Noxious weeds

Noxious weeds

What is Noxious Weeds?

Noxious weeds are weeds that is harmful to Horticulture-Agriculture crops, live stocks, environment etc, which leads to lethal effects on the Agriculture economy of the country at all. Such weeds are very difficult to control, however certain chemicals are very effective to control these weeds.

List of the Major Noxious Weeds as under:

  1. Cynodon dactylon-Dharo
  2. Cyperus rotundus-Nut Grass
  3. Convolvulus arvensis-Field Bind Weeds
  4. Parthenium hysterophorus –Gajar Grass
  5. Sorghum halepense –Johnson Grass
  6. Typha angustifolia-Narrow Leaf Cattail
  7. Phalaris minor- Gullidanda
  8. Eichhornia crassipes-Water hyacinth
  9. Cuscuta reflexa- Amarvel
  10. Striga asiatica-Agiyo
  11. Lantana camara- Lantana

In agriculture, we have four main enemies: DISEASE, PESTS, RODENTS AND WEEDS. Out of this, 26.3 percent by disease, 9.6 percent by pests, 13.8 percent by mice and THE HIGHEST 33.8 PERCENT BY WEEDS have been recorded in crop production. Weeds can cause 10 to 100 percent yield loss in different crops. A Noxious weeds growing alongside other crops, reducing crop yield and quality, increasing the cost of cultivation, persisting even in adverse climate is the biggest and hidden enemy of farmers.

Thus, most perennial weeds are not particularly difficult to control. The weeds which cannot be controlled by any means are called noxious weeds. Such weeds with a life span of more than two years are also called perennial weeds.

Noxious weeds

Noxious weeds

(1)Cynodon dactylon

  • Cynodon dactylon is a perennial, shallow-rooted, monocotyledonous weed.
  • Occurs in all places, in all seasons and in all crops.
  • Vigorous growth occurs especially in hot and humid conditions.
  • Occurs in different types of soil. Black, loamy fertile and moist soils are more suitable.
  • Its spread is mainly through rhizomes and cuttings.
  • It produces seeds, although seeds are not important for reproduction.
  • In irrigated crops as well as in orchards, the problem of soil has become acute.

Control:

  • In semi-arid areas deep plowing in summer to expose the root nodules to the heat of the sun is very effective.
  • The exposed nodes take 7 to 14 days to dry, followed by another tillage.
  • Herbicides such as Dalapon, TCA, Diuron, Glyphosate, Amitrol-T and Uracil prior to tillage improve Cynodon dactylon
  • As these drugs are transported to the root nodules, long-term and complete control is achieved.
  • 120 ml of glyphosate drug at 3-4 leaf stage and 100 to 150 grams of ammonium sulphate or urea dissolved in 10 liters of water should be sprinkled in such a way that the weeds are properly soaked.
  • Paraquat and diquat are very suitable in intensive farming system. These medicines are non-residual and dry the roots in 15-20 days.
  • Spraying these drugs twice a week before sowing in summer gives good results. Efforts like this for two to three years can weaken the weed infestation.
  • But summer tillage is not very useful for Cynodon dactylon control in humid and erosion prone conditions. In such areas weed killers have to be relied upon.
  • The cropping system should include widely spaced crops and frequent intercropping.

Noxious weeds

Noxious weeds

(2)Cyperus rotundus

  • Cyperus rotundus is a perennial, deep-rooted monocot weed. Occurs everywhere, in all seasons and in all crops, although there is less growth in winter.
  • Occurs in all types of soil, even rocky soil. It prefers black, sticky, fertile and moist soil.
  • Its production and dissemination is mainly by tumor 90-95% and seed 5-10%.
  • In soil 56 new plants and 260 new nodes can be produced in one square foot of soil.
  • Cypress rotundus species is found in our area among the species.
  • Since the leaves of Cyperus rotundus are smooth and thick, the medicine cannot stay on the leaf, it is not properly absorbed by the leaf. Also, if there is a series of nodules in the soil, the absorbed drug reaches only one or two nodules. So a new plant sprouts from the remaining nodes. Thus it is not possible to completely control, however, Cyperus rotundus can be controlled with a combination of treatments.

