ESTEFANIA C. SALVADOR 2/ Since the beginning of recorded history, weeds have demonstrated aggressive characteristics and growth that have interfered with human activities in many different ways accordingly, human being have exerted extensive efforts to control the growth and spread of these plants. The destruction of weeds was established as one of the original features of crop production before the dawn of recorded history. Throughout the ages, people have been forced to control weeds if their food crops were to produce acceptable yields. Weeds, unlike all other kinds of pests, are similar to the plants they injure. Domesticated plants are almost always higher - order plants. Weeds likewise are higher –order plants and, therefore, have the same general growth requirements as the plant with which they compete. A common practice is to ensure an adequate supply of nutrients and water to the crop plants. Weeds that grow adjacent to the crop plants compete with them for these basic requirements. Weed – control procedures, then must have to be done to protect the crop plants while providing control of the similar weed plants. Weed Science – is the study of weeds and their control, whether it be manual, mechanical, cultural, biological, chemical, or ecological Weeds can be found everywhere – in crops, pastures, rangeland, forest, aquatic areas, road side, along rail road, industrial sites and recreation areas and even in paved roads (minute cracks). A plant that is out of place. A plant growing where it is not wanted. An unwanted plant. A plant that interferes with the utilization of land and water resources or adversely intrudes upon human welfare A particular plants is a weed only in terms of human attitudes. 1. Life span – Annual, Biennial, Perennial 2. Growth Habits – vines, shrubs, trees 3. Habitat – Terrestial, Aquatic, Epiphytic 4. Body Texture – Herbaceous, woody 5. Gross Morphology – Grass, Sedge, Broadleaf weeds In weed control research, weeds are more conveniently classified according to their gross morphology. Members of the family Gramineae (Poaceae) which range from small, twisted, erect, or creeping annuals or perennials. Stems are called culms with well define nodes and internodes. Leaves arises alternately in two rows from the nodes composed of two parts, the leaf sheath which clasps the stem, the margins overlapping to form the tube, and the leaf blade usually thin, narrow and linear with parallel venation. At the junction of the leaf blade and the leaf sheath is often a membranous, often hairy outgrowth called the ligule. Examples: Echhinochloa crusgalli and Eleusine indica. Members of the family cyperaceae Bear a close resemblance to the grasses Can be distinguished by a thin triangular stem Absence of a ligule Fusion of leaf sheaths forming a tube around the stem Examples – Cyperus rotundus Cyperus iria belonging to the other family of Monocotyledonae and Dicotyledonae. identified by their fully expanded, broadleaf structure with netted venation Examples – Amaranthus spinosus Ipomoea triloba 1. Reduce soil erosion on abandoned land. 2. Add organic matter to the soil 3. Provide food and cover for wildlife 4. Yield useful drugs or delicacies 5. Beautify the landscape 6. Provide a reservoir of germplasm and constitute a potential source of domesticated plants 1. Compete with more beneficial vegetation for light, water and nutrients thereby reducing their yields. 2. Harbor insect pests, harmful rodents, and plant diseases. 3. Some are poisonous to livestock. 4. Some are directly noxious to man. 5.Aquatic weeds clog irrigation and drainage canals. 