Abiotic Quiz Module 4

Regional Locations of Air Pollution

learge cities, refineries, electric power plants, airports, highways and strets, incinerators, dumps, pulp and papper mills. coal, gas, and petrolum

What is the relation to air pollution and plants?

physiological changes in plants, lower growth and yield loss

What symptoms are most used for detecting air pollution injury?

Visible Symptoms

What is essential for a differential diagnosis compared to air pollution?

Time and Location

When is the Ozone layer not beneficial to plants?

When in wrong concentration, time or place

Ozone Injury Symptoms

species dependent, flecking(light tan irreg spots), stippling (dark pig areas), Bronzing, reddening, chlorosis, older leaves more sensitive, upper leaf surface, in between veins, necrosis

When are yields affected in relation to the ozone?

when daily average ozone concentrations react > 50 ppb

Ozone Diagnosis Confirmation

weather station data, warm season, right time and place of onset, susceptible species

Ozone Severity of Damage Dependent on

weather, length of exposure, crop, genetics,

How to fix ozone damage

avoidance, switch species or cultivars or switch seasons

Top 5 metro regions with highest O3

Los Angeles, CA, Bakersfield, CA, Visalia, CA;, Fresno, CA, Houston, TX

Indicator Plants

sensitive crops and landscape plants that show symptoms from long term exposure to air pollution

Sentinel Plants

sensitive crops and landscape plants that show well defined air pollution symptoms exposed for shorter time periods

Ethylene Injury to Crops

abscission of leaves flowers and fruits, functions in the normal maturation process, shoot elongation, lateral growth, dormancy, premature senescence

How to detect ethylene

greenhouse sensors, Co>50 ppm in flue gas can,

Ethylene Symptoms

Epinasty (downward leaf curl), seedling leaf epinastiy, chlorosis

Sources of Ethylene

incomplete combustion or leaky combustion line, Malfunctioning greenhouse heater or poorly vented flu gas, Greenhouse CO2 generator malfunction, Propane forklift in greenhouse, Floral & produce handling in storage, Drift from neighboring field application

PAN (Peroxyacetyl nitrate ) Sources

secondary pollutants, any fossil fuel combustion, lighting, motor vehicle exhaust, biomass burning

PANs symtptoms

silvering on lower leaf, glazed/bronzed appearance, younger leaves affected, first fully expanded leaves may be more susceptible

What Precise PAN symptoms are there?

species, tissue maturity, concentrations, duration of exposure, light regime

Sulfer Dioxide symptoms

orange-red to brown; chronic injury appears white, tan, or light gray, Often interveinal; nearby veins/tissue may remain green, Highly variable by species, leaf age, season, and weather, Show streaks, tip blight, or blotches, Affects both sides of the leaf (bifacial), spreads to margins

Fluoride Sources

Natural component of soil, plants, animals, and water, Harmful in excess, Byproduct of outdated aluminum industry, Released during phosphate mining/processing,Emitted as hydrogen fluoride (corrosive gas that dissolves in water)

Fluoride Symptoms

Affects younger leaves; dark band may separate dead (brown) and healthy (green) tissue,In conifers, tip dieback: chlorosis → reddish-brown necrosis,Fluoride gas enters via stomata, accumulates at margins causing necrosis, Symptoms may be delayed in cool temperatures, Common near manufacturing areas; less frequent with improved air quality

How does Vapor drift occur?

airborne movement of a pesticide as a gas, more dependent on properties of herbicide or pesticide, evenly distrubuted

What environmental factors contribute to vapor drift?

Air temperature, vapor pressure, soil moisture, topography, dry soil, pesticide formulation, wind speed and direction, temperature inversions→ trapped vapors near the ground

How does particle drift happen? (Soil-borne)

airborne movement of spray droplets during application, most common, more dependent on properties of the sprayer and operator, soil-borne particle drift- dust, visible, unevenly distributed

How can injury be caused by proper use of pesticides?