  Control:

  • Deep plowing in summer to heat the soil in the intense heat of the sun.
  • Collect the roots and destroy them.
  • If possible, solarize the soil by placing a plastic cover on the soil for 15 days in the month of May-June.
  • Killing the plant by frequent tilling, so that the food stored in the underground nodules is emptied and the nodules slowly rise up.
  • Planting shade crops like Jowar, Tuvar, Castor, should be shade tolerant.
  • Spreading wheat husk on clay soil.
  • Glyphosate 120 ml at 3-4 leaf stage of Cyperus rotundus Accordingly, dissolve 100 to 150 grams of ammonium sulphate or urea in 10 liters of water and sprinkle the solution in such a way that the weeds are properly soaked.
  • Glyphosate is a non-descript herbicide and cannot be sprayed on standing crops. However, in widely spaced crops, directional spraying can be done in such a way that the drug does not fall on the crop. Soil should be moist at the time of spraying.
  • Don’t perform any agricultural operation for 20 days after spraying.
  • For Chemical weed control, spray halosulfuron 67.5 gm per hectare (1.8 gm per 10 liters of water) solution, when crops are not in the field, in such a way that the weeds are thoroughly soaked. Do second spraying in 1 to 2 months on re-emerged Cyprus rotundus This herbicide cannot be sprayed in standing crops except sugarcane. In this way, constant care can gradually control the Cyperus rotundus.

Noxious weeds

Noxious weeds

(3)Convolvulus arvensis:

  • For the past few years, the problem of Convolvulus arvensis in our area has become serious. Convolvulus arvensis is a perennial, deep-rooted, creeping dicotyledonous weed.
  • Its roots can go up to 3 meters deep in the soil, is a perennial plant. However, it remains dormant in drought conditions.
  • Its reproduction is mainly through roots and seeds. The seeds have a very long dormant period. It can spread up to 3 meters in circumference by root cuttings in one season.
  • Convolvulus arvensis occurs in cultivated, orchard and non-cultivated areas in semi-arid areas.
  • It occurs more in wheat, cotton, pigeon pea, castor, potato and sugarcane crops.
  • Being a perennial weed, it binds the crop plants, making it difficult to harvest the crop.

Control:

  • Convolvulus arvensis plants can be killed by herbicides or by hand weeding or intercropping. But if the root is deep, a new plant is produced again from its cuttings.
  • At present cotton is grown on a large scale in our area. Convolvulus arvensis is a broadleaf weed like cotton, no herbicide can be sprayed, especially 2,4-D, which is ineffective against Convolvulus arvensis. However, deep plowing in summer heats the soil in the intense heat of the sun.
  • Collect and destroy the roots. Cultivation every 15-20 days in fallow land to destroy tuber plants.
  • Rotation of fodder crops.
  • Spray 2, 4-D (sodium salt), 25 grams per 10 liters of water after 30-35 days after planting millet, corn, jowar, wheat.
  • Do not spray 2,4-D if cotton is planted in the vicinity or if cotton is to be harvested later.
  • Good control by spraying glyphosate, dicamba  cametasluron with 2,4-D.

Noxious weeds

Noxious weeds

(4)Parthenium hysterophorus:

  • Carrot grass is a dicotyledonous weed insensitive to rainfall, light and temperature.
  • It is mainly produced by seeds. A single plant produces 5,000 to 10,000 seeds.
  • Apart from this, when the stem is cut from the mother plant, a new plant sprouts from its bud. Grows in monsoon and continues to grow even in winter.
  • Growth becomes stunted in summer. Infestation of this weed is especially common in roadside residential or other fallow lands.
  • The infestation is not frequent in the crop area, but is now found in many crops.
  • Due to the poisonous element Parthenin’ in it, allergic diseases of skin and mental stress are caused in humans.
  • Its pollen is very harmful and many diseases also occur in animals.

Control:

  • A hand-pulling is recommended when carrot weed is found in a new area. For this, volunteers wear gloves and ensure that the plant is uprooted up to the crown area.
  • 2,4-D (sodium salt) 50 g per 10 liters of water should be sprayed on the plants during the active growth period of the weed in the area where carrot grass is established.
  • Effective control can be achieved by spraying diquat or glyphosate 1.0% (100 ml per 10 liters of water).
  • Apart from this, metribuzin 0.5% (50 g per liter of water) or metsulfuron 1 g per 10 liters of water or chlorimuron 1 g per 10 liters of water can be sprayed.
  • Spraying of recommended weedicides on crop like atrazine, cimazine, alachlor2, butachlor, diuron, nitrofen etc. before crop and weed emergence can effectively control carrot grass for 2 to 5 months. Biological control of carrot grass can be achieved by releasing the Mexican beetle i.e. Zygogramma bicolorata in fallow areas.
  • Planting marigold etc to replace carrot grass in fallow areas.

Noxious weeds

Noxious weeds

(5)Sorghum halepense:

  • It is a perennial grass up to 2 meters tall. It is produced by vegetative roots and seeds.
  • Its roots can go as deep as 3 meters into the soil, although usually 30-35 cm in depth.
  • Sorghum halepense plants produce abundant seeds in winter and spread by wind. Then the old roots go dormant. New shoots appear in summer and take root in 3-4 weeks.
  • Sorghum halepense are found especially in crops like maize, millet, sugarcane, cotton in heavy black and moist soil.

