Research Achievements of Crop Protection

Management of soybean diseases

Integrated management schedules of root, seed and foliar diseases ( charcoal rot, collar rot, rust, Myrothecium leaf spot, bacterial pustule, yellow mosaic etc.) have been worked out. Strain variation in Sclerotium rolfsii and Xanthomonas axnopodis pv. glycines has been established. Varieties/lines resistant to major diseases have been identified. Trichoderma viride and Pseudomonas fluorescens have been found effective for the management of collar and charcoal rot. A few natural plant products like Lawsonia, Tagetes and Acacia were found promising for the management of Myrothecium leaf spot. 

Management of soybean insect-pests

Integrated Pest Management for soybean has been standardized and demonstrated in farmers’ fields. To facilitate scouting and monitoring, management of spray application, and assessment of likely damage, a month wise calendar of insect-incidence has been prepared. Effective chemical insecticides have been identified and recommended. Microbial insecticides, based on Bacillus thuringiensis and Beauveria bassiana, were found effective for the management of defoliators. On the basis of large scale field screening and laboratory screening, sources for insect resistance have been identified and are being used for developing insect-resistant varieties. 

1.1 Plant Pathological Technology

  • • Twenty-three diseases identified and classified in to major and minor based on their distribution economic significance. Myrothecium leaf spot, Alternaria leaf spot, rust, collar rot, pod and stem blight, anthracnose and pod blight, bacterial pustule, yellow mosaic and no podding syndrome were classified as major.

  • • Yield loss estimation revealed a reduction of 14% by bacterial pustule, 48% by Myrothecium leaf spot, 80% by Indian bud blight, 63% by rust, 51% by Alternaria leaf spot and 36-80% by purple seed stain and 64% by stem and pod blight caused by C. truncatum.

  • • A positive correlation of seed infection category of purple seed was observed with seed coat rupture, number of dead seeds and negative with seedling length, test weight, SSLI germination and number of normal seedlings.

  • • Experiments have proved that bold seeds in comparison to small and shriveled seeds upon seed treatment with thiram and carbendazim resulted in reduced seedling mortality and increased seedling emergence and yields.

  • • Seed borne diseases viz, bacterial pustule, Myrothecium leaf spot, Alternaria leaf spot , purple seed stain, anthracnose and pod blight and other diseases like Indian bud blight and rust severely affected field germination (ranging from 20 to 100%), and per cent loss in seed germination was positively correlated with percent seed borne infection.

  • • Studies on some of the epidemiological aspects of bacterial pustule, Myrothecium leaf spot, Indian bud blight, Alternaria leaf spot and rust have been taken up.

  • • Primary source of rust inoculum for south India is lying in the bank of Krishna River and its tributaries in the districts of Kolhapur, Sangli, Satara and Belgaum. Self-sown and winter-sown sole or intercrop soybean in irrigated areas might be harbouring rust pathogen in off-season and acting as a source of primary inoculum for rainy season soybean crop. There may be little or no role of collateral hosts in the initiation of rust. Four hot spot areas in Maharashtra and Karnataka have been identified where rust appears first and from here rust spread to other areas. Study clearly indicated that it is not the amount of rainfall but high relative humidity and congenial temperature, which are the main guiding factors for the onset and spread of rust. Study involving differential hosts and morphological parameters of urediniospores indicated presence of different races of rust.

  • • Species of Colletotrichum, Septoria, Fusarium and Alternaria were found associated with cotyledonary spots.

  • • Forty two isolates of Sclerotium rolfsii classified in to 6 groups based on cultural characteristics, sclerotial formation and morphology, and pathogenicity.

  • • Sixty-five isolates of Xanthomonas campestris pv glycines from different agroclimatic zones of India were isolated and twenty out of them were characterized on physiological and biochemical basis.

  • • On the basis of pathogenicity 15 isolates of Colletotricum truncatum isolated from different agroclimatic zones were grouped into six pathotypes .

  • • DNA has been isolated from the different isolates of C truncatum.

