Research Achievements

Crop Protection

Coconut Diseases

Root (wilt) disease

• Established the etiology of root (wilt) disease of coconut as Phytoplasma (16Sr XI group) by electron microscopy, transmission through dodder, light microscopic staining techniques and molecular tools. Molecular detection achieved by PCR using custom designed primers.

• Identified Proutista moesta and Stephanitis typica as the potential vectors and established their role in the root (wilt) disease transmission.
• Standardized a rapid and sensitive sero-diagnostic test (ELISA) for the early detection of root (wilt) disease and integrated disease management strategies were developed for   heavily diseased tracts and mildly disease affected areas. An increase in yield of 25-83% depending on severity of disease can be obtained by adopting IDM.

Leaf rot

• Elucidated the etiology and symptomatology of leaf rot disease.
•  Disease is caused by fungal pathogens mainly Colletotrichum gloeosporioides, Exerohilum rostratum and Fusarium solani.
• Control measures using pouring of fungicide well around the base of the spindle leaf after removing the infected leaves (hexaconazole- 2ml in 300 ml of water) and use of biocontrol agents in talc formulation ((Pseudomonas fluorescens and Bacillus subtilis) singly or in consortium @ 50 gm in 500ml water/ palm) were standardized.

Bud rot

• Developed and standardised prophylactic treatment protocol for the management of bud rot of coconut  by application of 1 % Bordeaux mixture @300ml per palm or placement of 2 perforated fungicide sachets of Chlorothalonil 75WP (3 gm each) in the inner most leaf axils just before the onset of monsoon season at bi-monthly till the end of December.  Also standardized the curative treatment protocol with the application of 10% Bordeaux paste or Chlorothalonil 75WP solution (3g in 300ml of water) after removal of infected spindle portion and cover with polythene sheet.
• Developed integrated bud rot management strategy involving removal of disease advanced and dead palms, field and plant hygiene, treatment with fungicide, INM, control of other pests and diseases especially rhinoceros beetle infestation etc.

Ganoderma /Thanjavur wilt

• Developed LAMP assay for the detection of Ganoderma lucidum causing Thanjavur wilt in coconut.
• Developed and standardized management strategy for Thanjavur wilt disease by soil application of T.  harzianum (CPTD 28) enriched neem cake @ 5 kg/palm at quarterly intervals up to one year, followed by mulching and irrigation around the palm .
• Standardized the protocol for root feeding of Hexaconazole5EC @ 2% (100 ml solution per palm) at quarterly intervals for the management of Thanjavur wilt disease in coconut.

Stem bleeding

• Developed smearing methodology using talc formulation of T. harzianum (CPTD 28) in paste form for the management of stem bleeding disease by smearing the bio formulation on to the bleeding patches followed by regular water misting in the smeared area for rejuvenating the Trichoderma population.
• Standardized the protocol for root feeding of Hexaconazole5EC @ 2% (100 ml solution per palm) at quarterly intervals for the disease management.
• Complete removal of the disease affected tissues using a chisel and smearing the chiselled portion with hexaconazole (0.2%) is also recommended. Coal tar should be applied after 1-2 days on the treated portion. Destroy the chiselled diseased tissues by burning.

Fruit rot and immature nut fall

• Identified Lasiodiplodia theobromae as the major causal organism of rotting and nut fall of eriophyid mite infested coconut and spraying of Carbendazim (0.1%) or a combination product of carbendazim and mancozeb was found to be effective in controlling L. theobromae infection of coconuts.
• If coconut is cultivated under the organic farming system, spraying of garlic bulb extract (10%) can be recommended for the management of the disease.

Lethal wilt disease of coconut

• Lethal wilt disease is prevalent in Thanjavur, Thiruvarur and Pudukottai districts of Tamil Nadu. Based on the electron microscopic studies and 16SrRNA sequences and virtual RFLP, etiology of lethal wilt disease of coconut was found to be associated with phytoplasma identified as ‘'Candidatus Phytoplasma asteris'’-related strain belonging to 16SrI group.
• Being an emerging disease, periodic surveillance and removal of diseased palms is recommended in disease endemic areas.

