They affect the above ground parts, e.g.: leaf, stem and pod anthracnose.
Lesions on stems and pods more clearly defined than those on leaves, grey or brown, slightly sunken with raised dark brown or reddish edge. All vegetative parts, except pulvini, are susceptible during early stages of development; invasion of the tap root of a young plant can lead to death. Elongated dark-brown or black sunken spots with reddish or yellowish margins appear on veins, petioles, stem and pods. Diseased seeds carry the fungus from season to season. Spots on the hypocotyl cause death of the plant. Seedlings show canker on cotyledons. These lesions produce pinkish spore masses during moist weather.
To control anthracnose, the recommended measures are:
Sowing disease-free seed, crop rotation and field sanitation. Treat seeds for half an hour in 0.125% solution of ceresan or 1% oraganomercurial fungicide (Seedex). Dust seedex or captan at 3 g per kg of seed. Additionally, spray Bordeaux mixture 5:5:50 or a copper fungicide at 1 kg in 250 litres of water as soon as the symptoms appear.
Lablab bean is affected mostly by Leveillula taurica var. macrospora. White floury patches are formed on both sides of the leaves and all portions of the above ground parts, which gradually turn brown. The leaves become yellow and die, while fruits either do not set or remain small. It is a seed borne as well as a soil-borne disease and causes serious damage in the dry weather.
Red and black pustules appear on the lower surface of the leaves. Attacked leaves turn yellow and drop off.
The aphid species, viz., Myzus persicae Sulz., Aphis gossypii G. and Aphis craccivora K. did not transmit the virus. The host range of the virus was found to be fairly wide and it infected plants belonging to the families Leguminosae, Cucurbitaceae, Compositae, Solanaceae, Amarantaceae, Chenopodiaceae and Commelinaceae. The dilution end point of the virus was found to be between 1:100 to1:1000 and thermal inactivation point between 40°C50°C. The stability of the virus was found to be low and it loses its infectivity after four hours of storage at room temperature 21°C- 28°C. The virus was found to vary considerably from the other ring spot viruses in its mode of transmission, physical properties and host range. Hence, the virus is considered to be different and reported as a new record in India. Affected leaves turn yellowish green, wrinkled and stiff. Though it rarely kills the plants, the growth is retarded and vines do not bear fruits or deformed pods.
They cause severe growth retardation and characteristic root galls. The symptoms include stunting, loss of yield, reduction in quality of pods; severe deficiency symptoms of some elements, incipient wilting during hot periods of the day, increased susceptibility of foliage diseases of vascular wilts.
A virus disease of Dolichos lablab [Lablab purpureus] characterized by broad, bright yellow patches on the leaves, was first observed in July, 1950, at Poona, and has since been encountered in several other localities, the most seriously affected being Gujrat, Khandesh, and Deccan. The white fly Bemisia tabaci was the only one of the insects tested which proved capable of transmitting the virus from diseased to healthy plants (48 out of 54), the incubation period ranging from 14 to 20 days. Juice inoculation and seed transmission tests did not result in the development of infection. The symptoms of a virus disease of Phaseolus lunatus, also transmissible by B. tabaci [R.A.M., 27, p. 550], are similar to those seen on D. labial). However, in several tests infective white flies failed to transmit the D. lablab virus to 34 P. lunatus plants, while the yellow mosaic virus of P. lunatus was innocuous to D. lablab. Enation mosaic of the latter host, which is sap-transmissible but has not yet been conveyed by any insect vectors, is quite distinct from the present virus, for which the name of 'yellow mosaic of D. lablab' is proposed. Out of 12 plants of a variety manifesting immunity from the disease in the field, only one contracted infection after being fed upon by 20 to 30 viruliferous white flies in glasshouse tests, as compared with all 12 of a susceptible variety.
The virus was found to be saptransmissible. The aphid species, viz., Myzus persicae Sulz., Aphis gossypii G. and Aphis craccivora K. did not transmit the virus. The host range of the virus was found to be fairly wide and it infected plants belonging to the families Leguminosae, Cucurbitaceae, Compositae, Solanaceae, Amarantaceae, Chenopodiaceae and Commelinaceae. The dilution end point of the virus was found to be between 1:100 to1:1000 and thermal inactivation point between 40°C50°C. The stability of the virus was found to be low and it loses its infectivity after four hours of storage at room temperature 21°C 28°C. The virus has been compared and discussed with the ring spot viruses reported from other countries. The virus was found to vary considerably from the other ring spot viruses in its mode of transmission, physical properties and host range.Hence, the virus is considered to be different and reported as a new record in India.
