Chapter 7

Question 1

A ______ is a plant growing where it is not wanted. Therefore any plant may be a weed. Weeds present special problems in ornamental and turfgrass maintenance because herbicides, the primary management tool for weed control, must be chosen and applied with care to prevent injury to desirable plant species.

Answer 1

weed

Question 2

The _____ __ ______, or how herbicides affect and kill plants, differ. Some damage leaf cells and cause them to dry up. Others alter nutrient uptake or interfere with the plant’s ability to grow normally or conduct photosynthesis. The ___ ___ _____ usually determines how and when a herbicide is used.

Answer 2

mode of action

Question 3

__________ herbicides inhibit germination or seedling growth. They are applied to the soil surface or incorporated into the soil a week or two before weed emergence so that they are in close contact with the germinating weed seed. Some cause injury at the site of contact. Others are systemic, entering through the roots and moving upward

Answer 3

Preemergent

Question 4

________ herbicides are applied to the foliage surface of emerged weeds. Some have contact activity, killing the plan by destroying leaf and stem tissues. Thorough coverage is often necessary for good control. Others are systemic, or translocated (moved within the tissues of the plant) from leaves and other green parts to above- and below ground growing points. The rate and amount of uptake of the herbicide by the weed are affected by physical relationships between the leaf surface and herbicide, plant size and age, water stress, air temperature, humidity, and herbicide additives.

Answer 4

Postemergent

Question 5

Plants can escape toxicity if they can rapidly ______ or deactivate a herbicide. This ability is the basis whereby plants are differentially susceptible to some herbicides to which they normally are tolerant. Also, plant injury can result from misapplication, especially use of excessive rates, which overwhelms the ability of a plant to ______ or deactivate a chemical

Answer 5

degrade

Question 6

Weeds can be divided into two major categories: ________ and _____.

Answer 6

Broadleaf and Grass

Question 7

Weeds can be divided into three subcategories: ______ ______ and _____

Answer 7

winter annuals, summer annuals, and perenials

Question 8

______ ______ grow from seeds that sprout in the fall and flower in the spring.

Answer 8

Winter annuals

Question 9

_______ _______ start from seed in the spring or summer, mature, ripen seeds and die in the fall.

Answer 9

Summer annuals

Question 10

________ may produce flowers and seeds year after year.

Answer 10

Perennials

Question 11

A few weeds are ___________, producing leaves in the first year and flower heads and seeds in the second

Answer 11

Biennials

Question 12

Weeds are easiest to control when they are _______. Therefore winter annuals should be treated in the fall, summer annuals in the spring. Most perennials are easiest to control in the fall. In a turf or ornamental setting, all weed control efforts must be selective or used as a spot treatment to remove undesirable species growing near desirable ones.

Answer 12

young

Question 13

Broadleaf weed- Annual that is a juicy tissued, shallow-rooted winter annual that reproduces by seed and trailing stems that take root at the lower joints. The leaves arranged in paris on the stem, are usually eggshaped, smooth and less than 1 inch long. Lower leaves have hair stalks, upper leaves are without stalks; upper leaves are without stalks. The small flowers have five white, deeply notches petals. Germination begins in autumn and growth continues through winter. Seeds are produced in spring and early summer, then plants die.

Answer 13

Common or Annual Chickweed

Question 14

Broadleaf Weed Annual: Several species of _____ are weeds. Most are summer annuals; a few are perennials. Some are spindly, some fleshy. Most have a milky, acrid sap that can be irritating to eyes, mouth, and skin. Leaves are simple atlernate or opposite, and entire or toothed. The tiny flowers are clustered in small, cup-like structures resembling white-petaled flowers in some species. The fruit, three-lobed and three seeded, is borne on a stalk extending from the flower structure.

Answer 14

Spurges

Question 15

Broadleaf Weed Annual- Also known as winter mint, _____ is a winter annual that repoduces by seeds and stems rooting at the joints. Branching close to the ground, the stems are 4 to 16 inches tall and square. The plants are erect and have little or no hair. Leaves are opposite (two at each stem joint) and almost circular, with the edges having rounded teeth or lobes. Flowers are pink to purple, two-lipped and arranged in whorls at the base of the leaves. Growth habits are like those of chickweed.

Answer 15

Henbit

Question 16

Broadleaf Weed Annual- This weed can be a winter or summer annual or a biennial. It forms a basal rosette initially, then stems elongate and branch as the plant matures. Stems are erect, branching at the base, hairy and pink to red. Leaves, hairy on both surfaces, are alternate near the base and opposite above. Leaves are rounded, deeply divided into five to nine segments with each segment deeply lobed. Two or more light pink to pale purple flower clusters are at the tips of stems and branches. Fruit have an elongate “beak”

Answer 16

Carolina Geranium

Question 17

Broadleaf Weed Annual - This summer annual has a prostrate growth habit and is often found in heavy traffic areas. Stems form a dense mat from a small taproot. The leaves are alternate, oblong and rounded at the tip. Tiny white flowers are found where the leaf and stem join. Papery sheaths surround the steam at each node.