6.Make harvesting and other operation difficult. Non-chemical Manual method - is essentially hand weeding and may involve the use of small garden tools such as sticks, trowels or garden fork. Mechanical method - involve the use of big implements such as cultivators and rotary weeders. Cultural and Ecological Methods Biological Control Chemical Method – use of herbicides Rottboellia cochinchinensis (Lour.) W.D. Clayton Common names Ilocano – Marapagay, sagisi Tagalog – Aguingay English – Itchgrass Botanical characteristics Life span – Annual Gross morphology – grass Leaf – broad linear leaf blades; rough on both sides with irritating hairs along sheath Stem/stalk – culms are stout; 1-3 cm in height, occasionally branching Inflorescence – Raceme, spike like, contracting at the tip at maturity , breaks into hard cylindrical joints, falling with two attached spikelets Fruit – produces numerous seeds which germinate in flashes. Cylindrical caryopsis which contains in the seed Rottboellia cochinchinensis (Lour.) W.D. Clayton Trianthema portulacastrum L. Common names Ilocano – Kantataba, tabtabukol Tagalog – Toston English – Horse purselane Botanical characteristics Life span – Annual Gross morphology –broadleaf Leaf – opposite broadly ovate to almost circular with slightly wavy margins with petioles Stem/stalk – Green or purplish stem; flat, succulent, branchy. Inflorescence – solitary, sessile, white or pale pink to purple. Fruit – a capsule, with 1 awn at the tip opening around the middle, containing 6-8 sedds. Seeds are rough, reddish brown to black Trianthema portulacastrum L. Commelina benghalensis L. Common names Ilocano – Kulkulasi Tagalog – Alikbangon, likbangon English - Dayflower Botanical characteristics Life span – Annual or perennial Gross morphology – broadleaf Leaf – simple, alternate, ovate base narrowed into a tubular sheath enclosing the stem and bearing rust – colored hairs Stem/stalk – Low creeping plant or ascending to 30 cm tall, hairy or smooth Inflorescence – terminal, 3-4 blue flowers on a slender stalk Fruit – a 5-seeded capsule, seeds are black with wrinkled surface. Commelina benghalensis L. Commelina diffusa Burm. f. Common names Ilocano – Kulasi, Kulkulasi Tagalog – Tari-tari, Alikbangon English – Spreading dayflower Botanical characteristics Life span – Annual or perrenial Gross morphology – Broadleaf Leaf – alternate, lanceolate to broadly lanceolate Stem – fleshy, creeping to ascending, heavily branched Inflorescence – subtended by a folded leaf like bract 2-3 cm long petals blue Fruit – 3 celled capsule with 3 seeds Commelina diffusa Burm. f. Cyperus rotundus L. Common names Ilocano – Barsanga, balisanga Tagalog – Mutha English – Purple nutsedge Botanical characteristics Life span – Perennial Gross morphology – Sedge Leaf – linear, dark green 5-20 cm long or sometimes as long as the stems, peppery odor when base leaves are crushed Stem/stalk – Single, erect 3 angled stems with wiry rhizomes Inflorescence – terminal umbrella – like, simple or compound, spike dense or loose, with 3-8 reddish spikelets Fruit – an achene, ovate or oblong-ovate 3 angled, blackish when ripe Cyperus rotundus L. Amaranthus spinosus L. Common names Ilocano – Kalunai, Kuantong Tagalog – Kulitis, oray English – Spiny amaranth Botanical characteristics Life span – Annual Gross morphology – broadleaf Leaf – simple, alternate, ovate to broadly lanceolate Stem/stalk – Stout, often reddish, erect and branched herb, with slender, sharp-pointed spines on axils of the leaves Inflorescence – terminal that are green or greenish white Fruit – a one seeded dehiscent capsule with shiny, black, lensshaped seeds. Amaranthus spinosus L. Echinochloa colona (L.) Link Common names Ilocano – Dakayang, Dakayon Tagalog – Bulang, Pulang -puwit English – Jungle rice Botanical characteristics Life span – Annual or perennial Gross morphology – grass Leaf – sheath smooth or hairy at the nodes; basal portion often tinged with red; blade smooth, linear lanceolate Stem/stalk – Erect or trailing in appearance with culms. Rooting takes place in the lower nodes. Inflorescence – a terminal panicle, green to purplish with short compact branches. Spikelets ovate to broad ovate Fruit – a caryopsis, elliptical Echinochloa colona (L.) Link Ipomoea triloba L. Common names Ilocano – Marakamote, kamkamote Tagalog – Kamo-kamotihan English – Three-lobe morning glory Botanical characteristics Life span – Annual Gross morphology – broadleaf Leaf – ovate, basally chordate, sharp – pointed and tapering at the tips