Dr. S. S. Punia

Principal Scientist (Weed Control)

CCS Haryana Agricultural University, Hisar

Orobanche ?

• Commonly known as broom rape, margoja, rukhri, sarson kamaama and khumbi.

• Dicotyledonous annual plant that reproduce only by seeds

• Strongly competing with other parts of the host plant forwater, mineral and assimilate absorption and unloading.

• Chlorophyll lacking root holo parasite totally dependent onhost roots.

• Seeds are usually dark brown, oval shaped, measure 0.35 x0.25 x 0.1 mm and weigh 3-6 µg

• In case of severe infestations, Orobanche can cause totalcollapse and death of crop plants

The Orobanche genus includes six species that are ofagricultural importance and cause devastating yield and qualitylosses to many agricultural crops around the globe

• O. aegyptiaca L . Haryana (Mustard, Tomato and Brinjal)

• O. cernua

• O. ramosa L.

• O. crenata Forsk.

• O. cumana

• O. minor

Haryana

Orobanche infestation in mustard in Rajasthan

5

Orobanche Infestation

Chiplima

Sporadic Infestation

Districts CropsCrop area

(acres)

Orobanche

infested area

(acres)

Erode Tobacco 4800 2125

Dindigul Tobacco 2650 1020

Coimbatore Tomato 42,500 1220

Chinnusamy, 2013

Orobanche infestation Tobacco and Tomato in Tamil Nadu

Orobanche spp. infestation in different districts of Gujarat state

Valsad

NavsariDang

Surat

Bharuch

Narmada

Vadodara

Anand

KhedaPanch-

Mahal Dahod

Sabarkantha

Am

davad

Patan

Mahesana

Banaskantha

Kutchh

Surendranagar

JamnagarRajkot

Porbandar

Junagadh

Amreli

Bhavnagar

LegendNegligibleMildMediumHeavy

Gandhinagar

Crops: Tobacco, Mustard, Tomato,

Brinjal, Potato and Chilli,

BIOLOGY: Orobanche

• Orobanche seeds germinate in the soil due to release of viz.Orobanchol and alectrol exuded by host roots 7-10 days.

• Only seeds within the rhizosphere (10 mm) of anappropriate host root will germinate.

• The parasite seedling radicle known as germ tube can growonly a few millimeters and contact a host root a few daysafter germination.

• Optimum temperature is 15-23ºC.

• GDD is the best parameter for predicting theinitiation of infestation and time of application ofherbicide.

• In general, broomrape attachment occurs at 800GDD and shoot emergence at 2000 GDD

LIFE CYCLE: Orobanche

PHENOPHASIC DEVELOPMENT: Orobanche

100-200 capsules/plant; 800-1000 seeds/capsule; 1.0-1.5 lakh seeds/plant

SEEDS: microscopic, dark brown, oval shaped, rough surfaced, 0.35x 0.25 x 0.1 mm in size, 3-6 µg in weight ,1-2 lakh/plant

SYMPTOMS: Wilting of plant

Mustard Tomato

OROBANCHE: DIFFICULT TO CONTROL?

• Seed production potential is tremendous (Av.1,00,000-1,50,000 per plant) .

• Underground location- inaccessible to conventionalcontrol measures.

• Late appearance of parasite shoots above the soil.

• Lack of photosynthetic system.

• Higher seed longevity: 10-13 years.

• Tiny small seeds easily dispersed due to animals,farm machinery, organic manures etc.

• Seed viability is not lost after passing animaldigestive tract.

PREVENTIVE MEASURESPhyto-sanitary measures for avoiding the dispersal of Orobancheseeds from infested locations are as :

• Prevent movement of infested soil by vehicles, farm machineryand planting material.

• Clean farm, machinery and equipment i.e., tractors, combines,containers, etc.

• Prevent spreading seeds by farm animals. Since Orobanche seedsmay pass animal digestive systems without losing viability, grazingon or feeding hay from broomrape infested fields is prohibited, aswell as using animal manure from unknown sources.

• Use only certified seed.• Prevent Orobanche seed dispersal by wind or water soil erosion.• Collect parasitic weeds prior to flowering.• Practice deep tillage (>20 cm) during hot summer months.

CULTURAL MEASURES: Limitations

• Late sowing – Significant yield reduction

• Crop rotation – wheat, barely, gram, lentil and longer viability

• Higher fertilizer requirement- 120 kg N/ha in three equal splits

• Flooding – undulating topography and light soil texture

• Deep Tillage- No inversion in light soils

• Soil solarization – Possible on small scale

• Trap crops/suicidal parasite germination – Not feasible, higherrate of seed production

• Catch crops – Not feasible and needs several repeated seasons,only small percentage of seeds is stimulated

• Host plant resistance/tolerance

• Hand weeding – regeneration and only to reduce seed bankfor next season

FUNGICIDES: No Control

• Psuedomonas inflorescence at 3.75 kg/ha at sowing

• Trichoderma viridae at 3.75 kg/ha at sowing

BIOLOGICAL CONTROL : Phytomyza orobanchia

Limitations: Mass rearing, release, formulation and delivery system

CHEMICAL CONTROL: Use of Kerosene and Soybean oil

Spray of soybean and kerosene oil was not atall effective at any concentration. Moreover, itis not feasible to spray soybean oil due to itshigh viscosity.