Intermittent occurrences difficult to anticipate, no problems=instructions are overly cautious, phytotoxic interactions

How does the use of Captan 50 fungicide result in phytotoxicity?

induced leaf spotting, 2-3 leaves on each terminal, 5-10 days for injury to be visible

Categories of Pesticide Phytotoxicity Interactions

Environmental conditions, cultivar sensitivity (genetic), growth stage or age, mixing, drift, misapplication, rate error, cary over,

Growth Stage and Phytotoxicity

seedlings have delicate root systems and tissues, easily penetrated due to thin cuticules

Clomazone Injury Symptoms

yellowing of tips of leaves, intervenaial chlorosis

Spray Droplet Particle Drift- Droplet Size

controlled by spray rig parameters, size in micrometers, nozzle tip size, design and pressure,

Factors Controlled By Operator that contribute to spray droplet particle drift

droplet size, height of spray boom, boom pressure, distance from other sensitive crops, drift control adjuvants

Environmental Factors Affecting Spray Droplet particle drift

Wind speed, high temp, low temps reduce, Relative humidity, high humidity reduces, atmospheric inversions

Spray Droplet Particle Drift-Droplet Size larger

applicator might need smaller droplet size, balance between coverage, efficiency, droplet size, larger drops are heavier less likely to drift, high spray volumes, more chemical use, spotty coverage and low efficiency,

Spray Droplet Particle Drift-Droplet Size smaller

lighter and more prone to drift, use less water volume, less chemical, more complete foliage coverage, higher control efficacy

Electrostatic Sprayers

creates very small droplets, use much less pesticide and water vol, gives existing spray droplets negative charge, attracted to positive charge of leaves

Other forms of Particle Drift

pesticide adhering to dry soil and the soil becomes airborne dust, pesticide adhering to soil and being moved by water off-site

Operator Error-Missapplication

Not following label, making a mistake in math, using crop not label for treatment, tank mix reactions, slowing down results in higher application results, nozzle selection pressure and speed

Operator Error-Malfunction

Pressure regulator, incorrect nozzle selection, nozzle wear, clogged nozzles, misidentification of pest, weather

Symptoms of 2,4-D Injury

curling, twisting stems, whipping curling of leaves, stringy veins growing beyond leaf margins, stunted new growth

Pesticide Phytotoxicity and the Dicamba Dilemma

Dicamba (and 2,4-D) vapor pressure is not high, Particles prone to volatilize & re-vapor drift long AFTER application to crop Visual symptoms at extremely [low] as an auxin PGR

Pesticide Phytotoxcity-Dicambia symptoms

cupping on soybean, drift injury to non-GE crop, risk increases under warm temps

Pesticide Interaction with Environmental Conditions

temperature and its effect on volatilization, Wind and its effect on spray drift, Inversions, Rain and ability to move pesticide off target, Length of season – Need to control weeds, Surrounding land – flat? , Vegetative buffers – to minimize off site movement

Carryover

Crop injury due to active residual phytotoxic chemical agents previously applied and still present in the soil or substrate

Pesticide Phytotoxicity- Carryover Injury

check for mode of action, symp descriptions, management record, previous weather cost of single chemical analysis, bioassay to reproduce and confirm symp

Greenhouse Bioassy

Effective low cost diagnostic procedure, provide direct evidence for active residual potency, performed in support of analytical chemistry, enough soil/substrates found from same location, untreated soil/substrate

Glyphosate Injury

applied late summer previous season appears in spring, translocates in tree moves up to leaves in spring, my reaper cycle for 7 years

General Carryover Symptoms of Glypohosate

may appear ‘spotty’ areas with stunted plants with stubby roots, rule out nematode injury, rule out cold and wet soil with poor drainage, interview manager, application records

Herbicide Residue Symptoms

poor seed germination, twisted, supped and elongated leaves and misshapen fruit, some young plants die and yield reduced in mature plants

Dog Urine and Turf Damage

dead grass caused by fertilizer burn, dark ring surrounds burnt ring

Urea Fertilizer

sold and pills or granules, granule more uniform in size and better handling, more resistant to breaking down

What is Urea?

main nitrogen-containing substance in the urine of mammals formed in the liver, varies by species & hydration status, Colorless odorless solid, highly soluble in water, In water neither acidic nor alkaline, Practically non-toxic (rat LD50 = 15 g/kg)

Treatment Plans for Urea damage

nstall less susceptible plant species or sizes, Use turf cultivars know for lower injury, Water reduces the problem, Increased landscape & turf irrigation frequency/duration – “The dose makes the poison” and “Dilution is the solution”, Provision for larger pet green space

Reasons for Russet

Powdery mildew, frost damage (spring), chemical damage (foliage + fruit)

Captan

Resistance is not a concern: non-specific fungicide targeting multiple sites, Must be present on leaves and fruit in order to be effective, minimal activity on powdery mildew and C.A.R, no “kick-back” activity, Phytotoxic if penetrates cuticle and enters plant tissue

Conditions favoring Captan damage

Applications under slow drying conditions, applications following warm, rainy, windless weather, tank mixtures containing surfactant and spreader/stickers that may disrupt waxy cuticle