Stem/stalk – Herbaceous with milky sap, crawling or twining vine Inflorescence – flowering year round, pink to purple in color Fruit – a spherical, hairy capsule Ipomoea triloba L. Eleusine indica (L) Gaertn. Common names Ilocano – Labba-labba, sabung-sabungan Tagalog – Kabit-kabit English – Goosegrass Botanical characteristics Life span – Annual or perennial Gross morphology – grass Leaf – linear leaf blades, with a few white hairs scattered on the upper surface, sheath strongly compressed – keeled, ligule membranous Stem/stalk – culms are strongly compressed, usually erect and slender. Inflorescence – flowering culms, racemes long, appearing from the apex of the culm. awnless Fruit – a caryopsis, grains or seeds is reddish brown with conspicuous ridges Eleusine indica (L) Gaertn. Ageratum conyzoids L. Common names Ilocano – Bangbangsit, marakalding Tagalog – Bulak-manok, damong mabaho English – Tropic ageratum Botanical characteristics Life span – Annual Gross morphology – broadleaf Leaves – simple, opposite, broadened toward base with serrated margins Stem/stalk – Erect, branched and somewhat odorous herb; growing upto 60 cm high with rigid and stiff hairs on stem Inflorescence – flowers corymb, branched with clusters of 4-18 flower heads colored white, violet or pale blue Fruit – a slender, lanceolate, pentagonal, black achene Ageratum conyzoids L. Cleome rutidosperma D.C. Common names Ilocano – Tantandok Tagalog – Sili-silihan English – Spindle top Botanical characteristics Life span – Annual Gross morphology – broadleaf Leaf – petioles are 2-5 cm long, with 3 leaflet, ovate to oblong, narrow, tapering at each end, central leaflet longer than the others. Stem/stalk – Erect and branchy; angular with sparse, stiff hairs, basal portions of branches purple Inflorescence – flowers, 1-1.5 cm in diameter, solitary in the axils of the upper leaves, on slender stalk, colored lilac to pink. Fruit – capsules pointed at the tip, splitting from below into two valves seeds are dark brown traversely ridged. Cleome rutidosperma D.C. Mimosa invisa Mart. Common names Ilocano – Gamusa Tagalog – Makahiya, makahigang lalaki English – Giant sensitive plant Botanical characteristics Life span – perennial Gross morphology – broadleaf Leaf – alternate, about 10-20 cm long, petioled and bipinnate, leaflets are oblong- linear, many pairs smooth on both sides, fringed with hairs. Stem/stalk – Herbaceous, slightly woody stems, prostrate. Angular branches with abundance prickles bent outward or backwards. Inflorescence – talked umbels of radially symmetrical pink flowers. Fruit – flat, oblong pod, hairy and splitting traversely, seeds are flat, yellow brown. Mimosa invisa Mart. Cynodon dactylon (L.) Pers. Common names Ilocano – Bakbaka, galot-galot Tagalog –Kawad-kawad English – Bermuda grass Botanical characteristics Life span – perennial Gross morphology – grass Leaf – small, linear, lance-shaped blue green smooth on the lower surface, hairy on the upper, margins rough. Ligule is membranoushairy, sheaths on aerial stem. Stem/stalk – Erect or trailing culm on the ground, slender, smooth green to reddish Inflorescence – consist of severalslender spikelets, sessile, flattened. Closely overlapping in 2 rows along one side of the spikes. Fruit – a caryopsis, flattened, elliptical reddish brown. Cynodon dactylon (L.) Pers. Calopogonium muconoides Desv. Common names Ilocano – Kalopogonium Tagalog – Balatong aso English – Calopo Botanical characteristics Life span – perennial Gross morphology – broadleaf Leaves – alternate and trifoliate, with leaflets 3-13 cm long, hairy on the both side, oval or elliptical or somewhat diamond-shaped or round. Stem/stalk – Creeping, up to 3m long, succulent with brown rough hairs, with strong twining tendency Inflorescence – axillary, short to long stalked headlike to racememose; flowers few covered with brown hairs, small and pale blue Fruit – a linear pod, straight or curved densely covered with brown hair, dehiscent, containing 5-8 seeds. Seeds are yellowish or brownish red Calopogonium muconoides Desv.
