CCA International Exam

Equation for standard deviation

SD = Square root of sum of (x-u)²/N (x being each value, u being the mean of the data set, N is the number of data points in the population).

Low standard deviation = small variability.

High standard deviation = large variability/noise

Why inoculate legumes?

Inoculates increase N fixation in legumes.

What are warm germination tests used for?

Labeling and to estimate germination

What are cold germination tests used for?

To simulate stress

How many square feet in a 1 acre?

43,560 ft²

PLS (pure live seed in %) =

pure seed x germination x 100

1000 seeds/400 ft² = x seeds/43,560 ft²

What are coulters used for in planters?

To cut residue to open the soil for planting

What are row cleaners used for in planters?

To clear debris from seed opener

What are seed openers used for in planters?

Opens soil to place seed for uniform planting depth

What is a seeding rate?

The amount of seed needed to achieve an adequate stand

plants/acre

plants/ft² × 43,560 ft²/acre

Common broadleaves?

Soybean, canola, sunflower, field peas. Growth tip above the ground after emergence stage. G

GDD (growing degree days) =

Daily mean temp - base temp

What are short day crops?

Soybean, cotton

What are long-day crops?

Wheat, oat, barley

What are day-neutral crops?

Corn, tomato.

Description of grasses (monocots)?

Grow from an intercalary meristem at the base of internodes [grains]

Description of broad leaf plants (dicots)?

Grow from axillary buds or meristems at nodes/shoots [soybeans]

Life cycle of corn?

Seed stage, aleurone layer (protein beneath the pericarp, gives seed its color), below it is the endosperm (hard it is colorless/yellow, starch is white, dent comes from shrinking of soft endosperm as it dries).

Tassel and ear shoots begin to form at…

V6

What is Tassel (VT) stage?

Last branch of tassel is visible, before silk emerges (most susceptible to leaf damage).

At the reproductive stage, it’s very vulnerable to environmental hazards.

R1, Silking

2-3 days, silks on an ear are pollinated.

R2, Blister

Fertilized silks dry out, each kernel begins to develop + swell

R3, Milk

Kernels become yellow, 80% moisture content, often where sweet corn is picked, commercial corn is left to mature further.

R4, Dough

Thickening of kernel fluid (doughy) at 70% moisture

R5, Dent

Starch layer formed, soft endosperm begins to dry out (denting)

R6, Maturity

30-35% moisture, black layer (abscission layer)

Wheat growth and development

Kernel sends radicle out, coleoptile up, seminal root growth, initial growth like corn.

Wheat produces tillers to side to maximize amount of photosynthesis.

Next growth stage is when tiller begins to form elongated stems.

Boot stage: swelling inside stems, formation of reproductive parts.

Reproductive head emergence: Zadoks stage 5, Feekes stage 10.1

Flowering: Zadoks stage 6, Feekes stage 10.5, unlike corn, both male and female parts are on the flower.

Dicotyledon

Seeds with 2 cotyledons, “seed leaves” - food source for germinating seedling. No endosperm, cotyledon provides energy. Root is called radicle (same as monocot)

Legume growth and development as dicotyledon

Hilum (Dark spot) where seeds attach to a pod, this is where the two cotyledon would separate.

Ater separation, root down hypocotyl expands, seedling then starts forming unifoliate, then trifoliates second set and after.

What are epigeal plants?

Cotyledon lifts out of the ground, soybeans/alfalfa

What are hypogeal plants?

Cotyledons stay in place

R1, soybeans

Beginning of flower, plants have at least one flower on any node

R2, soybeans

Full flower, open flower at 2 upper nodes.

R3, soybeans

Beginning pod, pods 3/16 inch, pods in four upper nodes.

R4, soybeans

Full pod, pods ¾ inch, pods in four upper nodes.

R5, soybeans

Beginning seed, seeds at 1/8 inch, pods in four upper nodes.

R6, soybeans

Full seed

R7, soybeans

Beginning maturity

R8, soybeans

Total maturity, more yellow than green

pH is….

King of nutrient status, usually, neutral pH is most favorable for plant growth

Soil organic matter

Improves soil tilth, decomposes which releases N and P, reduces leaching of K/Ca/Mg.

Soil compaction

Compaction decreases total pore space in soil available for air and water exchange

What is diffusion?

High concentration outside root to low concentration inside root

What is mass flow?

Nutrient carried by water into root tissues

What is interception?

Roots grow in proximity and encounter nutrients

Fibrous access nutrients…

in shallow soil while tap roots access deeper nutrients.

Roots differ in how they alter soil porosity, tap roots create fewer, but larger pores, fibrous roots create a greater number of soil pores

What offers greatest erosion control?

Root systems having dense networks at soil surface.

Plants with fibrous root systems are more effective than those with tap root systems in preventing detachment.

Accuracy vs precision

Accuracy: how close a measured value is to the correct value, “validity”

Precision: how close a set of values are to each other, “clustering”

NIR imaging

Shows reflected infrared wavelengths of healthiest crop canopies and display this in bright red color. Crops that aren’t as healthy displayed in less red.