  • • The growth of Sclerotium rolfsii in the medium containing sulphur, zinc, copper, iron, manganese and calcium was better. A pH of 6.5 and 350C temperature was most favourable for the growth and formation of sclerotia. Soil amendments with cotton oil cake, farmyard manure, biogas slurry and soya de oiled cake were promising in reducing pre-and post-emergence mortality caused by Sclerotium rolfsii

  • • Multiple disease resistant lines/varieties like PK 262, PK 327, PK 471, PK 695, PK 1169, PK 1243, PK 1251, SL 432, SL 459, SL 517, SL 528, TS 99-128, JS 71-05, JS 72-280, JS 75-46, JS 76-206, Bragg, Punjab 1, MACS 58, MAUS 52-1, VLS 2, Monetta, JS (SH) 91-33, JS(SH) 93-01, Himso 1569, NRC 35, NRC 41, NRC 44, RAUS-3, RSC 1, RSC 3, AMS 243, AMS 358, AMS 56, JS 20-29, SL-958, MACS 1336, DS 2614, DS 12-13, PS 1042, SL 688, JS 20-69, JS 20-89, SL 955, SL 983, MACS 1410, MACS 1407 and RVS 2002-4 have been identified.

  • • Rust resistant/tolerant varieties/lines like, PK 1024, PK 1029, JS 80-21, C3P27, JS 90-225, PK 1197, RSC 2, EC 389170, EC 389178, EC 241778, EC 241780 and and DSb 21, DSb 23-2, Phule Kalyani and KDS 726 have been identified.

  • • Varieties/lines resistant to bacterial pustule including germplasm lines viz. EC 389150, EC 389164, EC 390981, EC 390989, EC 390975, EC 390976, EC 390977, EC 391152, EC 391172, EC 391181, EC 393222, EC 393223, EC 393225 and EC 393237 have been identified. Similarly varieties/lines resistant to myrothecium leaf spot, collar rot, soybean mosaic, Indian bud blight have been identified.

  • • On the basis of multi-year and multi-location screening AMS 243, AMS 358, AMS 56, JS 20-29, SL-958, MACS 1336 were identified as potential sources for resistance to Charcoal rot and DS 2614, DS 12-13, PS 1042, SL 688 for RAB & YMV.

  • • Intercropping with maize and sorghum and pearl millet in 4:2 ratio, sowing up to 10th July, spacing of 30 to 45 cm and plant population of 4 lakh plants/ha found promising with less seedling mortality and higher yields. However, with pigeon pea incidence of collar rot increased.

  • • Seed treatment with carboxin + thiram @ 2 g or thiram and carbendazim in the ratio of 2:1 @ 3g/kg seed found very effective for the control of seed and seedling diseases. Result of seed treatment was also encouraging on seeds of poor grade and ungraded seeds. Seed treatment 50 days prior to sowing was found much more effective than at the time of sowing.

  • • Seed treatment with biocontrol agents viz. Trichoderma viride and Pseudomonas fluorescens increased seedling emergence, plant population and reduced pre and post emergence mortality. Consortium of three strains of T. harzianum was also quite effective for the management of charcoal rot and collar rot.

  • • Seed treatment plus soil application of zinc and boron plus irrigation at the time of pod formation was quite effective for the management of charcoal rot

  • • For the management of foliar diseases two sprays of carbendazim or thiophanate methyl and for rust hexaconazole, propiconazle, triadimefon and oxycarboxin (0.1%) were found effective.

  • • Foliar sprays of carbendazim and mancozeb at R2 and R6 stage increased seed germination and reduced seed borne fungi.

  • • A method was develop to use agrowastes for mass multiplication of bio-control agents Trichoderma.

  • • Trichoderma spp was found to be compatible with seed dressing fungicides like vitavax and thiram

  • • A web-based soybean disease symptoms, identification and management system has been developed.

1.2 Entomological Technology

  • • An insect map, depicting major insect-pests at different AICRPS centres has been prepared. 

  • • A month wise (July to October) calendar of incidence of insect pests has been prepared to know the seasonal incidence of different insect-pests. M Three insects viz. white grub (Holotrichea consanguinea), spotted bug (Euscarcoris ventralis) and stink bug (Plautia fimbriata), were reported for the first time feeding on soybean in this region. 

  • • A prototype, Vertical Beat Sampling Tray, has been developed for easy, efficient and precise sampling of insect pests harbouring in soybean crop. 

