A SCOUT'S GUIDE TO BASIC COTTON TERMINOLOGY

J. S. Bacheler
Department of Entomology
North Carolina State University

DRAFT 5/30/94


adulticide - A chemical, usually an insecticide, which is targeted toward the adult stage.

aphicide - An insecticide which is active against aphids.

beet armyworm - An armyworm species characterized by cotton leaf skeletonizing by early instar feeding in groups, often associated with webbing and frass. Later instar larvae may feed upon squares and bolls and are difficult to control with insecticides; eggs deposited in masses; adults migratory, do not overwinter in the Carolinas.

beneficial arthropods - A general group of insects and their cousins (predatory mites and spiders) which either consume (predator) or live within (parasite) the host insect.

bloom - These large, showy, off-white flowers arising from buds (squares) typically last only one day, becoming pinkish in the second and brown on subsequent days, usually falling from the new developing boll on days 3-5. Cotton blooms are at times attractive sites for bollworm egg deposition, western flower and other thrips and fall armyworms. Blooms in the tops of cotton plants ("blooming out the top" or "bumblebee cotton") often indicate very dry weather or the cutting out of the crop.

bloom tag - The sticking of the dried brown cotton bloom onto the tip (or at times off to one side) of the young boll; more frequent in dry weather; sometimes provides a refuge under which young bollworms or tobacco budworms develop protected from beneficial insects and insecticides. Untrained scouts sometimes have a tendency to oversample young bolls having a bloom tag. The sampling of bloom-tagged bolls should be carried out in proportion to their percentage of the total boll population.

beat cloth - A square (typically 3 ft. by 3 ft.) or rectangular piece of usually light-colored cloth or synthetic sheeting (i.e., Tyvik material) with a dowel at opposite ends; used to assess insect populations by beating or shaking plants onto the device which is normally unrolled and placed on the ground between rows. Also called a shake cloth.

blooming out the top - A cotton growth state characterized by presence of first position blooms almost entirely in the upper canopy of cotton plant. This occurrence may indicate premature cutout of the crop. Often called "bumblebee cotton" when this event occurs abnormally early on short, stressed cotton.

boll weevil - A small brownish to grayish weevil which survives the winter as an adult and invades cotton in the spring to infest 1/3 or more grown cotton squares, causing fruit abortion via feeding or egg punctures; completes life cycle within fallen squares in 2 to 3 weeks. A major pest of cotton in North Carolina prior to the beginning of the Boll Weevil Eradication Program in 1978. May undergo 3-4 generations per year in the Carolinas.

bollworm - The larval or caterpillar stage of the corn earworm moth. Typically North Carolina's most significant cotton pest, primarily infesting fruit (squares, blooms and bolls). Undergoes 3-4 generations annually in the Carolinas, with the first two developing primarily in field corn and the third on cotton, soybean, peanut and other crops. Also called soybean podworm and tomato fruitworm, depending upon host.

bract - The three modified leaves subtending the cotton fruit. Bracts typically surround developing squares, affording some protection to bollworms and others pests from beneficial insects and insecticides; must be opened to reveal developing square when monitoring fruit for damage.

calyx - Outer protective covering of the flower bud (square), the leaf-like green segment also called sepals.

canopy - The foliage of a cotton crop; said to be closed when plant growth of adjacent rows closes over and shades row middles; direct sunlight penetration between rows constitutes an opened canopy.

carbamates - A class of chemicals, usually insecticides, which inhibits cholinesterase resulting in unregulated nerve ending activation and paralysis in insects (e.g., Temik, Sevin, Larvin).

carpal wall - The thick outer walls of the boll. If penetrated by insects (e.g., bollworms, green stink bug), may result in damage to locks, translating into lost yield and/or lower lint quality.

caterpillar - The immature damaging stage of a butterfly or moth. Larva is general term for immature stages of moths (caterpillars), flies (maggots), beetles (grubs) and others.

consultant - An individual, licensed by the North Carolina Department of Agricuture, trained to interpret information and make recommendations.