In Dolichos lablab infected with Dolichos enation mosaic virus (DEMV) symptom expression is more severe in winter than in summer, while relative virus concentration, assayed serologically, is higher in summer than in winter. The virus concentration reaches its highest peak on the 8th day after inoculation in the first trifoliate leaves that emerge after inoculation of primary leaves, thereafter reaching the lowest concentration on the 10th day in all the leaves. Respiration is higher in the infected leaves during the initial increase in the relative virus content. But when the concentration of virus is highest (on the 8th day), the rate of oxygen uptake is significantly lower than in the healthy controls. Thus the sudden decrease in the virus concentration on the 10th day is preceded by a low rate of respiration on the 8th day, when the RQ also is much lower in the infected tissue than in the corresponding healthy controls.
Dolichos enatiion mosaic virus (DEMV) infection decreased the levels of total carbohydrates and reducing sugars in roots and nodules of D. lablab after 24 days of growth. However, the total nitrogen content in these nodulated virus infected plants was more than that in the healthy plants. Again nodules of virus infected plants contained higher amounts of total nitrogen after 24 days. There was a higher rate of transfer of fixed nitrogen from nodules to the tops and roots on virus infection of the host. Soluble proteins, total soluble nitrogen constituents and the total insoluble nitrogen increased in nodules following virus infection of the legume. Nitrogen fixation in infected plants increased during 24 to 31 days to levels higher than that in healthy plants and this high level was maintained throughout growth period. An increased nitrogen fixing activity by symbiotic rhizobia in nodules of D. lablab following DEMV infection is indicated.
Lablab plants inoculated with Pythium species and Fusarium species separately also developed the wilting symptoms. Another interesting observation noticed was young Lablab plants of 10, 30 and 45 days of age were not infected by these fungi and matured plants of more than 90 days in the flowering and pod setting stage alone were vulnerable to this disease.
The fungal species involved in this study were identified as Pythium middletonii Sparrow., P. aphanidermatum (Edson) Fitzpatrick and Fusarium solani (Mart) Sacc. These fungi were reported to cause stunting and severe wilting of peas 6 weeks after sowing. But these two in combination caused rotting of the cortex tissue in the collar region and wilting. However, no stunting symptom was observed.
248 Dolichos [Lablab purpureus] accessions tested, 1188 and 1374 showed only mild to moderate symptoms. The others were severely affected.
Whiteflies (Bemisia tabaci) transmitted yellow mosaic, yellow vein mosaic and leaf curl diseases of economically important crops. Horsegram yellow mosaic virus and cowpea mild mottle virus have been isolated and characterised in India. Except these two viruses the causal agents of other whitefly transmitted diseases are not known.
Three saponins with molluseicidal and fungicidal activities have been isolated from the roots of Dolichos kilimandscharicus. They were shown to be the 3-O-β-d-glucopyranosides of hederagenin, bayogenin and medicagenic acid.
The length and fresh weight of shoot and root of D. lablab var. lignosus decreased as the inoculum density of M. incognita was increased from 1010,000 larvae per 500 cc soil. Significant reduction in plant growth occurred at the 100 nematode inoculum level and final nematode population was greatest at the 100 level. Of 18 lines of D. lablab evaluated for resistance in pot experiments: ILO28, ILO29, ILO33 and ILO1949I were resistant. ILO26, ILO30 and ILO1949III were moderately resistant, while the rest were susceptible.
Similar symptoms have been reported from Pune and whitefly, Bemisia tabaci Genn, has been established as a vector of the disease agent. This paper, however, contains the information on the transmission of the disease agent and type of particles associated with the disease. For whitefly transmission, the method detailed earlier was used for acquisition access feeding (AAF) and inoculation access feeding (IAF). The whiteflies were allowed AAF of 24 h followed by an IAF of 96 h. Tests were carried out by using D. lablab both as donor and recipient host. Twenty to twentyfive whiteflies were used per test plant. Insects were killed by spraying an insecticide after IAF and plants were transferred to insect-proof glass house for 57 weeks after inoculation in the manner described earlier.
