Weed . identification. Technology subject

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1. IDENTIFICATION OF WEEDS Practical - 06

2. What is weed? A weed, by definition, is a plant growing where it isn’t wanted. This generally means they are in direct competition with growth of desirable plant. Classification of weeds by their life cycle Annual Species Biennial Species Perennial Species

3. Annual Species Annual plants complete their lifecycle in  one year (one growing season) These are often rapidly spreading and germinate quickly. They germinate, grow, bear flowers and fruits and die off in same year.

4. Biennial Species Biennial species  take two full years to complete their life cycle. They germinate grow leaves and stems in first year, in second year they bear the flowers and fruits. Perennial Species Perennial weeds  produce long taproots that make them difficult to eradicate. These plants come back year after year from the same root.

5. Computation of yield losses due to weeds Percentage reduction in yield- Measure of efficacy of a particular treatment when compared with weed free treatment and is expressed as percentage reduction in yield. Higher in % yield reduction means greater loss due to weeds

6. Computation of yield losses due to weeds Percentage reduction in yield = Where, X is yield from weed free plot and Y is yield from treated plot Problem- A weed free plot of Sorghum has given yield of 1500 kg ha-1 whereas atrazine have given yields of 1400 kg. Calculate the % yield reduction? X – Y x 100 X

7. Biology of important weeds

8. Acalypha indica (Copperleaf ) Type : - Annual weeds Size :- It can grow up to 1.2 m tall in favorable circumstances but is usually all smaller . Habitat :- Waste land, Rode sides , Forest edges Appearances :- The leaves base is rounded to shortly attenuate .The flower spikes are axillary 2.5-6 cm long. Tiny male flowers are white green color located on upper part of flower spikes. Green female flowers are located lower on the spikes. Uses - The weed has tradition medicinal uses.

9. How to control it: Hand weeding , mowing Use integrated weed management (IWM)  Use selective herbicide that target broad leaf weeds without harming crops Ex- 2-4 D , glyphosate Use pre emergent herbicides Continue……..

10. Parthenium weeds ( Parthenium hysterophorus ) Type :- Perennial crop Habitat :- Semi arid, subtropical , tropical and warmer temperate region Size :- Usually grows 0.5-1.5 m. Appearances :- Matures stem is greenish and longitudinally grooved covered in small stiff hairs. Numerous small flowers heads are arranged in cluster. Flower heads are white or cream color and have 5 tingly petals.

11. How to control it: Chemical control young and actively growing eg :- 2-4D , paraquat , glyphosate seedling and mature plant eg :- Dicamba   Continue……..

12. Tick berry ( Lantana camara ) Type :- perennial Habitat :- Tropical and sub tropical countries , forest margins Size :- Shrub which typically grows to around 2 m tall Appearances :- leaves are broadly ovate . Have strong odor , small tubular shaped flowers which have 4 petals and arrange in cluster, flower in many different color (red, yellow ,pink, white and orange), fruit is a berry like drupe which turns from green to dark purple. How to control it: Mechanical control by slashing plants. Grow the shade tolerates crops - lantana camera prefers sunny areas

13. Spreading hog weed ( Boerhavia diffusa ) Type :- Perennial Habitat :- Tropical area Size :- Usually grows 5 to 6 cm Appearances :- Characterized by cotyledons and its opposite leaves of different size, Flowers are small, around 5 mm in diameter. stem purplish or reddish, thickened at nodes. Uses :- used as a fodder for livestock

14. How to control it: Mulching Tillage Use Selective herbicides (MCPA and 2-4D ) Do the crop rotation Continue……..

15. Coat buttons ( Tridax procumbens ) Type :- Annual to Perennial Habitat :- Tropical and sub tropical area Size :- Usually grows 2 feet Appearances The plant bears daisy-like yellow-centered white or yellow flowers with three-toothed ray florets. The leaves are toothed and generally arrowhead-shaped.

16. How to control it:-  Use a mulch or a pre-emergent herbicide in spring to prevent quick weed. These plants have a shallow root system and are easy to pull by hand or spot-treat with a post-emergent herbicide. Continue……..