Use of kerosene oil on Orobanche panicles

Use of two drops of soybean oil/panicle

PROTECTED SPRAY: Glyphosate and Paraquat in Mustard

• Protected spray of glyphosate at 0.5, 0.75, 1.0 and2.0 % (product basis) or paraquat at 0.3, 0.5 and0.75% applied after emergence of Orobancheaegyptiaca during first week of February caused onlylocalized burning of Orobanche panicles.

• Of no use except to prevent seed formation.

• More over not feasible to spray at this stage.

CHEMICAL WEED CONTROL

• Very few herbicides are selective to host crops

• Limited in their movement

Three type of herbicides can be used:

• Soil fumigants

• Residual soil applied herbicides

• Post emergence applied herbicides

SOIL FUMIGANTS

• Methyl bromide: Moist soil conditions are needed. Erraticresponses due to evaporation and difficulty in fumigatingmedium to clay heavy soils.

• Methylisothiocynate compounds: Metham sodium appliedby injection or via chemigation or irrigation systems in soil.Effective in deep layers but poor on surface soils due toevaporation losses.

*Can be dangerous to environment

RESEARCH DONE SO FAR………

• Different sources of nutrient supply in mustard i.e.SSP, Urea, CAN, poultry manure, vermi compost,castor cake and FYM – NOT EFFECTIVE

• No genotype of mustard and tomato found tolerantagainst Orobanche spp.

• Neem cake alone or in combination with metalxylproved ineffective in tomato, mustard and brinjal.

• Plant hole application of neem cake 200 kg/ha at 30DAT in tobacco provided effective control ofOrobanche under Tamil Nadu conditions.

No efficacy against Orobanche and even poor control of annual weeds due to lesssurface moisture

PRE-EMERGENCE SPRAY: Pendimethalin

Chemical weed control in mustard

SEED TREATMENT: Soil applied herbicides

• Delayed Orobanche emergence up to 90-110 DAS.

• No availability of chlorsulfuron and triasulfuron in the market.

• 10-15% reduction in mustard germination.

• No feasibility of adoption by farmers due to low dose.

ChlorsulfuronTriasulfuron

Sulfosulfuronat 0.1—1 ppm

Glyphosate: Application & Translocation

Glyphosate

• Glyphosate applied at 25 g/ha at30 DAS and 50 g /ha at 55-60 DAS

• Addition of (NH)4SO4 at 1.0%enhances the efficacy ofglyphosate

• Avoid moisture stress at time ofspray

• Dose and time of applicationshould be strictly followed.

• Repetitive/higher dose may leadto adverse effect on mustardcrop.

Use of Glyphosate

Glyphosate untreatedGlyphosate treated

LEAF CHLOROSIS due to 50 g/ha application of glyphosate

Recoverable within 7-10 days

Two sprays of ethoxysulfuron/sulfosulfuron at 25 & 50 g/haat 30 and 60 DAT, respectively provides 85-90 % control ofOrobanche.

No any adverse effect on crop

Yield advantage of 46-58 % as compared to untreated check.

October planted tomato needs two sprays of eithersulfosulfuron or ethoxysulfuron (25 & 50 g/ha) at 30 and 60days after transplanting where

Tomato transplanted in second fortnight of November needtwo sprays of sulfosulfuron and ethoxysulfuron at 50 g/ha at60 and 90 DAT.

Chemical weed control in tomato

Pre-emergence use of 25 g/haethoxysulfuron followed by postemergence application at same rateat 45 DAT although effective incontrolling Orobanche but causesstunted growth unrecoverable up to90 DAT resulting in poor yield .

No herbicide residues were observedin tomato fruits and soil at harvest.

No residual carry over effect of theseherbicides on succeeding sorghumplanted two months after harvest oftomato.

Tomato hybrids: Himsona, US 2853,Sampuran, Himshikhar, Namdhari,Rakshak, Satyam are not sensitive toany herbicides.

Chemical weed control in tomato

Glyphosate toxicity in tomato

Ethoxysulfuron(PRE) toxicity

Diagnosis of Orobanche infested tomato plants

32

• Neem cake + pendimethalin/metribuzin fb soil drenching of metalaxyl MZ 0.2 % at 20 DAT – NOT EFFECTIVE

• Metribuzin at 3 DAP - highly toxic to brinjal resulting in complete mortality.

• Excellent control of Orobanche with POST or PRE plus POST treatments of sulfosulfuron and ethoxysulfuron but highly phytotoxic to brinjal.

• Broom rape spikes which emerged in ethoxysulfuron andsulfosulfuron treatments were very weak and smallsized.