D. lablab plants showing typical yellow mosaic symptoms were harvested 4 weeks after inoculation with whiteflies and homogenized with 0.1 M phosphate buffer, pH8.0 containing 1% 2mercaptoethanol and 0.01M radiumethylenediaminetetraacetate (1:3). The extract was squeezed through cheesecloth, clarified at 8,000 rpm per 20 mt and 4% polyethylene glycol (PEG) and 1.5 % sodium chloride were added. The mixture was incubated at 4°C for 3 h and centrifuged at 10,000 rpm for 20 mt. The pellets were suspended in 0.01 M phosphate buffer, pH 7.5. The suspension was clarified at 8,000 rpm per mt., stirred with 2.5% Triton x -100 for 1 h at 4°C, and centrifuged at 35,000 rpm for 2 h in a Beckman Ti 45 rotor. Pellets were suspended in 5 ml PB, centrifuged at low speed (10,000 rpm) for 10 mt and finally at high speed (40,000) for 2h in Beckman SW 50.1 rotor. The pellet was suspended in 2 ml of buffer and subjected to a low speed centrifugation for 10 mt at 8,000 rpm. Linear sucrose gradients (1040%) were prepared in 0.1 M phosphate buffer, pH 7.0 containing 0.001 M EDTA. The partially purified preparation (0.5 ml) was layered on the gradients and centrifuged at 40,000 rpm for 2.5 h in a Beckman SW 50.1 rotor. Two distinct light scattering bands observed were collected and concentrated by pelleting at 40,000 rpm for 2 h. The samples thus obtained were stained with 2% Uranyl acetate (pH 4.0) and examined under a Philips 410 transmission electron microscope. Particles were measured with a x 7 Bauch and Lamb magnifiers directly from negatives.
Electron microscopy of the sample obtained in the upper band revealed the presence of 12-nm particles, whereas 20 x 40 nm geminate particles were found in the lower band. However, the intact geminate particles were only a few in number (1 or 2 particles per field) but most of the particles appeared to be degraded. The smaller number of geminate particles may be due to their susceptibility to the 2 % Uranyl acetate used for staining, as gemini viruses have been reported to be very susceptible to negative stains. Particles of 12nm appear to be phytoferritins.
Whiteflies transmitted the disease but at a very low transmission rate (2/50). These findings confirm the earlier report, where only 3% transmission of the disease was achieved by B. tabaci. The yellow mosaic disease agent exhibits the characteristics shared by some suspected or proven gemini viruses group members including whitefly transmissibility and particle morphology. The gemini viruses may be responsible for the yellow mosaic in Dolichos lablab. However, for unequivocal proof of their involvement in the disease, an extensive investigation is needed.
The most common pathogenesisrelated protein in this hostvirus combination average kDa in MW and an additional 6 bands (1624 kDa) were also detected. In the range 2445 kDa, a further 3 proteins were present in infected samples. Seven proteins were present in both diseased and healthy samples, but their concentrations were much lower in healthy than in diseased tissues.
Isolates DL-4 and DL-R were obtained from dolichos (Dolichos lablab L.) in Nanjing Agricultural University.DL-4 properties: 12 species of 4 families out of 25 species of 6 families’ plants could be infected by sap inoculation. Myzus persicae and Aphis craccivora failed to transmit DL-4 in non-persistent manner. Its physical properties in crude sap were thermal inactivation point 50-60℃, dilution end point 10-2-10-3, and longevity in vitro 2 days. The viral particles were isometric, 28-30nm in diameter. The UV absorbance of OD 260/280 was l.66. DL-4 gave positive reaction with CMV-Y antiserum in 3 kinds of immuno-logical tests. On the basis of these characteristics, DL-4 was identified as cucumber mosaic virus (CMV). DL-6 properties, Soybean, broad bean could be systemically infected by sap inoculation. DL-6 could cause chlorotic lesions on inoculated leaves of Chetopodium amaranticolor and lesions on bean (Top crop). DL-G was easily transmitted by Myzus persicae. Aphis craccivora in a non persistent manner. Its physical properties in crude sap were, thermal in activation point 60-65℃, dilution end point 10-2 -10-3, and longevity in vitro 2-4 days. The average length of flexuous particles was 764nm. Pinwheel and boundle infusions were found in the cytoplasm of leaf tissues of infected dolichos. DL-6 could produce reaction with SMV antiserum in 3 kinds of immunological tests. According to these characteristics, DL-6 was identified as soybean mosaic virus (SMV).