17. Type :-  Grass-like perennial Size :-  2 feet tall, 1 foot wide Habitat :-  Lawn, landscape, or garden areas in sun or shade Appearance :-   Nutsedge has slender, grassy leaves, triangular stems , and small, nutlike tubers on the root system. When these weeds pop up in lawns, they often grow faster than turf grass, so they are easy to spot. Nutsedge ( Cyperus rotundus )

18. How to control it: - Remove these plants as soon as you've identified them. Do not allow them to develop tubers. Tubers develop about four to six weeks after the shoot. Crop rotation Proper irrigation method Use selective herbicides that specifically target weed without harming the main crop Continue……..

19. Dandelion ( Taraxacum   officinale ) Type:  Broadleaf perennial Size:  12 inches tall, 6-16 inches wide Habitat:  Lawns and gardens in sun or shade Appearance:  This common lawn weed  has a long taproot  with deeply notched leaves. Yellow flowers mature into puffballs. Dandelion seeds are like parachutes that fly away in the wind, helping them invade new spaces in lawns and garden beds.

20. How to control it : - Dig up the roots with spade Mulching with landscape fabrics You can use herbicide to eliminate dandelions Continue……..

21. Crabgrass ( Digitaria   spp ) Type:-  Grassy annual Size:-  Up to 18 inches tall and 20 inches wide Habitat:-  Lawn, landscape, and garden areas in sun or shade Appearance:-  Crabgrass is exactly what it sounds like: A grassy weed. This lawn weed grows roots anywhere the stem makes soil contact. Seed heads spread out like four fingers.

22. How to control it:   Control by mulching , hoeing, and hand pulling when the plants are young and before they set seed. Can control this weed with solarization Apply pre emergent herbicides. ( Before seeds are germinates) Continue……..

23. Purslane ( Portulaca  oleracea ) Type:-  Broadleaf annual Size:-  Up to 6 inches tall and 2 feet wide Habitat:-  Dry, sunny landscape and garden areas Appearance:-  Identify this weed groundcover by its fleshy, dark green leaves and small yellow flowers at the ends of the stems.

24. How to control it:  Purslane can be controlled well by hand pulling if you do it when the plant is young and before it goes to seed. If it's seeded itself, you can also use post-emergent broadleaf herbicide on young plants. Mulching such as thick 6mm black polythene or paddy straws Continue……..

25. Pigweed  (Amaranthus  spp ) Type:  Broadleaf annual Size:  6 feet tall, 2 feet wide Habitat :  Sunny landscape or garden areas Appearance:  Pigweeds are tall plants with a taproot. Identify weeds by their hairy-looking clusters of green flowers (though some varieties are grown as annuals).

26. How to control it:  Pull out this weed before it flowers. Also, its seeds require light for germination, so to prevent pigweed seeds from germinating, cover garden with a 3- to 6-inch layer of winter mulch. use pre emergence and post emergence herbicide Cultural and mechanical control methods. Continue……..

27. Type:  Grassy perennial Size:-  Up to 3 feet tall and several feet wide Habitat :-  Landscape and garden areas in sun or shade Appearance:-  This garden weed has wheat like flower spikes, which appear above slender clumps of grassy foliage. Quackgrass ( Elytrigia   repens )

28. How to control it:  Maintain a dense, Dig out this fast-growing grass, including the roots, as soon as you see it in your garden. It's easiest to pull when the soil is moist. A non-selective herbicide like glyphosate can be used to control a small infestation in the garden. Continue……..

29. Swallen fingergrass ( Chloris barbata ) Type: - Annual Size:-  Up to 40 cm to 1m tall Habitat :-  dry cultivated fields and waste places Appearance:-  leaves are liner with smooth edges, inflorescence is composed of 4-8cm long , flowers are wedges shaped and fleshy

30. How to control it: Mulching - apply the organic matter to suppress weed germination and growth Crop rotation Shallow tillage can uproot young plant Use pre emergent herbicides and post emergent herbicides Grazing – livestock can graze on the grass reducing its biomass and seed production . Continue……..

31. Discussion Describe the type of weed control method ? Example of pre emerge herbicides

32. Assignment Identification weeds Minimum 25 different weeds Submit as book with real specimens Deadline – 23 rd August Local names Common name Scientific name Habitat morphological feature Mode of propagation Control methods