Answer 17

Knotweed

Question 18

Broadleaf Weed Perennial - ______ reproduces by seeds and new shoots from the roots. The stem, that arises from a long, thick, fleshy taproot, contains a milky juice. Leaves are usually oblong and more or less tapering. They vary from having no teeth to coare teeth, usually are covered with short hairs and are arranged in a basal rosette. The yellow flowers are arranged in a single head on a long, hollow stalk. It usually flowers in May and June

Answer 18

Dandelion

Question 19

Broadleaf Weed Perennial - Two species of _____ are important weeds: broadleaf and curly. Broadleaf ______ arises from a basal rosette with a single stem that may reach 4 feet in height. Lower leaves are petioled, very broad and flat with a heart-shaped base. Leaves become reddish-purple with age. All leaves have slightly wavy edges. The single, flowering stem is erect, reddish-brown and ribbed. Flowers consist of greenish sepals. Curly ____ is very similar in appearance except it can grow taller and its leaves are much narrower and having wavy curled edges.

Answer 19

Dock

Question 20

Broadleaf Weed Perennial - Has a vigorous, prostrate growth habit, and leaves that are opposite, oblong, and dark green adn covered with soft hairs. Hairy stems root where nodes touch the soil. The small, white flowers have five slightly notched petals.

Answer 20

Mousear chickweed

Question 21

Broadleaf Weed Perennial - Buckhorn and broadleaf _______ both reproduce by seed and new shoots from the roots. Buckhorn ______ produces 6 to 16 inch long stems that are leafless and bear a short, dense flower stalk at the top, 1 to 3 inches in length. Narrow leaves arise from the base of the flower stems. They are lance-shaped with several prominent, lengthwise veins. Broadleaf ______ produces 4 to 12 inch long stems with a longer flower spike (4 to 12 inches long). Leaves are broad and somewhat egg shaped with prominent veins. Both plants produce seed from June to September.

Answer 21

Plantains

Question 22

Broadleaf Weed Perennial - _______ has trifoliate leaves and stems that root at the nodes. Each leaf is composed of three leaflets that are egg-shaped. The leaflets usually have a light green or white marking close to the base and a slightly tootehd margin. Stems are prostrate and usually hairless. Rounded flower heads consist of 20 to 40 individual white flowers and are 2/3 to 3/4 inch wide

Answer 22

White Clover

Question 23

Broadleaf Weed Perennial - _______ resembles cultivated onion and reproduces by underground bulbs and above ground bulblets. Leaves are hollow, slender and round during early growth, but become grooved as the plant develops. Stems are 12 to 24 inches tall. The greenish- white to purple flowers are often replaced with bulblets. Underground bulbs can remain alive in the soil for up to five years.

Answer 23

Wild Garlic

Question 24

Broadleaf Weed Perennial - Also called common blue violet, this weed has heart-shaped leaves, purple flowers and grows two to five inches in height. Leaves arise from a basal crown, are hairless and have rounded teeh along the margins. Flowers occur on leafless stalks and have five petals.

Answer 24

Wild Violet

Question 25

Grasses Annual - ____ is a summer annual that reproduces by seed and by rooting at the lower joints of the stem. Stems are erect or arise from a creeping base and usually from mats. Three to ten finger like branches form at the top of stems, each one containing small flowers in two rows along one side of a branch. It thrives in summer, maturing and producing seed, and dies in the fall.

Answer 25

Crabgrass

Question 26

Grasses Annual - Is similiar in appearance to crabgrass, ______ has smooth, flat stems with distinctive silver or white centers. The stems are branched, arise from tufts and often form mats. Flowers and seeds are produced in two rows along one side of the two to ten finger like branches at the top of the stem. It matures and produces seed in summer and dies in the fall. Reproduction is by seed only.

Answer 26

Goosegrass

Question 27

Grass Annual - This is a winter annual that reproduces by seed. Its stems are flattened, grow in tufts and sometimes take root at the lower joints. Leaves are very soft, often a lighter green that turfgrasses. Seed heads are arranged in the shape of a pyramid. ______ ______ grows best during cool weather, It matures, produces seeds and dies in late spring or early summer. It can grow to a height of 4 to 8 inches.

Answer 27

Annual Bluegrass

Question 28

Grass Perennail - Sometimes used as turfgrass, this weed forms dense mats with spreading and branching stolons that root at the nodes. Leaves are small and smooth with a conspicous ring of white hairs at the leaf base. Flowering stems are upright and bear a terminal group of three to seven spike-like branches. ______ ________ grows best in warm, wet weather and produces seeds in summer.

Answer 28

Common Bermudagrass

Question 29

Grass Perennial - Has coarse, hairy leaves produced near the plant base on shoots that arise from a knotty base of short underground shoots (rhizomes). It grows in clumps and produces seed stalks of up to several feet in height. The seed head consists of three to six spikes that arise apart on the stem and often droop. Rhizomes have areas resembling concentric rings. Growth is rapid in warm weather. Seeds are produced in summer.

Answer 29

Dallisgrass

Question 30

Grasses Perennials - These perennials superficially resemble grasses, reproduce by seed, rhizomes and tubers. Yellow _______ more commonly found in turf in Tennessee, has stems that are yellow-green, solid and triangular. Long, slender rhizomes terminate in tubers that produce new plants

Answer 30

Purple and Yellow Nutsedge