cotton aphid - Aphid species, Aphis gossipeii, most commonly associated with outbreaks on cotton in the Southeast; has many generations per year and is often resistant to various classes of insecticides; typically subject to heavy mortality via predation and parasitism; also called the melon aphid.

cotyledon - In dicotyledonous plant species, the initial growth stage characterized by the presence of "seed leaves." These leaves initially contained in the seed and provide food for seed germination.

cut-out (cutting out, cutout) - Final stage of cotton plant growth prior to boll opening and characterized by predominance of more mature fruit, general absence of squares and blooms and cessation of new terminal growth. According to more recent terminology, cotton is approaching cut-out at five nodes above white bloom and is generally considered to be cut-out at three nodes above white bloom. Cotton blooming out the top is considered cut-out.

defoliant - A harvest-aid material applied to the cotton plant to accelerate leaf drop in preparation for harvest (see defoliation).

defoliation - A term used to describe the loss of leaves from the cotton plant; may be damaging and happen prematurely (i.e., soybean loopers consuming cotton plant leaves prior to cut-out) or naturally (the predictable loss of leaves of all deciduous plants)

egg - A single cell or ovum from an ovary; the first stage of the insect or mite; may be deposited singly (e.g., bollworm) or in a mass (e.g., European corn borer).

European corn borer - A recent pest of cotton in the Southeast, this boring caterpillar undergoes its initial two generations on corn, potatoes and various weed species; the third and a partial fourth generation can be damaging to cotton, primarily via boring into medium to large bolls and to a lesser extent into stems; female moths deposit small, fish scale-like egg masses deep within the plant canopy on the undersides of cotton leaves; egg masses difficult to find; Ostrinia nubilalis.

fall armyworm - A migratory species which does not overwinter in the Carolinas; larval hatch from egg masses often deposited in the upper third of the cotton often on the undersides of leaves but also in the terminal area; small larvae typically etch the bracts of medium and large bolls prior to penetrating the carpal walls, often at the base of the boll; medium to large established larvae difficult to kill with insecticides; Spodoptera exigua.

foliar feeding - 1. On cotton, leaf consumption usually by caterpillars; 2. The feeding of nutrients, such as nitrogen-containing fertilizer, to the cotton plant via a liquid applied to the foliage.

frass - A term applied to insect feces, the shape of which is sometimes used in family- or species-level identification; also called fecal pellets or droppings.

fruit - Refers to cotton squares (or flower bud), blooms and bolls; reproductive part of plant. Cotton fruit is susceptible to a wide range of insect pests.

fruiting branch - Lateral branch of a cotton plant, typically arising from the fourth through eighth node, characterized by a fruit position at each node; sympodium.

fruiting position - Any main stem, vegetative branch or fruiting branch location on which fruit is either present or aborted.

fungicide - A material which is used to control or kill fungi.

green stink bug - A large green member of the true stink bug family (Pentatonidae) which usually undergoes a generation on wild hosts, such as elderberry and wild cherry, prior to moving into cotton often during boll formation. Feeding by adults and large nymphs with needle-like stylets, often on bolls of all sizes, causes small rounded dark spots on exterior carpal wall; can transmit hardlock organism by feeding, resulting in unharvestable bolls and low quality lint, Acrosternum hilare.

herbicide - A material used to kill weeds; in cotton usually characterized by timing: "PPI" - prior to planting and incorporated, "pre" - prior to plant emergence from soil, and "post" - after plant emergence, or by application type: "broadcast" - applied evenly over an area, "banded" - applied over a portion of total area, or "directed" - targeted at a specific area, usually toward the base of the cotton plant.

insect growth regulator - A compound, either natural or synthetic, which influences insect growth and development (e.g., Dimilin affects boll weevil grub integument formation during shed, resulting in deformed pupae and adults or premature death.)

insecticide - A material which kills insects because of its toxicity.

instar - State of nymph (e.g., stink bug) or larva (e.g., bollworm) between molts.

internode - The portion of the stem between nodes; in cotton often used as an indicator of growth, i.e., a greater internode length indicates more rapid growth and possible need of a growth regulator such as Pix.