Reproduction of Meloidogyne javanica on Crotalaria juncea, PI. 207657 and cv. Tropicsun, Sesamum indicum, Dolichos lablab and Elymus glauca was assessed using a root gall index, a reproductive index obtained by dividing the final population of juveniles (J2) in the soil by the initial J2 population (Pf/ Pi), and the number of J2/g of root recovered from roots by mist chamber extraction. Lycopersicon esculentum (cv. Uc. 204C) was included as a susceptible host. The root gall index and soil reproductive index were poor indicators of the host status of our test plants as compared with mist chamber extraction of J2 from roots. Lycopersicon esculentum had a mean root gall index of 7.8. Some plants of S. indicum and E. glaucus had a few galls and other plants had none, with mean root gall indices of 1.6 and 0.8, respectively. No galls were observed in C. juncea and D. Lablab. Lycopersicon esculentum had the highest mean soil Pf/ Pi value (mean=1.93), while in C. juncea and some replicates of S. indicum no soil J2 were found. Even though some replicates had no galls, all replicates supported nematode reproduction. The mean numbers of J2 per gram of root after 5 days of mist extraction were 447.7, 223.3, 165.5, 96.9, 42.3 and 41.9 for D. Lablab, L. esculentum, E. glaucus, S. indicum and C. juncea PI 207657 and cv. Tropicsun, respectively. Accurate assessment of nematode resistance was influenced by sampling time and the nematode extraction techniques used. Individual plants of both C. juncea and S. indicum supported nematode reproduction to some extent, however, both C. juncea and S. indicum have potential as cover crops to reduce M. javanica numbers.
Ninety nine varieties from Uttar Pradesh were screened for their reaction to Alternaria leaf spot. Cultivars including Arka Vijay, JDL 77, Pusa Early Prolific and Rajani were found to be resistant and Arka Jay, Culture 6802, 7103, HA3, HD1, 81, JDL 85 and Kalyanpur Type 2 were found to be highly susceptible.
The dark green watersoaked lesions may appear on any of the above ground parts of infected plants. They enlarge and coalesce if humidity is high. Older lesions are brown and papery, especially on the pods. In badly infected pods the seed may be covered with bacterial slime, and the organisms may penetrate the seed by way of the funicle and micropyle (7:214).
The bacteria (Pseudomonas pisi) are carried and may over winter on and within the seed, where they remain viable for at least 10 months. The pattern of local spread suggests that the organism travels in drainage water. Water droplets on plant surfaces probably also play a part, as infection takes place through both wounds and stomata.
Field experiments were conducted during Kharif seasons of 1993, 1994 and 1995 to find out the efficiency of native isolates of Rhizobium phaseoli in increasing the yield of Katargam Papdi, one of the most popular vegetable grown extensively in South Gujarat. Four isolates were tested with recommended dose of N i.e., 20 kg N ha-1 and compared with half dose and no nitrogen. From three years pooled data, seed bacterization of bean variety Katarganm Papdi with R. phaseoli isolate KBRN-2 @ 200 g culture 10 kg-1 seed without nitrogen fertilizer (ICBR 1:3.53) was found significantly superior for obtaining higher green pod yield with better economic return in South Gujarat.
Aspergillus flavus is a fungal pathogen of maize causing an important ear rot disease when plants are exposed to drought and heat stress. Associated with the disease is the production of afflatoxins, which are a series of structurally related mycotoxins known to be carcinogenic. Previous research has suggested that the alphaamylase of A. flavus promotes aflatoxin production in endosperm of infected maize kernels. The report here is about the isolation and characterization of a 36 kDa alphaamylase inhibitor from Lablab purpureus (AILP). AILP inhibited the alphaamylases from several fungi but had little effect on those from animal and plant sources. The protein inhibited conidial germination and hypral growth of A. flavus. The amino acid sequence indicated that AILP is similar to lectin member of a lectinarcelinalphaamylase inhibitor family described in common bean and shown to be a component of plant resistance to insect pests. AILP also agglutinated papaintreated red blood cells from humans and rabbit. These data indicate that AILP represents a novel variant in the lectin arcelin alpha amylase inhibitor family of proteins having lectinlike and alphaamylase inhibitory activity.
