture)

- the desired appearance

- management level it will receive

- pest resistance

Turfgrass cultivars (varieties)

species selected for specific characteristics such as disease resistance, tolerance of unusual environments, and appearance

Biological control

use of bacteria, fungi, nematodes and parasitic or predaceous insects to control pest organisms

Genetic control

disease resistant cultivars

Prevention during planting

use seed or sod and plugs that are as pest free as possible

Pesticides are selected based on:

- application method and timing

- toxicity

- effectiveness

- host specificity

- cost

- persistence in the environment

Dry Flowables (DF)/Water dispersible granules (WDG)

form a suspension when mixed with water and require less agitation than wettable powders

Dusts (D)

formulations of pesticides on a dry particle that are designed to be applied dry

Emulsifiable concentrates (EC or E)

common liquid formulations of pesticides which have active ingredients that are insoluble in water

these formulations include the addition of an "emulsifier" which allows the pesticide to mix with water forming a "milky" suspension

Flowables (F)

formulations which can only be produced in solid or semisolid form, often ground into a fine powder and suspended into a liquid

Granulars (G)

dry formulations mixed onto fairly large particles of clay, ground corn cob or walnut hulls, or manufactured granules and applied as formulated without mixing

Microencapsulated pesticides

impregnated into tiny, slow release plastic beads and mixed into a liquid

Soluble powders (SP or S)

dry formulations that will go into true solution when mixed with water, may also be formulated as liquids

Wettable powders (WP or W)

formulated on a dry particle and contain ingredients that allow the particles to mix with water, resulting mixture is a suspension

Adjuvants

- reduce number of fine droplets

- decrease drift

- increase effectiveness of a.i.

- make application easier

Surfactants

used to improve spread of spray mixture on foliage, most commonly used to apply on plants with waxy or hairy leaves

Stickers

improve weatherability of spray deposit (washing by rainfall or irrigation)

Synergists

greatly increase the activity of insecticides by blocking the ability of the insect from breaking down the insecticide

Penetrants

increase the uptake of herbicides into a plant

Buffers

used in spray tanks to decrease breakdown of pesticides that occurs from exposure to alkaline (high pH) water conditions

Equipment choice is influenced by:

pesticide formulation, type and location of area (groundwater concerns), and frequency of applications

Tanks must be made of:

material that resists corrosion from various chemicals like polyethylene, fiberglass, and stainless steel

Pumps (and types)

move the pesticide from tank to nozzle, common types include roller, centrifugal, piston, and diaphragm

must be large enough to supply the volume needed for nozzles and to maintain the desired pressure

Pump requirements with abrasive materials (such as WP)

select gaskets, plunger caps, and impellers that are resistant to swelling and chemical breakdown

Agitators

mix the components of the spray mixture uniformly and for some formulations, keep the material in suspension

Two common types of agitators

hydraulic and mechanical

Hydraulic agitators

recirculates spray mix through nozzle jets located in the spray tank

Mechanical agitators

large revolving paddles inside the spray tank

Strainers

filter the spray mixture, protecting the working parts of the spray system and preventing clogged nozzle tips

Hoses

connect the tank and pump to the nozzles, should be made of synthetic rubber or plastic to resist solvents and oil in the pesticides, they must have a burst strength greater than peak operating pressure of the pump

Pressure gauges

monitor your spray system, must be accurate and have the range needed for your work

Pressure regulators

control the pressure and indirectly the quantity of spray material delivered by the nozzles, they protect pump seals, hoses, and other sprayer parts from damage

Control valves

located between the pressure regulator and the nozzles to provide positive on-off action, ones that stop all flow, or flow in any section of the spraying system, should be within easy reach of the sprayer operator

Nozzles

break liquid into droplets, distribute spray in a predetermined pattern, and help control the application rate

What has the greatest effect on drift?

Nozzles

Nozzle performance depends on:

- nozzle design or type

- size of the spray tip opening (orifice)

- operating pressure

- discharge angle

- distance between the nozzle and the target

What will increase the flow rate?

larger orifice on nozzle or increasing the pressure

Relationship between flow rate and pressure

to double the flow rate, you must increase the pressure four times

Four major parts of the nozzle

nozzle body, strainer (screen), cap, and tip or orifice plate

they may include a spinner plate

Three types of nozzles

solid stream, fan, and cone

Special purpose nozzle tip patterns

raindrop, flooding, and wide-angle fan or cone-shaped

What tips are better for contact insecticides

cone tips because they offer better penetration of foliage rather than fan tips

Nozzles that are most resistant to abrasion and corrosion

tungsten carbide and ceramic

Stainless steel tips

resist corrosion and abrasion, especially if they are hardened, moderately priced

Brass tips

resist most corrosion (except from fertilizers and WP) but do not resist abrasion

Nylon tips

will not corrode but may swell when exposed to some organic solvents, and wears out like brass

