Potato

Weed Management
  • Weeds compete with the potato crop for nutrients, moisture, light and space and also serve as an alternate host of several insect pests and diseases.
  • Wider spacing, frequent irrigations in the plains and frequent rainfall in the hills, liberal use of manures and fertilizers in potato culture provide favourable conditions for the luxuriant weed growth.
  • The potato crop develops canopy in about 4 weeks after crop emergence and weeds must be controlled by this time to gain a competitive advantage for the crop.
  • The most critical period for crop-weed competition was found to be 4-6 weeks after planting in the plains and 5-7 weeks after planting in the hills.
  • A large number of techniques and herbicides have been developed and evaluated to tackle the weed problem.
  • Hot weather cultivation in summer is particularly helpful in the destruction of weeds in soil and elimination of some of perennial weeds like Cynodon dactylon and Cyperus rotundus L. Inclusion of legume crops like cow pea and green manure crops in potato-based crop sequences reduces the population and growth of weeds in potato.
  • Planting of well sprouted seed tubers in thoroughly prepared seed beds with the application of manures and fertilizers in bands near the root zone, helps in stimulating vigorous growth of potato plants which smothers the weeds and minimises the crop weed competition.
  • An animal drawn three time cultivator popularly known as triphali is a useful implement development for weeding and tilling in potato. It can cover one ha area in a day.
  • Single bottom animal drawn ridger is used for earthing up of the crop.
  • Tractor mounted spring tine cultivator cultivates three rows at a time and tractor mounted 3-4 bottom ridger is later used for earthing up of the crop.
  • Manual and mechanical weeding removes early flush of weeds during the emergence phase of the crop.
  • Moreover, labour shortage and its high cost necessitates weed management with herbicides (table).
  • It is quicker and much less labour-intensive, and large areas can be covered with a short time with a limited amount of labour.

Herbicides for weed management in potato

Name of herbicide Dose (kg a.i./ha) Time of application Type of weed flora controlled
Fluchloralin 0.70-1.00 Pre-planting* Annual grasses and broad leaf weeds
Pendimethalin 0.5 Pre-planting* Annual grasses and broad leaf weeds
Alachlor 1.00-1.50 Pre-emergence Annual weeds, grasses and nutsedge
Atrazine 0.5 Pre-emergence Annual weeds, grasses and nutsedge
Isoproturon 0.75-1.00 Pre-emergence Broad leaf weeds.
Linuron 0.50-0.75 Pre-emergence Annual grasses and broad leaf weeds
Methabenz-thiazuron 1.00 Pre-emergence Annual grasses and broad weeds
Metribuzin 0.75-1.00 Pre-emergence Annual grasses and broad weeds
Oxyfluorfen 0.10-0.20 Pre-emergence Annual grasses and broad weeds
Simazine 0.50 Pre-emergence Annual grasses and broad weeds
2, 4-D 0.5 Pre-emergence Broad leaf weeds
Paraquat 0.40-0.60 Post-emergence** Annual grasses and broad leaf weeds
Propanil 1.00 Post-emergence** Annual grasses

  • Spray on soil before planting and incorporate in soil to reduce volatilization At 5% plant emergence.
  • The integrated weed management programme has been recommended by adopting appropriate agronomic practices for the rapid growth of potato plants along with the combination of cultural and chemical methods of weed control to reduce the weed infestation in potato crop below the threshold level.
  • Herbicide also provide timely weed control which is not possible by hand weeding over large areas.
  • A weed free environment during the early stages of crop growth can be provided only by use of herbicides.
  • During rainy season, whenever weeding is not feasible, the use of herbicides can be highly advantageous.
  • The research work conducted in this respect in Eastern dry zone of Karnataka have yielded following results.
  • The tuber yield of potato is increased by pre-emergence application of pendimethalin at 0.75 kg a.i./ha, alachlor at 1.0 kg a.i./ha or matribuzin at 0.50 kg a.i./ha.
  • These herbicides were most efficient in controlling the weed growth in potato throughout the crop growth.
  • The above herbicides were equally effective with cultural practice of hand weeding twice at 20and 35 DAS + earthing up at 35 DAS in respect of tuber yield per hectare.
  • However, the benefit cost ratio was little higher in this cultural practice of weed control.
  • Hence, weed control by pre-emergence application of pendimethalin at 0.75 kg a.i./ha, alachlor at 1.0 kg a.i./ha and metribuzin at 0.50 kg a.i./ha is most effective and cheaper than the cultural method of weed control.
  • Thus, the investigation indicated that, the pre-emergence application pf pendimethalin at 0.75 kg a.i./ha, alachlor at 1.0 kg a.i./ha and metribuzin at 0.50 kg a.i./ha increases the growth and development of the crop by their higher weed control efficiency, which suppressed the weed growth.
  • Besides they are not phytotoxic to potato crop and also do not exhibit residual toxicity.
  • Further, they are economically cheaper.
  • Based on the results of the another investigationarried out in Eastern dry zone of Karnataka on the weed management practices in potato, two hoeing + two hand weeding at 30 and 45 DAP can be advocated for satisfactory weed control, higher tuber yield and net returns in potato.
  • The next best option for effective weed control in potato was with pendimethalin at 1.0 kg a.i./ha supplemented with hoeing at 30 DAP.
  • Wherever manual weeding is not possible second option was found to be satisfactory for effective weed control, higher tuber yield and net income from potato in kharif under rainfed condition.

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Karnataka

Potato

Potato Management