label - A legally binding document affixed to all pesticide containers outlining the product's constituents, amount of active ingredients, primary uses, precautions, and worker protection safety standard (WPS) information.

larva - The immature stage of an insect which has four distinct metamorphic stages (e.g., cabbage looper: egg, larva [caterpillar], pupa and adult).

larvicide - A compound which kills the larval stage of insects.

layby - A final, typically post-directed, herbicide application designed to eliminate or suppress weeds through harvest.

light trap - A device consisting of at least an ultraviolet light (which is attractive to a number of night-flying insects) and a collection container. Utilized to monitor the timing and relative abundance of selected insect species (e.g., bollworm and European corn borer).

matchhead square - Early stage of growth when the bud (excluding the outer bracts) reaches approximately the size of a large kitchen match head.

migratory - A term applied to insect species which undergo long range (sometimes hundreds of miles) movement (e.g., fall armyworms do not overwinter in the Carolinas but rely instead on annual long range northward movement by consecutive generations "hopscotching" from southern United States).

mites - A group of small, active, non-insect arthropods, some of which are predators of other mites and small insects (e.g., thrips); most species are plant feeding. The twospotted spider mite (Tetranicus urticae), typically more of a problem under hot, dry conditions and damaging cotton plants by rasping mostly lower leaf cells, is the predominant mite on cotton in the Southeast; populations often reduced by naturally- occurring fungi, particularly under humid conditions.

miticide - A material which kills mites.

node - Points, usually along the main stem, at which lateral vegetative and fruiting branches arise.

node above white bloom - Term applied to the number of nodes from the last developed white bloom to the plant terminal; used as a measure of plant growth (e.g., to assist in growth regulator assessments or as an index of degree of "cutout").

organophosphates - A class of organic, phosphorus-containing insecticides which inhibit cholinesterase causing excess nerve activation, paralysis and eventual death; some insecticides in this class with a high phosphorus content (e.g., methyl parathion) may delay cotton crop maturity if applied at an early stage; abbreviated OP.

ovicide - A material which kills the egg stage of an organism.

parasite - An organism which lives wholly off of and often feeds within another (called a host); with most insect species, insect parasites usually kill their host and are referred to as parasitoids.

pheromone trap - A trap which utilizes either a natural or, more typically, a synthetic insect sex attractant pheromone; these traps are usually species specific.

pinhead square - In practice this misnomer most often applies to matchhead squares.

plant bugs - Small, active, dark brown bugs with piercing-sucking mouthparts; insert tiny needle-like holes into small squares causing darkening and abortion; at high population levels terminal feeding may result in unusual upper growth (crazy cotton) and loss of apical dominance.

plant growth regulator - A substance applied to cotton plants which affects growth or senescence (e.g., Pix and Prep); abbreviated PGR.

plant map - A precise prescribed manner of recording, or mapping, cotton plant growth which shows the location and stage of fruit by its position on each node of all vegetative and fruiting branches. Plant maps are often used to determine nodes above white bloom, nodes above cracked boll, fruit retention and to compartmentalize and compare fruit retention on selected horizontal or vertical zones of the cotton plant. Modified mapping systems are available which focus on particular vertical zones of cotton such as first position only.

point sampling - A scouting method which relies upon randomly selecting a prescribed number of sites or points within a cotton field for intensive scouting of a predetermined number of plants or feet of row (best suited for uniform fields).

postemergence directed - Herbicide placement after seedling emergence directed to the base of cotton plants; better control if cotton has achieved a significant height differential over weeds (e.g., Bladex).

postemergence over the top - Herbicides applied directly over the canopy of both cotton and weeds; sometimes represents a salvage treatment following inadequate PPI or pre- emergence weed control; some compounds may cause maturity delays and yield reductions (e.g., Cotoran).

predator - An organism which kills and consumes another (its prey); a number of mostly small predator insects can provide significant natural control of several pests.