Hay harvest

Rapid dehydration = better preservation

Slow dehydration = potential yield reduction

Young, vegetative forage is higher in protein and energy

FDA GMO

Organism that has its genetic material/DNA modified using technology that involves the specific modification of DNA, including the transfer of specific DNA from one organism to another.

USDA Transgenic

Organism resulting from insertion of genetic material from another organism using recombinant DNA techniques

Economic injury level

Point where costs and benefits are equal

Economic threshold

Point where pest control costs are higher than benefits

Metamorphosis type

Simple (egg, young, adult)

Gradual (egg, naiad, adult)

Complete (egg, larva, pupa, adult)

Alternate vs alternative host

Alternate: does not replace another host, second choice.

Alternative: replaces another host

Beetles are

insects with chewing/biting parts , restricts photosynthesis

Mites are

insects with piercing/sucking parts , restricts plant nutrient flow , NO WINGS but true insect can have wings

Viruses

Protein w/DNA strand, cannot complete life cycle independently

Nematodes

Small roundworms, have stylet if parasitic to plants (hollow feeding spear)

Standing water limits….

oxygen to root zone, interrupts metabolism

As soil salinity increases…

Plant growth decline

Degree day =

Max timp + min temp/2

Heat unit accumulation =

Average temp - base insect development temp

When EIL is less than…

1, treatment is cost effective

REMEMBER EIL (economic injury level) EQUATION

C < V I D

(value of part of crop sold x injury amount x damage per injury amount)

Green lacewing

Feed on aphids/mites

Ground beetles

Hard bodied, control insects

Minute pirate bugs

1/5 inch, feed on small insects/eggs, bite humans in the fall.

Nabids (damsel bugs)

Generalist predators, feed on aphids/soft bodied insects, piercing mouthparts

What is volatility?

How easy a pesticide turns into a gas or a vapor

What is selectivity?

Selectivity of a pesticide to target the pest organism while sparing any beneficial organism

Water hardness

Some pesticides can bind with ions in hard water reducing pesticide concentration

Chemical compatibility

Some pesticides should not be mixed together or should only be mixed in a certain order, in all cases water would always be added first to spray tank.

Ground vs aerial application

Ground: less drift, cost effective for smaller areas, but compaction/slow

Aerial: large areas sprayed quickly, timely, no physical damage to crop or soil BUT more drift/costly

Photosynthesis inhibitors

Grasses, broadleaves, contact/systemic, pre or post emergence

Water by roots

Triazines, substituted ureas

Cell membrane disruptors groups 14,22

Contact herbicides, post emerge, leaf desiccation

Requires non-ionic surfactant or adjuvants.

Group 14: basagran, cobra, blazer, reflex

Group 22: gramoxone (paraquat)

Growth regulators/synthetic auxins - group 4

Broadleaf plants, not grass, foliar, post emerge.

2,4D

Pigment inhibitors, group 13/27

Pre emerge, turns new growth white.

Command, sonar, balance pro, Callisto.

Seedling root growth inhibitors

Germinating seedlings, soil applied

Dinitroanilines.

Seedling growth/shoot inhibitor - group 15

Germinating seedlings, pre emerge.

Chloroacetamides.

Lasso, Dual

ALS inhibitors, group 2

Post emerge, grasses/broadleaf.

Shortened internodes.

Imdazolines, sulfonyl ureas, triazolopyrimidines.

Pursuit, classic, canopy, first rate.

Amino acid synthesis inhibitors, group 9

Broad spectrum activity, grasses, broadleaves, post emerge, minimal soil activity.

Round up, glyphosate generic

N metabolism inhibitors, group 10

Chlorosis, broad spectrum, grasses/broadleaves

Liberty

Lipid synthesis inhibitors, group 1

Corn white flash, growing point rots

Select max (clethodim), assure II (quizalofop)

Locally systemic fungicides

Move into leaf, but not to other plant parts

Systemic fungicides

Absorbed by plant, distributed internally, prevent infection or kills pathogen inside plant. Commonly used in seed or in-furrow treatments.

Genetic traits in relation to pest management

Bt modified crop can be used in place of insecticide, newer technologies include RNAi and gene silencing

Broad spectrum herbicides such as glyphosate can control many bees.

To prevent or delay weed resistance, broad spectrum herbicides should be used some years and other herbicides other years.

What are the advantages and limitations to transgenic trait improvement?

Yield maybe lower in the absence of the pest, higher price, pests may develop resistance.

Chemical application reduced, multiple pests controlled.

Point source pollution

Specific, known containment source ; pipe or tank

Non-point source pollution

Enters from non well-defined area ; farm field or city neighborhood

To prepare pesticide

Determine rate, then concentration, then divide rate by concentration to get dosage

Pesticide characteristics and soil/water quality

Absorption by soil decreases potential for movement to groundwater and increases potential for movement by erosion.

Runoff increases potential for pesticide movement to surface water.

Nozzle characteristics

Large nozzle tips + lower pressure = bigger droplet, less drift.

Lower boom height means

Less drift

Higher viscosity

= Less droplet drift

Lower spray pressure creates

larger spray droplets which creates less drift

What are adjuvants?

Added to pesticide mixtures to help pesticide performance or mixture properties

MPH =

GPM x 5940/GPA x W