Characteristic symptoms of the disease are bright yellow mosaic patches on leaves with significant yield reductions. A sample from the DYMDaffected Dolichos plants was collected from Mysore (Karnataka) in India in February 2004. The putative virus was transmitted by the whitefly, Bemisia tabaci from Dolichos to Dolichos
Total DNA was extracted from the symptomatic leaves and used to PCR- amplify a begomovirus DNA A Component using degenerate primers (Muniyappa et al., 2003). Sequence generated from this PCR product was used to design virus- specific primers to obtain full length DNA-A clones. The sequence of one clone was determined to be 2760 nucleotides in length and to be most similar to the sequences of DOYMV- (Bangladesh) (AY 271891) and a further clone of DOYMV originating from India (AY 309241) at 95.2% and 93.4% sequence identities, respectively. The number and arrangement of open reading frames on DNA-A were similar to viruses of the genus Begomovirus (family Geminiviridac) originting from the Old World. Attempts to identify DNA-B and β components by PCR (Muniyappa et al., 2003; Briddon et al., 2002) were unsuccessful.
Phylogenetic analysis shows that the three DOYMV isolates to form a sister clade to the mungbeaninfecting begomoviruses which together cluster separately from begomoviruses infecting other hosts in the Indian sub-continent. DOYMV has only 62.963.8% identity with mungbean viruses and lower sequence identities with other begomoviruses (61.063.9%). These results show that, on the Indian sub-continent, Dolichos is infected by a distinct species of begomovirus.
Experiments were conducted in 2004 and 2005 to evaluate the reaction of Lablab to southern root-knot nematode (Meloidogyne incognita). Lablab breeding lines and the check cultivar Rongai were inoculated with southern root-knot nematode, evaluated and compared to Iron and Clay cowpea (Vigna unguiculata) under greenhouse conditions. In 2004, average gall scores (0 to 5 with 5 = severe galling) ranged from 1.3 to 4.7 for Iron and Clay cowpea and T x 41.97 Lablab, respectively. Average nematode egg production ranged from 410 to 33,639 eggs per g of root fresh weight of Iron and Clay cowpea and T x 41-97, respectively. The best Lablab line was T x 3503 with 2.3 gall score and 6696 eggs per g of root fresh weight. One plant of T x 3503 was noted with no galling and only 26 eggs per g of root fresh weight. In 2005 revaluation, T x 3503 was again the best Lablab line with a gall score of 1%. In the 2005 study, Rongai had the most severe galling of all the lines evaluated.
Dolichos yellow mosaic disease (DYMD) affects the production of dolichos in South Asia. Diseased plants produce characteristic bright yellow mosaic patches on the leaves and early infections cause reductions in yield. The putative dolichos yellow mosaic virus (DoYMV) was transmitted poorly (maximum 18.3% transmission) by the whitefly, Bemisia tabaci. DoYMV has a narrow host range and infected only Lablab purpureus and L. purpureus var. typicum out of the 36 species tested. Virus was detected using monoclonal antibodies in a triple-antibody sandwich enzyme-linked immune sorbent assay and by PCR. Complete DNA-A components of DoYMV isolates from Mysore and Bangalore, South India, were sequenced, but several attempts to identify DNA-B and DNA-β were unsuccessful. DoYMV isolates shared DNA-A nucleotide identities of 92.5–95.3% with previously described isolates from North India and Bangladesh. They were most similar to mungbean-infecting begomoviruses at 61.6 – 64.4% of DNA-A nucleotide identities. Phylogenetic analyses of DNA-A sequences grouped the dolichos-infecting and mungbean-infecting begomoviruses into a distinct cluster away from begomoviruses infecting non-leguminous plants in the Indian subcontinent. Antigenically, legume-infecting begomoviruses were most similar to each other compared with non-legume viruses. Collectively, these results indicate that legume-infecting begomoviruses in the Indian subcontinent belonged to a distinct lineage of Old World begomoviruses.
Out of ten fungicides and two neem fomulations assayed in vitro against Sclerotinia sclerotiorum (Lib.) de Bary causing stem and pod rot of dolichos bean, vitavax, companion, bavistin, score, mancozeb and thiram proved to be the most effective as they inhibited the growth of fungus completely (100%). Among the partially effective one, zineb gave the highest inhibition (88.80%) followed by neem formulations. Fungicides and neem formulations found effective and partially effective in in-vitro test were further evaluated as foliar spray for the management of disease. Corresponding increase in yield was obtained by application of vitavax followed by companion and bavistin. Neem oil proved to be least effective in reducing the disease incidence and increasing the pod yield.
The disease was most conspicuous by causing typical anthracnose symptoms first appeared as regular to irregular shaped small brown to black spots on leaves and petioles. These spots enlarged, forming irregular patches of dead tissue. The central portion of the diseases spot on leaves become dry and papery in nature, detached and fell off to form a characteristic shot hole symptom. On petioles, typical dark black lesions appeared ad elongated brown to black lesions developed which enlarged, coalesced all along the petioles and, caused the sunken and black lesions.