preemergence - A term most often referring to broadleaf herbicides applied at or after planting but prior to seedling emergence; "pre" herbicides (e.g., Zorial).

preplant incorporated - Refers mostly to grass and small seeded broadleaf herbicides (but also some other weed species such as nutsedge) applied and incorporated prior to planting; PPI herbicides (e.g., Treflan).

pupa - The compact, often protected, resting stage of an insect preceding the adult stage (bollworms overwinter in the pupal stage under the soil surface).

pyrethroids - A class of insecticides characterized by very low mammalian toxicity and high insect activity at low usage rates.

random sampling - A scouting method which relies upon continuous inspections throughout most of a cotton field; better suited for regions with variable soils within fields.

rank - A term signifying tall, vegetative cotton growth; often a result of late planting, excessive nitrogen fertilizer, fertile soils and/or excessive moisture; rank growth often renders cotton plants more attractive and susceptible to late season insects, more susceptible to bollrot and more difficult to defoliate.

restricted entry interval - The mandatory period of time between application of a chemical and entry to the treated area.

sample - The portion of a population collected in a prescribed manner upon which a judgment is made about the entire population.

scout - An individual trained to collect information about cotton insect and plant populations; scouts are not responsible for interpreting data or providing recommendations.

scouting - The procedures followed by a scout.

skeletonizing - A type of insect damage characterized by feeding upon leaf areas between veins; can result in a lacy appearance.Also called windowingpaning.

soybean looper - A light green, defoliating caterpillar whose migratory adults overwinter in the southern United States, Carribean basin and typically arrive in the Carolinas in late summer or fall; Pseudoplusia includens.

square - The flower bud of a cotton plant with a central corolla containing the pollen anthers and sepals and surrounded by three (or sometimes four) bracts (squares are often the preferred site of insect damage; e.g., plants bugs, boll weevils, bollworms).

square retention - The proportion of squares, usually expressed as a percentage, retained by the cotton plant (often employed early in the growth of a cotton plant as an index of plant development).

starter fertilizer - Fertilizer placed in close proximity to the seed, usually at planting; also called pop-up fertilizer.

sweep net - A sturdy net composed of a 15-inch (standard size) rigid wire support and a heavy duty cloth bag used to "sweep" across the upper canopy of cotton plants to assess insect populations.

systemic - Taken up through the roots or leaf tissues into the cells of the cotton plant (as opposed to remaining on the surface), often in concentrations high enough to affect a biological change (e.g., at planting soil insecticides taken up by cotton seeding roots and transported through the plant's vascular system to suppress or kill leaf-feeding thrips or Roundup herbicide absorbed into the vascular system of weeds and translocated to the root zone in high enough concentrations to kill the weed).

terminal - The dominant, upper mainstem part of a cotton plant containing 3-4 expanding leaves and developing squares; if they are all retained, the number of squares typically is identical to the number of leaves; apex.

threshold - The point at which an action is taken; often applied to insects; (most are action thresholds - an action is taken when a level of eggs or caterpillars is reached; or can also be an economic threshold, which takes the commodity and treament cost into consideration).

thrips - Tiny, active insects of the order Thysanoptera which primarily move into seedling cotton in high numbers, often as a result of drying alternative hosts.

tobacco budworm - A caterpillar pest of primarily squares and bolls; close relative of the corn earworm; undergoes 3-4 generations annually; often predominant species of bollworm/budworm complex in June in the Carolinas; mid-South populations of tobacco budworms have developed resistance to all major classes of insecticides.

vegetative branch - Lateral branch on a cotton plant which does not have a fruit at each node; fruiting branches, however, can develop from vegetative branches.

vegetative growth - General term for undesirable cotton plant growth typified by lack of fruit; often tall and rank.

weed map - Simple diagram, typically developed in the fall, of a field or field portion showing location of predominant economically important weeds; used in planning upcoming weed management programs.

whitefly - A small white-winged insect with piercing-sucking mouthparts; damages cotton both directly via its sap-feeding and indirectly via voiding honeydew, resulting in "sticky cotton," a ginning and milling problem.