Aluminum tips

inexpensive and resist some corrosive materials, but wear out quickly

Spray monitors

help detect system errors or failure, some sense the flow at each nozzle

System monitors

sense operating conditions of the total spraying system

Sensors and microcomputer

provide information on travel speed, pressure, line flow, application rates, acres, and gallons to empty

if something goes wrong or if the flow changes an alarm sounds

Controlled droplet applicators (aka rotary spray nozzles)

have a spinning with small grooves that spiral up the inner wall, the nozzles are gravity fed from the spray tank and are powered by small electric motors

uses centrifugal force

Hydraulic sprayers

makes spot, band, or broadcast treatments

water is the most frequently used carrier

Low-pressure sprayers

psi of 15-80, does not deliver sufficient volume to provide adequate coverage to some insecticides and fungicides

cannot penetrate dense foliage

used on large turf areas such as golf courses

Small-capacity sprayers

hand or backpack, treat individual plants, small areas or hard to reach areas, uses compressed air, holds 0.5-5 gallons

Granular spreaders

most common are drop (gravity) and rotary which contain three main parts: hopper, mechanical agitator, and some type of metering device

Hopper

holds the pesticide

Mechanical agitator

at the base of the hopper to provide a uniform and continuous feed

Metering device

usually a slit gate to regulate the flow of granules

Drop spreaders

apply course, uniformly sized particles to soil, water, and sometimes foliage

a revolving agitator activates when the spreader is in motion for uniform dispensing

Drop spreaders advantages

generally more precise and deliver a better pattern than rotary spreaders

minimal chemical drift and good control, little chance of applying to nontarget areas

some can shut off one side to edge driveways or sidewalks

Drop spreader disadvantages

the edge of a drop spreader is sharp so any steering error will cause strips to either be missed or doubled

the amount of material flowing from the spreader does not change proportionally with changes in speed

uniform distribution can be difficult to achieve

some won't handle large granules

don't apply to foliage well

Rotary spreaders

distribute granules to the front and sides of the spreader, usually by means of a spinning disc or fan

power and hand-driven models

most produce a swath width of 6-8 feet

Rotary spreader advantages

they cover area faster than drop spreaders

easy to push

not as easily knocked out of calibration

Rotary spreader disadvantages

less precise in uniformity and distribution than drop spreaders

more sensitive to ground speed, physical characteristics of the granules (size & shape), and environmental factors (wind, temp, humidity)

faster ground speed throws granules further and faster

Three steps to take to be sure you are applying the right amount of pesticide:

1) calculate the size of the target area

2) use the label directions to calculate the amount of pesticide you need to apply

3) calibrate your application equipment

Four steps to prepare equipment for calibration

1) sprayer nozzle tips are correct for the application

2) clean and inspect all nozzles, nozzle tips, and screens, use a soft brush, not wire, add water to the spray tank and watch the nozzle output, if distorted, discard

3) check all the pressure gauges, if rusty or inaccurate, replace

4) check spray volume output of all nozzles, if one differs by more than 5%, replace, if one varies seriously from the average, may need to replace all nozzles

Sprayer calibration accounts for

speed, nozzles, pressure, and spray width

Relationship between spray application rate and sprayer's travel speed

inverse relationship, doubling the ground speed will reduce the application rate by 1/2

Lawn gun distribution

determined by the walking speed and the gun motion used by the applicator

Lawn gun use

a swath of 8-10 feet is best, try to hit each point 2-3 times to ensure good coverage, at least 1 foot of overlap between swaths is needed to avoid skips in coverage

Phytotoxicity

plant damage resulting from a pesticide application to a desirable plant, some signs are burnt leaves, flowers, or growing tips, yellowing, leaf distortions, abnormal growth, and stunting

sulfur based pesticides combined with ____ cause increased injury

oils

Phytotoxicity can be avoided by:

- avoiding use of pesticides on plants known to be susceptible

- using formulations that have reduced phytotoxicity hazard

- applying pesticides under the best environmental conditions

- following label directions on application rates or frequencies

- avoiding pesticide mixtures

- never using equipment that has been used for herbicides to apply insecticides or fungicides

Check valves

prevent dripping when flow to the nozzle drops below a certain pressure

Strainer mesh sizes

described by the number of openings per linear inch; a high number indicates a fine screen

Strainer locations

filler opening, suction or supply line to pump, between pressure relief valve and the boom, and on the nozzle body, strainer mesh should be progressively smaller

Choosing a hose

weather-resistant and has burst strength greater than peak operating pressure of sprayer, synthetic rubber or plastic that resists oil and solvents in the pesticides

Nozzle height

distance between nozzle tip and the target

Boom height

affects the uniformity of the spray pattern especially important in broadcast application

Why can you never allow a pump to run dry or have restricted inlet or outlet?

pumps depend on the spray liquid for lubrication and removal of friction heat, pumps will be damaged

Rinsate

water and sometimes solids contaminated with pesticide, sourced from washdown water from cleaning equipment or mixing and loading pad

use this to spray target site and reduce generation and concentrations of wastes at clean-up area

Proper preparation for storage of pesticide sprayer

add 1-5 gallons of lightweight emulsifiable oil to equal amount of clean water, pump the mixture through, the oil leaves a protective coating

remove, clean, and place all nozzles and screens in a dry place to prevent corrosion

cover nozzle openings with tape to keep dirt out