Introduction

• Weeds are unwanted plants growing in crops and competing with

them for nutrients, water, space, light, etc. Weeds serve as

alternate host for several pests and diseases.

• Wider spacing, frequent irrigation and liberal use of manures and

fertilizers create favourable conditions for prolific weed growth

which can cause serious damage to potato crop. Early weed

competition affects the crop yield significantly.

• Weed management is the process of limiting the weed infestation

so that nursery could be grown profitably.

Weeds found in TPS Nursery

Scientific Name Common Name Scientific Name Common Name

Amaranthus viridis Pig weed Cyperus rotundus Nut sedge

Anagallis arvensis Pimpernel Melilotus alba Sweet clover

Avena fatua Wild oat Melilotus indica Sweet clover

Chenopodium album Pig weed Phalaris minor Canary grass

Convolvulus arvensis Bind weed Poa annua Blue grass

Cyperus iria Flat sedge Setaria glauca Carpet weed

Weed management in TPS Nursery

Weed management is a difficult task and application of various

systems together is necessary for effective control of weeds.

Following are the weed management systems:

• Cultural Method

• Physical and Mechanical Method

• Chemical Methods

Creating unfavorable environment for weeds growth to discourage its

growth in TPS Nursery.

Smother Crop Varieties: Vigorous varieties like Kufri Badshah and

Kufri Jyoti are better competitors of weeds. Incorporating green

manure crops can reduce weed infestation.

Hot Weather Cultivation: Some perennial weeds such as Cynodon

doctylon, Cyperus rotundus are reduced by deep ploughing during

summer months (May–June).

Good Seed Bed Preparation: It gives the good start to the crop by

ensuring quick emergence of potato. Mulching at appropriate time

can also reduce weed incidences in the nursery.

Cultural Method:

• Proper Planting Method: Planting of well sprouted tubers at

sufficient soil moisture, proper depth, time and maintaining high

plant densities per unit area helps reducing nursery weeds.

• Application of Light Irrigation: Application of light irrigation at

short interval helps early tuber sprouting which can compete better

with weeds in the nursery.

• Placement of Manures and Fertilizers: Application of manures

and fertilizers in bands near root zone of seedlings reduces nutrient

loss. It also deprives the weeds of nutrients thus controlling their

growth.

Cultural Method:

Cultural Methods:

• Mulching: Mulching reduces the growth of weeds in nursery. It

prevents the supply of light to the weeds thus inhibiting their

growth. It also provides an effective physical barrier to weed

emergence.

• In addition it helps to conserve moisture and maintain

temperatures conducive for germination of True Potato Seeds.

• Dry straw, grasses, paper, plastic and polythene films can be used

for mulching. Mulch should be thick enough to prevent light

penetration to suppress photosynthesis in weeds.

Physical Methods

Physical methods are also called manual and mechanical methods

of weeds control. They do not involve chemicals but require manual,

mechanical or animal energy for eradicating weeds. Manual weeding

is the mechanical method of weed control used in a TPS nursery.

Manual Weeding: Pulling out weeds by hand, hand hoe, spade etc

is a common practice for weed control in TPS nursery. This method

is also useful for destruction of weeds growing between plants

where they can not be controlled by any other means. Potato

seedlings need weed protection only until four weeks after crop

emergence.

Chemical Weed Control

Controlling weeds using chemicals can be very effective and fast

method of controlling weeds.

• Use of chemicals avoids mechanical damage to nursery seedlings

which may occur in manual or mechanical weeding. Chemical

weed control is quick and less laborious.

• Contact of herbicide may be detrimental to the seedlings and

therefore using pre-sowing herbicides must be preferred.

• Intercultural operations in nursery can be minimized by this

method.

Commonly used Herbicides

Basalin (Fluchloralin): Basalin is chemically, N–(2-Chloroethyl)–2,6-

dinitro–N-Propyl–4–(Trifluoromethyl) aniline and belongs to dinitro-

aniline group. It is volatile and available as emulsifiable concentrate or

granules. It is a pre-emergence weedicide susceptible to photo-

degradation. It is absorbed by root and translocated in the plant.

Pendimethalin (Stomp): It is chemically, N-(1–Ethyl Propyl)–2, 6

dinitro–3, 4- xylidine, belonging to dinitro–aniline group and available

as emulsifiable concentrates or granules. In potato, it is used as pre-

emergence weedicide. Pendimethalin is effective for broad leaved

weeds. It has long lasting phyto-toxicity effects.

Commonly used Herbicides

Linuron (Afalon): It is chemically, N’–(3,4–dichorophenyl)–N-

methoxy–N–Methylurea. Linuron is a substituted urea compound and

selective pre–emergence herbicide for medium to heavy soils under

medium rainfall conditions. In potato, it controls both broad leaf and

grassy weeds.

Atrazine: It is 2-Chloro–4 ethylamino–6 isopropylamino–1,3,5 triazine

compound. It absorbed through roots and translocated to other plant

parts. It is best suited in areas of low rainfall areas. It effectively

controls both Monocot and Dicot weeds and has no residual effect on

succeeding crops.