The small black fruiting bodies were observed on infected spots. The conidia of Colletorichum lindemuthianum were hyaline, single celled, oblong, cylindrical with rounded ends or some time with one end slightly pointed. The length and breadth of the conidia ranged from 9.5 -11.5µm x 3.5-4.5 µm. The spore germination on different substrates indicated that maximum spore germination was observed in two per cent sucrose solution (51%) followed by one per cent sucrose solution (35%). The least spore germination was observed in case of distilled water (8%).
Maximum radial growth of fungus was observed on Potato dextrose agar (81.00 mm) followed by Richards agar medium (79.00 mm) and browns agar (72.32 mm). Least growth was observed on Sachs agar medium (60.00). the growth of C. lindemuthianum on Potato dextrose agar produce brownish white, uniform, circular, compact mycelium at periphery but raised in centre, regular and fluffy growth with concentric rings were observed. Richards agar produce whitish brown, uniform, circular, regular and partially fluffy growth was recorded.
Among the carbon sources tested against C. lindemuthianum, sucrose was found to be the best for the growth (82.67 mm) followed by dextrose (80.00 mm). The least growth was observed in citric acid (37.67 mm). Among the nitrogen sources tested, potassium nitrate was found to be the best source of nitrogen (78.33 mm), followed by ammonium nitrate (69 .00 mm), while growth did not occur at occur in ammonium molybdate.
Maximum mean radial growth was observed at a temperature of 280 C (79.33 mm) followed by 250 C (26.67 mm). The least growth was occurred at 150 C (36.33 mm). The C. lindemuthianum reached maximum growth at pH 6(77.33 mm) followed by pH 7 (75.33 mm).
Among the biocontrol agents, maximum inhibition of fungus was observed in Trichoderma harzianum (73.54%) The least per cent inhibition was observed in Basillus megaterium (39.46%). Out of eight fungicides tested, in vitro Mancozeb inhibited 100 per cent mycelial growth at 400 and 800 ppm, whereas least per cent inhibition was observed in case of copper oxychloride (6.72%) at 100 ppm. Among the systemic fungicides, carbendazim recorded cent per cent (100%) mycelial inhibition at all the concentrations of 50, 100, 200 and 400 ppm. Whereas the least per cent mycelial inhibition was observed in case of hexaconazole (84.87%) at 400 ppm.
Three hundred genotypes of Indian bean (Lablab purpureus) were screened against dolichos yellow mosaic virus (DYMV) in both field and artificial conditions during 2005-07. It was observed that the lines "VRSEM 894", "VRSEM 860" and "VRSEM 887" were found to be symptomless against DYMV in both natural and artificial screenings. Hence, these lines may be utilized as resistance sources for developing varieties/lines resistant against DYMV. Another study on the effect of environmental conditions on spread of DYMV incidence revealed that there was significant impact of temperature and humidity on the incidence of DYMV. The maximum per cent incidence was recorded at maximum and minimum temperature of 39.8 and 24.5°C along with relative humidity of 56 and 30.75, respectively.
Three bioagents (Trichoderma viride, T. harzianum and Gliocladium virens) and five biopesticides (Achook, Neemgold, Wannis, Spictaf and Neemazal) were evaluated under in vitro and in vivo conditions against Colletotrichum lindemuthianum. All the three antagonistic fungi caused significant inhibition of mycelial growth, maximum being with T. viride (69.21%) followed by T. harzianum (64.20%). Among the biopesticides tested at four concentrations, Wanis applied @ 1000 µl/ml caused maximum inhibition of 82.12 per cent followed by Spictaf (52.85%). T. viride and Wanis @ 1000 µl/ml were most effective in reducing the seed borne infection. Integration of bioagents with Bavistin showed that disease can be effectively managed with seed dressing either with Bavistin or biopesticide followed by foliar treatment with fungicide or biopesticide.