Coconut Pests

Rhinoceros beetle

• Developed strategies for the bio-suppression of rhinoceros beetle (Oryctes rhinoceros) comprising mechanical hooking of beetles, prophylactic leaf axil filling with botanical cake admixed with sand or naphthalene ball 12g palm^-1, incorporation of Metarhizium anisopliae @ 1x 10⁸/m³ and the weed plant, Clerodendron infortunatum in the breeding site, release of Oryctes rhinoceros nudivirus infected beetles @ 10-12 ha^-1, coconut-based habitat diversification for diversionary cues  and pheromone traps with oryctalure embedded in nanomatrix @ 1 ha^-1. 

Red Palm weevil

• Evolved integrated pest management for red palm weevil (Rhynchophorus ferrugineus) comprising periodical crown cleaning, avoidance of physical injury by cutting petiole at least 1.2 m from trunk, prophylactic leaf axil management of rhinoceros beetle, curative management by spot application of imidacloprid 17.8 SL @1 ml/L or spinosad 45 SC@ 4 ml/L of water and installation of pheromone traps with ferrolure plus embedded in nanomatrix @ 1 ha^-1. 

Coconut eriophid mite

•  Developed botanical cum nutritional management of coconut eriophyid mite (Aceria guerreronis) comprising removal of dried spathes, inflorescence parts, fallen nuts  etc, spraying of neem oil garlic mixture (2%) or commercial botanical pesticides containing azadirachtin 10,000 ppm @ 0.004% or root feeding with neem formulations containing azadirachtin, 50,000 ppm at 7.5 ml azadirachtin10,000 ppm at 10 ml with equal volume of water or three sprayings of palm oil (200 ml) and sulphur (5g) emulsion on the terminal five pollinated coconut bunches or  application of talc based preparation of Hirsutella thompsonii @ 20 g L^-1 palm-¹ containing 1.6 x 10⁸ cfu with a frequency of three sprayings per year along with soil-test based nutrient application with soil and water conservation measures.

Coconut black headed caterpillar

•  Developed biological suppression strategies for black headed caterpillar (Opisina arenosella) comprising removal of heavily infested two-three outer whorls, need-based nutrition management and release of stage specific parasitoids viz., the larval parasitoids Goniozus nephantidis (Bethylidae) @ 20 parasitoids/palm, Bracon brevicornis (Braconidae) @ 20 parasitoids/palm, the pre-pupal parasitoid, Elasmus nephantidis (Elasmidae) @49/100 pre-pupae, and the pupal parasitoid Brachymeria nosatoi (Chalcididae) @32/100 pupae at the appropriate time.

Rugose spiralling whitefly

•  Evolved conservation biological control approach for the bio-suppression of rugose sprialling whitefly (Aleurodicus rugioperculatus) using the aphelinid parasitoid, Encarsia guadeloupae, in situ habitat conservation of the sooty mould scavenger beetle, Leiochrinus nilgirianus, installation of yellow sticky traps on palm trunk and field borders, spraying of water in jet-mode or neem oil 0.5% in severe cases along with need based nutrient application.
• Systematic surveillance and conducted awareness campaign on exotic pests of palms and cocoa and evolved emergency preparedness module for non-native whiteflies as well as strategies evading risks of potential invasive pests viz., Brontispa longissima, Aspidiotus rigidus, Agonoxena argaula.

Root grub

•  Developed IPM strategies for the suppression of root grub (Leucopholis coneophora) comprising repeated ploughing exposing grubs during September to January, hand picking of beetles daily in the evening for two weeks commencing from the onset of south west monsoon, application of of neem cake in the coconut basin @ 5 kg/palm, drenching the root zone with chlorpyrifos 20EC @ 2.5ml/L (10 litres /palm) or imidacloprid 17.8 SL @ 0.25 ml/L (10 litres /palm) or bifenthrin 10 EC @ 3 ml /L (10 litres /palm) during May-June and September-October and soil application of aqua suspension of entomopathogenic nematode, Steinernema carpocapsae (CPCRI - SC1) @ 0.26 billion IJs/ha (Aprox 40 - 50 lakh  infective juveniles (IJs) / 5 litre water/palm  at 5-10 cm depth in the root zone and  interspaces during June - July and September - October. Repeat application of EPN as and when needed based on the grub population

Coreid bug (Paradasynus rostratus)

• Spraying of azadirachtin 10000 ppm (Nimbecidene) @ 0.004% (4 ml/L) reduces the pest incidence. Two rounds of azadirachtin spray on 1-5 months old coconut bunches during May-June and September-October are essential for satisfactory control of the pest.