• Ethoxysulfuron 25 g/ha, PRE was more phytotoxic than POST and brinjal exhibited 50-60% growth reduction under pre treatments resulting in cracked and wrinkled fruits.

• Developmental delay in brinjal with ethoxysulfuron and sulfosulfuron applied PRE or 30 DAS.

• Maximum fruit yield (32.0 t/ha) was recorded from use of sulfosulfuron 25 g/ha at 60 and 90 DAS, respectively which was which was 22.1 % higher than untreated check and significantly higher than all herbicide treatments.

Orobanche management in brinjal

WP 3.2.1 (a) Orobanche management in brinjal

0

10

20

30

40

50

60

70

80

90

NC fb pendifb metalxyl

Ethoxy 25g/ha (PRE)

and 50 g/haat 45 DAT

Ethoxy 25g/ha at 60 &

90 DAT

Sulfo 50g/ha at 60

and 90 DAT

Sulfo 25g/ha at 60

and 90 DAT

Weedycheck

0

82 85 85 85

0

24.220.6

25.728.8

32

24.9

0

50

30

38

10

0

Orobanche panicles/m2 visual control(%)Fruit yield (t/ha) crop phytotoxcity( %)

Ethoxysulfuron 25 g/ha, PRE was more phytotoxic than POST

and brinjal exhibited 50-60% growth reduction under pre

treatments resulting in cracked and wrinkled fruits.

Tamil Nadu

Plant hole application of neem cake at 200 kg/ha on 30 DAT.

DCA of imazethapyr 30 g/ha at 55 DAT.

Neem cake 200 kg/ha at sowing fb soil drenching of metalaxyl0.2 % at 20 DAP.

Karnataka

Growing of trap crops (sun hemp/green gram) in the early spring and incorporate in-situ 45 DAS

Apply imazaquin at 30 DAT at 0.01 kg/ha or one hand weeding within 45 DAT

Apply glyphosate 0.5 kg/ha at 60 DAT and remove theremaining spikes with hand.

Chemical weed control in tobacco

Sequential application of glyphosate (20 + 40 and 20 + 40 +60 DAPE) at 60-80 g/ha.

Injuries in the form of leaf yellowing, plant stunting andcompact plants occurred at 10 days after first spray butdisappeared by 75 DAPE with significant on plant height at60 DAPE.

Higher dose of 100 g/ha although effective but causedeformed and small tubers.

Timing of application varies among potato varieties andgrowing seasons.

(Haidar and Shdeed 2015), Lebanon

Chemical weed control in potato

Three repeated application of rimsulfuron at 12.5 or 25 g/hasprayed at two weeks after crop emergence and reapplied at twoweeks intervals controlled Orobanche and found safe for potatoesas well as tuber quality.

Rimsulfuron is registered for use in commercial crop of potato.

Split application of three doses of 5 g/ha each imazapic applied at10, 20 and 30 DAPE through foliar or chemigated through sprinklerirrigation caused suppression in Orobanche aegyptica.

Although crop vigor, potato yield were good but tuber quality wasseverally damaged in light textured soils.

Triasulfuron is very toxic to potato at 7.5 to 15 g/ha resulting incurly leaves and inhibited crop growth

(Goldwasser et. al. 2003), Israel

Chemical weed control in potato

Use of post emergence spray of glyphosate by farmers

Preparation of glyphosate dose for OFT

FIELD DAY: Orobanche Management

CONCLUSIONS

• Several methods for managing broomrapes include hand weeding, deep ploughing,crop rotation, alteration in seeding windows and fertilizer N scheduling, theapplication of organic manures, chemical seed treatment,; however, they areinconsistent and have limited effectiveness.

• Each of these methods has its merits and provides its own or in combination withothers a solution to certain situations, but the general problem remains somewhatunresolved.

• No single technique provides complete control of Orobanche, and resorting to someof them is unavoidable.

• Physical methods are very useful to prevent the Orobanche but are tedious, time-consuming and costly and prevent only seed setting not yield losses.

• Chemical, agronomic control methods and host resistance appear to be the mostappropriate measures when available and affordable.

• Integration of cultural, preventive and biological and chemical methods is requiredeven though it is very costly to deplete weed seed bank and to avoid furtherdispersal. However, these integrated programmes are practiced only on a small scalein a few countries because of cost and technical problems. Therefore, it is reasonableto hypothesize that GMO approaches will be adopted for parasitic weed control in thenear future.

Future Thrusts……….

• Surveillance system for regular monitoring should be sound.

• Training of research specialists, extension workers andfarmers on biology and ecology of Orobanche and controlmeasures.

• Continued research programme towards cost effective,technically sound and environmentally viable interventions.

• Genetically engineered herbicide resistant crops.

• Development and dissemination of improved technologiesthrough use of appropriate aids such as technical leaflets,manuals, broachers in regional language.

• Holistic, systematic and farmers’ participatory approach.

• Practical demonstrations at farmers’ fields.

SYMBOL OF TRUST