Investigations of yield loss assessment under glass house conditions due to anthracnose (Colletotrichum lindemuthianum) infection at different stages of plant growth revealed adverse effect on various growth parameters of highly susceptible kidney bean cultivar Jawala as compared to healthy plants. However, seed borne infection and cotyledonary leaf stage infection caused maximum reduction in almost all the growth traits. Yield of dry bean varieties obtained from plants inoculated at different stages of plant growth revealed that the disease caused significant decrease in yield of both the varieties. Marked differences in terminal disease severity at different stages of plant growth were observed with the maximum severity in pod development stage infection in both the cultivars viz Jawala (27.04%) and Local (16.23%). Considerable eduction in the yield of green pods of both the types of beans viz., Contender and Luxmi was observed when inoculated with pathogen at different stages of plant growth.
The aim of this study was to investigate the combined applicability of natural coagulant and solar disinfection for turbid water clarification and inactivation of bacteria. The coagulation ability of Dolichos lablab (Hyacinth Bean) extract was assessed by the use of standard jar test measurements in water with various turbidities. Investigation of Dolichos lablab as a natural coagulant was confirmed by its positive effective coagulation activity. An optimum dose of 200 mg of this coagulant resulted in 68% coagulation activity for clarification of water along with inactivation of bacteria in 60 min. Further clarified water with natural coagulant was exposed to sunlight, which showed 100% inactivation of both Escherichia coli and coliform counts within 2 h, with no subsequent reactivation of growth after 24 h. The disinfected water complied with prescribed World Health Organization guidelines for domestic use, in terms of bacteriological quality.
Dolichos bean, Lablab purpureusL. (Sweet) is an ancient legume widely grown throughout the world for its vegetable or pulse for human consumption or as animal forage or feed. Anthracnose in dolichos bean caused by Colletotrichum lindemuthianum (Sacc. & Magnus) is the most widespread and destructive disease. The disease is prevalent in Dolichos bean growing areas of Karnataka and is considered as a limiting biotic factor for successful cultivation. In the present study, different cultivars of Dolichos bean were used and an intensive roving survey for anthracnose of Dolichos bean was carried out during kharif 2010 and 2011 in major dolichos bean growing areas of Southern Karnataka to get precise information on the distribution and intensity of the disease. The data on survey revealed that the anthracnose severity varied from locality to locality. The average disease severity varied in various locations in different districts owing to varied agro climatic conditions and also different cultivars used. In Southern Karnataka, the disease severity was found more in Mysore district (45.23%), followed by Chamarajanagar (38.12%) and Mandya (32.59%) and the least in Ramanagaram district with 23.86 per cent.
Dolichos bean is an important pulse-cum-vegetable crop. The crop is affected by many fungal diseases viz., anthracnose, early blight, root and stem rot, powdery mildew and rust. Among them anthracnose is an important disease present throughout the world but severe in tropical and subtropical regions. Bean anthracnose caused by Colletotrichum lindemuthianum.(Saccand Magn.) Scriber affects all plant parts viz., stem, pods and seeds. One hundred and ninety five germplasm lines of dolichos bean were screened under field condition for identification of resistance source to anthracnose. Among the genotypes screened for disease resistance, 9 genotypes viz., GLB3, GLB 4, GLB 8, GLB 9, GLB 11, GLB 19, GLB 60 GLB 166 and GLB 167 were found immune, 48were resistant, 83 were moderately resistant, 51 were moderately susceptible, 4 susceptible, but none of the genotype came under highly susceptible category.
Anthracnose disease of dolichos bean caused by the fungus Colletotrichum lindemuthianum is a serious disease in southern Karnataka where the crop is grown during kharif season. Survey conducted during kharif 2010 and 2011 revealed that the disease was prevalent in all the fields surveyed and the per cent disease severity was found more in Mysore district (47.54%) followed by Chamarajanagar (40.71%) and Chikkaballapur (33.95%) and least in Ramanagar (23.58%). Average pod infection was highest in Mysore district (23.87%) followed by Chamarajanagar district (18.43%) and Chikkaballapur (14.31%) and the least in Ramanagar district (8.44%).
The maximum mycelial weight was observed after 12 days of incubation. Maximum conidial germination (42.54%) was observed on 2% sucrose solution. Solid medium like Richards agar, liquid medium like Richards medium and Sabourads medium, temperature of 280C and pH 6.0 were found best for the growth and sporulation of C lindemuthianum. Sucrose as carbon source and potassium nitrate as nitrogen source were found to be the best for growth and sporulation of the fungus.
Out of 400 genotypes screened against anthracnose under field conditions, four genotypes viz., GL 152, 364, 371 and 388 were found moderately resistant, 28 resistant, 209 moderately susceptible and 159 susceptible to anthracnose. Out of legume crops and ten weed species tested for its host range, only two legumes viz., French bean and horsegram were infected.