Arecanut diseases
 

Yellow leaf disease

• Etiology of yellow leaf disease (YLD) of arecanut was established as Phytoplasma by electron microscopic, transmission studies with vectors and also through molecular characterization using custom designed primers.

• Confirmed plant hopper Proutista moesta as the vector of YLD and standardized sero-diagnostic test for detection of YLD.
• Standardised IDM management strategy to be followed during initial stages of disease development. Apply 220 g urea, 200g super phosphate and 230 g muriate of potash per palm / year in two split doses during pre and post monsoon period. In addition to the above, apply one kg of super phosphate in affected gardens. Apply organic manure @ 12 kg each of compost and green leaves per palm per year. Avoid water stagnation by providing drainage facility. Control other pests and diseases.

Fruit rot and bud rot of arecanut (Mahali)

• Phytophthora meadii was found to be the causative agent of fruit rot, crown rot and bud rot diseases of arecanut.

• Developed a linear model based on multiple regression analysis to predict the fruit rot incidence four days in advance.
• Covering bunches with poly bags prior to monsoon were incorporated as a component in IDM of mahali.
• Prophylactic spraying of 1% Bordeaux mixture is effective in reducing the fungal population build up in monsoon season.

Inflorescence dieback and button shedding

• Elucidated the disease cycle of arecanut inflorescence dieback

• Spraying of Mancozeb or Carbendazim +Mancozeb @2g/lit of water is recommended for the management of arecanut inflorescence dieback.

Anabe roga or foot rot disease

• Successfully established the association of Ganoderma applanatum with the Anabe Roga or Foot rot disease of arecanut.
• Developed management strategy for the disease by soil incorporation of T. harzianum (CPTD 28) enriched neem cake @ 2kg/palm at quarterly intervals up to one year and also root feeding of Hexaconazole5EC @ 2% (100 ml solution per palm) at quarterly intervals and soil drenching @ 0.2% of Hexaconazole (20L solution per palm) or with 20L of 1 % Bordeaux mixture.

Arecanut pests

Root grub

• Developed strategies for the integrated management of arecanut root grub (Leucopholis spp.) comprising periodical digging and ploughing around palms to expose grubs to predatory birds, hand picking of beetles daily in the evening for two weeks commencing from the onset of south west monsoon, provide proper drainage, application of neem cake @ 1kg/palm during May -June and September-October in the root zone, soil drenching of Entomopathogenic nematode liquid suspension, Steinernema carpocpasae (CPCRI - SC1)  @ 1.5 billion infective juveniles (IJ's)/ ha  (Aprox 40 - 50 lakh IJs / 3 litre water /palm during June –July and September - October with insecticide, Imidacloprid 17.8 SL  (0.25 ml /L @ 2 L /palm) around the root zone and spraying of imidacloprid 17.8 SL @ 0.25 ml/L of water in the inter-spaces of arecanut palm to control early instars of root grub.

Spindle bug

• Developed integrated strategy for the effective management of spindle bug (Mircarvalhoia arecae) comprising periodical removing of dried and diseased leaflets, regulation of shade in the garden and placement of thiamethoxam 25 WG of (2 g) in perforated poly-sachets in the inner most two leaf axils of areca palms during April- May or spraying with Thiamethoxam 25 WG (0.25 g per litre water) in and around the spindle and inner whorl of leaves.

Pentatomid bugs

• Developed strategies for the effective management of pentatomid bug Halyomorpha picus comprising adoption of clean cultivation practices like collection and destruction of the various stages of the pest observed on alternate hosts viz., cowpea, bhendi, bitter gourd, chillies etc, before adults shift to areca palms, spraying neem oil emulsion (5 ml/L) at initial stage of infestation twice in fortnightly intervals and spraying clothianidin (0.24 g/L) or thiamethoxam (0.4 g/L) to the developing bunches if infestation is severe.