Control:

  • Deep plowing in summer.
  • Apply two sprays of Dalapone 5-7 kg on a new plant at 7-10 days interval per hectare.
  • Sow cotton, maize, soybeans after plowing with disc plough.
  • 99% control by spraying with TCA 30 kg per hectare.
  • Spray any one of Dalapon, Diuron, Bromacil or sodium chlorate, glyphosate, paraquat before flowering in fallow areas.

Noxious weeds

Noxious weeds

(6)Typha angustifolia:

  • Narrow Leaf Cattail is a grass class weed. Its plants are 1.5-2 meters tall. Leaves and stems are erect. Leaves long, dark, 5-12 mm broad and without a central vein.
  • Its tail is like a cat’s tail. It is produced by vegetative as well as microscopic seeds.
  • A pod contains 10,000 to 20,000 seeds which have a long dormant period. It is mainly found in muddy and water-logged areas and along the banks of canals.

Control:

  • In summer dry the canal, farm ponds, reservoirs etc.
  • Spray Dalapon 2% solution for chemical control.
  • Spray Dalapon 15 kg + Amitrol 3 kg Or Amitrol 3 kg + TCA 10 kg per hectare.
  • Spray cymazin, diuron, gyaphosate or paraquat on canal, farm ponds,vacant area before  weeds emergence.

Noxious weeds

Noxious weeds

(7)Gullidanda (Phalaris minor):

  • It is a non-native invasive weed in wheat crop. In Punjab, Haryana and Uttar Pradesh, farmers have been disturbed by terror in wheat.
  • It closely resembles wheat and barley in appearance, seeding at the same height and time.
  • Each plant produces 300 to 460 shiny, black, very small, flattened seeds.

Control:

  • Use weed free seed. For this, sift wheat and barley seeds and separate the seeds of Gullidanda.
  • Crop rotation. Cultivation of chickpea, mustard, maize instead of wheat crops so that it can be identified and destroyed before flowering.
  • Do not use it in animal feed.
  • For effective control spray Isoproteuron 5 kg/ha (20 ml in 10 liters of water) 20-25 days after sowing the crop.
  • Chills can also be controlled with this weedicide.
  • In non-irrigated wheat 25 grams of Sulfosulfuran dissolved in 500 liters of water and spray 30-35 days after sowing can give effective control of Gullidanda.

Noxious weeds

Noxious weeds

(8)Eichhornia crassipes:

  • Eichhornia crassipes is aquatic plants that grow and float in water.
  • 10-20 cm broad leaves float in water
  • Stem is long and soft
  • The inflorescence has a peduncle of 30 cm. Each tuber has 8-15 yellow flowers. Each flower produces 3,000 to 4,000 seeds.
  • Its seeds remain alive under water for 15 years.
  • It’s reproduction by vegetative mrthod.
  • One plant can infest an acre in one year.

Control:

  • Pull such plants from water or canal, dry and burn it
  • Placing a net at the entrance of the canal can prevent the arrival of Eichhornia crassipes.
  • Where water is not to be used for drinking or drinking purposes 2,4-D 1.0 kg active ingredient per hectare can control Eichhornia crassipes
  • Eichhornia crassipes can also be controlled by applying 2-4-D sodium salt 2.0 kg. + Glyphosate, 0.5 kg or 2,4-D (sodium salt) 2.0 kg. + Paraquat 0.5 kg per hectare (water should not be used for irrigation and drinking).
  • For biological control Neochaetina irconi and Neochaetina buchi are used. 80-90% of the success has been achieved using both these bio control agent.

Noxious weeds

Noxious weeds

(9)Amarvel (Cuscuta reflexa):

  • Cuscuta reflexa is a perfect parasite weed. There are about 170 species in the world.
  • The seeds can survive for 8-10 years. No stimulant is required for seed germination.
  • The growing roots of amarvel are directly attached to the roots of the crop.
  • A plant of Amarvel can extend up to 2 km.
  • Alfalfa is the main host crop, besides bersim, ramtal, linseed, mung bean, urad, chana, it is also found on many trees and shrubs.
  • It spreads through seeds and cuttings.

Control:

  • Sow weed free seeds.
  • If possible, give one irrigate, then plough the land to destroy the weeds.
  • Crop rotation using monocots (wheat, millet, barley) and planting sunflower, guar or jute crops.
  • Remove the damaged plants affected by Cuscuta reflexa and destroy that part by burning.
  • Make a solution of the Paraquat 40 ml in 10 liters of water and spray it after harvesting alfalfa
  • Then water it for 2 days so that the parasite is killed by the contact weedicide.
  • For control of Cuscuta reflexa in alfalfa, spray Pendimethalin 0.5 kg/ha (10 liters 33 ml in water) 10 days after sowing alfalfa.
  • In oilseed crops spray Pandimethalin 0.9 kg/ ha (60 ml drug in 10 liters of water)  after sowing but before crop and weed emergence.