In vitro evaluation revealed that, carbendazim and carbendazim + mancozeb and manoczeb were found effective. Among botanicals, neem seed kernel extract (NSKE), onion and ginger significantly inhibited cent per cent mycelial growth. Among bioagents Trichoderma viride inhibited the growth of fungus to the maximum extent (92.22%). In the management study carbendazim was found to be effective in control of the anthracnose with maximum BCR.
Anthracnose disease of dolichos bean caused by the fungus Colletotrichum lindemuthianum is a serious disease in Southern Karnataka where the crop is grown during kharif season. In the present investigation, an intensive roving survey was conducted for 2 years during kharif 2010 and 2011 to record the incidence and severity of foliar and pod infection of anthracnose of dolichos bean. Survey of major dolichos bean growing areas of southern Karnataka indicated that the occurrence of disease ranged from 23.36 per cent to 47.54 per cent. The highest average foliar infection was recorded in Mysore district (55.42%) followed by Chamarajanagar (46.55%) and Chikkaballapur (40.81%) districts during kharif 2010 and the least was recorded in Ramanagar district (25.69%). During 2011 highest average foliar infection was recorded in Mysore district (39.67%) followed by Chamarajanagar (34.87%) and Hassan (27.88%) districts and the least was recorded in Ramanagar district (21.46%). Average pod infection was highest in Mysore district (26.68%) followed by Chamarajanagar district (21.42%) and the least in Ramanagar district (9.92%) during kharif 2010. During 2011 also, average pod infection was highest in Mysore district (22.06%) followed by Chamarajanagar (15.44%) and Chikkaballapur (12.78%) districts and the least was observed in Ramanagar district (6.97%).
Thirty F1's of Dolichos bean were screened against Dolichos yellow mosaic virus (DYMV) causing severe yield losses in Indian bean (Lablab purpureus). Initial screening was done under field conditions where coefficient of infection (CI) was calculated for each F1. Among 30 F1's, only five F1's namely HADB-3 X VRSEM-887, HADB-3 X VRSEM-894, HADB-4 X VRSEM-894, Swarn Utkrisht X VRSEM-887, Swarn Utkrisht X VRSEM-894 were found symptomless against DYMV with pod yeild of 2.24, 3.38, 3.34, 4.24 and 3.2 kg/plant; 288, 342, 480, 464 and 462 number of pods/plant; 10.4, 10.86, 9.12, 12.86 and 9.24 cm pod length; 2.54, 2.76, 2.86, 2.76 and 2.62 cm pod width; 0.56, 0.82, 0.58, 0.58 and 0.68 cm pod thickness and 4, 4, 5, 5 and 4 number of seeds/pod, respectively. These symptom-less F1's may be utilized for getting good segregates to DYMV resistance in Indian bean breeding.
Hyacinth bean, Dolichos lablab L. is a common bean. It is a summer growing annual or short-lived perennial fodder legume. Experiment conducted to find out the influence of Bean common mosaic virus on the protein, nitrogen, amino acid content in healthy and diseased hyacinth bean leaves
Dolichos mosaic virus disease is caused by a poty virus is characterised by the symptoms like vein clearing, uneven leaf lamina, twisting of leaves, mosaic mottling, puckering and blistering on newly formed trifoliate leaves of Field bean. The virus is flexuous rods measuring ~750 nm size under Electron microscopy. PCR product of Dolichos mosaic virus CP gene of ~ 340 bp length of the virus was amplified by using BCMV partial CP gene specific primers. The virus was transmitted by both sap and aphids to the cultivar HA- 4 under glass house condition to an extent of 88 to 93 per cent, 72 and 33 per cent respectively by Myzus persicae and Aphis craccivora. The virus was transmitted to an extent of 10.33 per cent through seeds. Per cent transmission of virus was more in early inoculated plants. The optimum AFP and IFP of Myzus persicae was found to be 30 min. and 12 hr. respectively at which gave a maximum of70 per cent transmissionwhen 10 aphids per plant were used. The virus was successfully transmitted to French bean, Lima bean, Soybean and Rice bean. Out of 110 Field bean genotypes were screened, Kadale avare showed moderately resistant reaction in both field and green house condition. Among the Pendal avare genotypes, seven showed resistant, 21 showed moderately resistant, 14 each showed susceptible and moderately susceptible and remaining six showed highly susceptible reaction against DMV.