  • • IPM packages for major insect-pests have been developed and demonstrated, which give yield advantage of 4.79 q/ha over farmers’ practices and have ICBR of 4.01.  

  • • Suitable and effective insecticides were identified and recommended for the management of major insect-pests, through soil application, foliar sprays or seed treatment: 

    S.No. Name Dose
    1 Bacillus thuringiensis 10 kg/ha
    2 Phorate 10 G 10 kg/ha
    3 Profenofos 50 EC 1.25l/ha
    4 Quinalphos 25 EC 1.5l/ha
    5 Chlorantraniliprole 18.5 SC 100ml/ha
    6 Ethion 50 EC 1.5l/ha
    7 Thiacloprid 21.7 SC 650ml/ha
    8 Indoxacarb 14.5 SC 300ml/ha
    9 Thiamethoxam 30 FS 10ml/kg seed
    10 Triazophos 40 EC 800 ml/ha
    11 Imidacloprid 48 FS 1.25 ml/kg seed
    12 Betacyfluthrin 8.49% + Imidacloprid 19.81% OD 350 ml/ha

  • • Impact of insect and disease control methods was studied, and it was concluded that additional yield to the tune of 12.50 %, 26.89 % and 32.33 % can be obtained by controlling diseases alone, insects alone and diseases and insects both respectively. 

  • • Potential donors for insect resistance have been identified through large-scale field screening of germplasm and advanced breeding lines, e.g. TGX 855-53D, TGX 1073-55E, DS 396, EC 34500, EC 39739, EC 109545 (against defoliators), and L 129, L 592 (against girdle beetle). Some of the lines showing multiple insect resistance were also identified. Subsequently, promising lines were also evaluated for yield and yield contributing characters. Lines so identified, have been included in variety development programme of the Institute. Wild soybean (Glycine soja) was found to be highly resistant to stem fly and girdle beetle. 

  • • Suitable parameters for field screening for resistance to defoliators and girdle beetle have been identified and techniques standardized. 

  • • For the first time, radiation induced resistance to stem fly Melanagromyza sojae, coupled with high yield and early maturity was reported. 

  • • Potential naturally occurring bio-control agents were identified:  

    1. Parasites: Brachymeria spp., Appenteles spp. and an unidentified dipterous larval parasite 

    2. Predators : Rhinocoris fuscipes, Cantheconidia furcellata, Chrysopa carnea, Dragon fly and Spiders 

    3. Insect pathogens : Beauveria bassiana, Noumeria (Spicaria) rileyi, Bacteria and Virus  Maximum activity of bio-control agents, especially parasites was observed during 2nd week of August causing up to 16-20 % parasitisation.  High humidity conditions were congenial for entomo-pathogenic fungi (Beauveria bassiana and Nomuria rileyi) infection in green semilooper and tobacco caterpillar larvae. 30 to 40 % larval mortality was recorded due to B. bassiana and N. riley

  • • Extracts of Annona and Ipomoea leaves was found to have contact toxicity to Spodoptera litura as they damaged the cuticle, extracts of Lantana, Nicotiana, Pongamia and seeds of Acacia, Annona and Datura were found to have stomach toxicity as they damaged the mid gut epithelial layer and peritrophic membrane and extracts of Acacia, Datura and Eucalyptus were found to have both contact as well as stomach toxicity as they exhibited both types of symptoms.

  • • Most suitable combinations of insecticides and herbicides were identified for different situations of insect-pest and weed incidence. Tank-mix application of Chlorantraniliprole 18.5 SC @ 100 ml ha + Imazethapyr 10 SL @ 1.0 l/ha at 15-20 DAS was highly effective in suppressing populations of major insect-pests and incidence of both monocot and dicot weed flora.

  • • Management of Spodoptera litura and semiloopers through entomopathogenic nematodes (Heterorhabditis indica and Steinernema carpocapsae) was demonstrated successfully. The mortality caused by EPNs was comparable with that by Bacillus thuringiensis and chemical insecticide- Quinalphos.

  • •Yield losses due to major insects (defoliators, girdle beetle, pos borer and stem fly) at varying levels of infestation / damage at different crop stages were enumerated.

  • •Anethum graveolens (Suva) was successfully used as a trap crop for managing the larval population. Row combinations of 12:1 and 12:2 were very effective and economical management of soybean defoliators.