Noxious weeds

Noxious weeds

(10)Striga asiatica:

  • Striga asiatica are rainfed and partly parasitic weeds.
  • It is produced by seeds. A special stimulant is required for seed germination.
  • After 20 days complete parasite life in the soil emerges from the soil as a green plant.
  • After 30 days after emerging from the soil, Striga asiatica plants produce millions of seeds. Its seeds are very fine like clay particles.
  • Flower color is white to pink. There are 23 species of Striga asiatica in the world, only three of them are problematic.
  • Only Striga asiatica/ Laetitia is seen in Asia .
  • It is found in maize, sugarcane, tobacco, groundnut, sweet potato etc. besides jowar, millet.
  • Striga asiatica reduces sorghum production by 15-75%.

Control:

  • Before flowering Striga asiatica should be uprooted and destroyed.
  • 30-45 days after planting in sorghum crop spray 2,4- D (Ester) 1.0 kg/ha (50 ml of drug in 10 liters of water) for effective control.
  • Spraying 20% urea or 5% ammonium sulphate at flowering gives complete control of Striga asiatica.
  • Effective control can be achieved by giving Granular atrazine 0.5-1.0 kg/ha before weed emergence in sorghum, maize, sugarcane.
  • Planting of staple crops like cotton, sunflower, groundnut, chickpea, castor or pigeon pea reduces the infestation of Striga asiatica.

Noxious weeds

Noxious weeds

(11)Lantana (Lantana camara):

  • Lantana camera is a perennial, invasive, non-native imported weed.
  • Allegedly having multi colored flowers imported from Sri Lanka as an ornamental fence. But now its spread is in grazing area, riverine area, fallow land, Embankments, roads, forest areas, parks, tourist spots and also in crop areas.
  • Its seeds are spread mainly by birds.
  • Lantana camera leaves contain a toxic chemical called LANTRADENE, which causes liver ulcers in animals and alters blood plasma.

Control:

  • Spray glyphosate 0.75-1% solution (75-100 ml in 10 liters of water) on the trunk after cutting or burning it.
  • A mixed spray of glyphosate and metsulfuron increases efficacy.

Benefits of Lantana camera  

  • Cut Lantana camera plants can be used as green waste, for making liquid manure and in biogas plants.

Summary:

Noxious weeds are harmful to agriculture, crops, live stocks, and the environment, causing lethal effects on the country’s agriculture economy. Major noxious weeds include Cynodon dactylon (Dharo), Cyperus rotundus (Nut Grass), and Convolvulus arvensis (Field Bind Weeds). These weeds can cause yield loss in different crops and can be controlled using herbicides like Dalapon, TCA, Diuron, Glyphosate, Amitrol-T, and Uracil.

Cynodon dactylon is a perennial, shallow-rooted, monocotyledonous weed that occurs in all places, seasons, and crops. Its growth is mainly in hot and humid conditions and prefers black, loamy, fertile, and moist soil. Cyperus rotundus is a perennial, deep-rooted monocot weed that occurs everywhere, in all seasons, and in all crops. Control measures include hand-pulling, spraying 2,4-D, diquat, glyphosate, metribuzin, metsulfuron, and chlorimuron.

Convolvulus arvensis is a perennial, deep-rooted, creeping dicotyledonous weed that occurs in cultivated, orchard, and non-cultivated areas in semi-arid areas. Control measures include deep plowing, collecting and destroying roots, cultivating every 15-20 days in fallow land, and rotating fodder crops.

Carrot grass is a dicotyledonous weed that is insensitive to rainfall, light, and temperature, producing 5,000 to 10,000 seeds per plant. Control measures include hand-pulling, spraying 2,4-D, diquat, glyphosate, metribuzin, metsulfuron, and chlorimuron.

Sorghum halepense is a perennial grass that can grow up to 2 meters tall and produces abundant seeds in winter. Control measures include deep plowing, applying two sprays of Dalapone, sowing cotton, maize, and soybeans, and spraying Dalapon, Diuron, Bromacil, sodium chlorate, glyphosate, and paraquat before flowering.

Eichhornia crassipes is an aquatic weed with 10-20 cm broad leaves that float in water. Control methods include pulling plants from water or canals, drying and burning them, and placing a net at the canal entrance. Control methods include sowing weed-free seeds, irrigating and ploughing the land, crop rotation using monocots, and planting sunflower, guar, or jute crops.

Striga asiatica is a rainfed and partly parasitic weed that emerges from the soil after 20 days and produces millions of seeds. Control methods include uprooting and destroying Striga asiatica before flowering, spraying 2,4-D (Ester) 1.0 kg/ha, and giving granular atrazine 0.5-1.0 kg/ha before weed emergence. Lantana camera is a perennial, invasive, non-native imported weed with multi-colored flowers imported from Sri Lanka as an ornamental fence.

Noxious weeds

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