Cocoa diseases

Phytophthora disease

• Phytophthora palmivora (A₂ mating type) was found to be the predominant species causing black pod and stem canker diseases in India.

• Cocoa accession C78 was found to be less susceptible to black pod disease caused by P. Palmivora and also standardized the integrated management strategy against the disease by using 1% Bordeaux mixture.

Cherelle rot

• Elucidated the symptomatology, etiology and seasonal cycle of cherelle rot of cocoa in India caused by Colletotrichum gleosporioides. Also developed IDM for the disease.
• Developed strategies for the effective management of tea mosquito bug (Helopeltis spp.) comprising  shade regulation through proper pruning and training, removal of alternate hosts like neem, cashew, guava from the surroundings and spraying lambda cyhalothrin 5EC 0.3 ml/L (or) Imidacloprid 17.8 SL 0.25 ml/ L at severe infestation.

Cocoa pests

Mealy bug

• Developed integrated strategy for the effective management of mealy bug (Planococcus spp.) comprising,  conservation of lady beetles Pullus spp., Lycaenid, Spalgius epius, spot application on the pest colony with 0.5% neem oil emulsion along with 5% soap solution two-times at fortnightly intervals  and need-based application of Imidacloprid @ 0.3 ml/ L of water.

Rodents

• Timely harvest of produce and placement of 10g Bromodiolone (0.005%) wax cakes on the branches of cocoa trees twice at an interval of 10-12 day were found effective in the management of rodents in cocoa system.

Utilization of Plantation crop Wastes and other technologies developed

• Developed low cost techniques for mass multiplication of bio-control agents utilizing plantation crop wastes like coconut water and cocoa sweating. Diluted cocoa sweating was found to be superior to conventional liquid media.
• Developed a simple and highly economical low cost technology for farm level mass production of biocontrol agents using diluted cocoa sweating, bean shell and pod husk.
• Developed a very promising mycological culture medium using cocoa bean shell, an industrial waste.
• Developed technologies for production of oyster mushroom utilizing arecanut wastes.
• Developed technologies for production of coir pith formulation of Trichoderma (Trichoderma coir pith cake).
• Developed pesticide slow release product using coir pith.
• Developed low cost techniques for mass production of entomopathogenic nematodes (EPN) on field collected lepidopteron caterpillars viz., Spodoptera litura, Spodoptera frugiperda, Opisina arenosella and Oryctes rhinoceros grubs to reduce the rearing cost of Galleria mellonella in laboratory.
• Developed cropping system based nematode population management strategies for cultivation of intercrops in coconut garden.  A sequential cropping of marigold cultivation (5 months) followed by turmeric cultivation in the interspaces of coconut garden significantly suppress root - knot nematode (Meloidogyne incognita)  multiplication was resulted in improvement in  turmeric growth and yield.
• Developed integrated root knot nematode (Meloidogyne incognita)  management strategies in papaya intercropped in coconut based cropping system - includes planting of marigold (Tagetus erecta) as antagonistic crop in basin around the papaya plant and application of Trichoderma  harzianum  enriched neem seed kernel powder @ 1 kg/plant at six monthly interval.
• Developed low cost root knot nematode management strategies in vegetables intercropped in coconut  cropping system includes cultivation of  marigold (T. erecta) at 2:1 ratio of  okra ; marigold and by growing of  marigold (T. erecta) as basin crop in Noni (Morinda citrifolia) intercropped  in coconut garden  keeps  nematode away and suppress nematode multiplication.
• Biological control strategies of Spodoptera sp.  in Basella alba leafy vegetable by spraying of aqua suspension of EPN, S. carpocapsae (CPCRI-SC1) @ 5 lakh IJs / 10 liters of water in coconut ecosystem was developed.
• Developed eco-friendly management strategies for  leaf eating caterpillar (Spodoptera sp.) and  diamond back moth (Plutella xylostella) in cabbage and cauliflower vegetables  in coconut system by spraying of aqua suspension of EPN, S. carpocapsae (CPCRI - SC1 ) @ 10 lakh IJs /15 litres of water.