Salient Research Findings of DWSR

i.   National database on weeds

• Information on major and minor weeds of 435 districts of the country has been incorporated in the database. Weed maps of 19 states have also been developed.

• A weed seed repository of about 150 weed seeds with a weed seed identification kit as Weed Seed Atlas has also been developed.

ii.   Weed management in crops and cropping systems

• Cowpea or dhaincha as an intercrop + Pendimethalin (1.0 kg/ha) PE fb. manual weeding (20 DAS) was found effective for reducing weed competition In upland direct-seeded rice.

• Summer ploughing fb glyphosate application (2.0 kg/ha) at 4-6 leaf stage during April-May was found very effective in controlling Saccharum spontaneum (Kans).

iii. Herbicidal techniques

• Herbicide recommendations for various crops and cropping systems have been made based on the multi-disciplinary and multi-location trials conducted in different agro- climatic zones.

• Continuous use of butachlor in rice and isoproturon in wheat has reduced the problem of Echinochloa colona in rice and Phalaris minor, Cichorium intybus and Chenopodium album in wheat.

• In onion, oxyfluorfen (200 g/ha) or pendimethalin (1.0 kg/ha) fb one manual weeding was found in reducing weed infestation and resulted in higher bulb yield (63 q/ha).

• In soybean, mixture of chlorimuron+fenoxaprop at 6+100 g/ha for broad-spectrum and flumioxazin at 60 g/ha as PPI or pre-emergence for broadleaved weeds.      

iv. Cultural techniques

• Soil solarization (covering the soil with transparent polythene films) alone as well as with FYM at 5 t/ha for a period of 6 weeks has shown excellent control of most of the annual weeds in sesame-tomato systems.

• In rice-wheat system, zero-tillage in wheat has reduced the population of Phalaris minor whereas wild oat population increased.

• Continuous adoption of rice - lentil system has reduced the problem of Phalaris minor in lentil. The problem of Cichorium intybus, Medicago hispida and Chenopodium album, has however, increased in sorghum-chickpea system.

• Soybean-chickpea system has been found to increase the problem of Euphorbia geniculata.

v. Competitive crop cultivars

• Upland rice cultivars Vandana, Kalinga-III and RR-151-3 have shown better weed competitive ability and higher yield potential under sub-optimal weed management condition.

• Quick growing and spreading type pea cultivar JP885 has been quite effective in weed suppression.

• Cultivars of major crops like wheat (18 no), rice (10 no), pea; chickpea (13 no) have been evaluated for their weed competitiveness.

vi. Management of problem weeds

• Quizalofop @ 125-150 g/ha has been found effective in managing Saccharum spontaneum in mustard, chick pea and pea.

• Oxadiazon (0.5 kg/ha) and pendimethalin (1.0 kg/ha) as pre-emergence have reduced the infestation of Asphodelus tenuifolius in chickpea.

• Pre-emergence application of pendimethalin (1.0 kg/ha) has effectively controlled parasitic weed Cuscuta spp. in niger and urdbean. Post-emergence (2 weeks after sowing) application of pendimethalin 0.5-0.75 kg/ha has been found safe and effective in lucerne.

• Cassia serecea, Cassia tora, and marigold found promising in suppressing the growth of Parthenium.

• Metsulfuron-methyl (6-20 g/ha) was found to give effective control of Alligator weed (Alternanthera philoxiroides) in aquatic bodies and low land areas.

 vii. Biological control

• Mexican beetle, Zygogramma bicolorata has been proved to be an effective bio-agent against the problem weed Parthenium hysterophorus. The beetle has been successful in suppressing the weed in several localities in and around Jabalpur.

• Neochetina spp., an exotic insect has successfully suppressed water hyacinth in three ponds of Jabalpur.

viii. Mechanical tools

• Weeding tools collected from different parts of the country were evaluated and improved for controlling weeds in crops.

• A wick applicator was developed for application of non-selective herbicides in standing crops like mustard and soybean.

ix. Impact of herbicides on environment

• Monitoring of herbicide residues in soil, water and food chain, in different crops and cropping systems throughout the country revealed that none of the herbicides used at recommended doses and time of application, persisted at levels above the safety limit in soil and edible plant parts.

• Residual effect of different herbicides viz. fluchloralin, pendimethalin, metolachlor and oxyfluorfen applied in different crops like blackgram, okra and cotton did not disturb the biological balance of soil microflora (bacteria, fungi and actinomycetes).

• 2,4-D, glyphosate, paraquat have shown detrimental effect on earthworms.

x. Global climate change

• Elevated CO₂ (550 ppm) has drastically enhanced the plant growth, shoot and root biomass, production of flowers in Parthenium hysterophorus and Amaranthus viridis.

• Elevated CO₂ has hastened the maturity in wild oat.

• The mortality of weeds due to herbicide application has been delayed under elevated CO₂.

• Elevated CO2 drastically enhanced the growth, shoot and root biomass,  production of flowers of Parthenium

xi. National weeds herbarium & weed cafetaria

•  A weed cafeteria containing germplasm of 100 weeds has been developed.

xii. Weed utilization

•  Biomass of several weed species like Parthenium, Lantana, Mikania, Chromolaena, Cassia, Ipomoea carnea, Salvinia, water hyacinth etc. can be utilized for mulching and in preparation of compost/ vermicompost.

• Compost prepared from Parthenium and water hyacinth has been found to be equivalent to FYM in nutrient content.

• Parthenium biomass has also been used for making paper and particle boards.

xiv. National Invasive Weed Surveillance (NIWS)

• Five quarantine weeds intercepted from the wheat imported during 2006-07 for Public Distribution System (PDS) from various countries have been detected by different National Invasive Weed Surveillance (NIWS) Centres