Cent Disease Index Research Articles

Selection parameters for downy mildew disease, fruit yield and related traits in ridge gourd [Luffa acutangula (Roxb.) L.

Forty one genotypes of ridge gourd were evaluated in augmented design with three checks. Analysis of variance revealed significant differences among genotypes for all the traits. High PCV, GCV, heritability, genetic advance were observed for number of branches at 45 and 90 DAS, nodes up to first pistillate flower appearance, number of fruits per vine, average fruit weight, fruit length, fruit yield per vine, Per cent Disease Index (PDI) for downy mildew at 45, 60 and 75 DAS and fruit fly incidence. Positive and significant association was observed for fruit yield per vine with vine length at 45 and 90 DAS, number of branches at 45 and 90 DAS number of fruits per vine, fruit length. Fruit yield per vine was negative and significantly associated with days to first male flowering, nodes up to first female flowering, days to first harvest, flesh thickness, days to first appearance of downy mildew symptoms and per cent disease index for downy mildew. In open field screening for downy mildew has led to identification of two resistant genotypes (COHRG-9 and COHB-32), two moderately resistant lines (COHB-10 and COHB-40) and one was highly susceptible (COHB-8) whereas remaining genotypes were exhibited moderately susceptible and susceptible reaction to downy mildew in ridge gourd.

Evaluation of fungicides against sheath blight of rice caused by Rhizoctonia solani (Kuhn.)

Fixed plot survey for sheath blight disease conducted in some major rice growing areas of Cuddalore district, Tamil Nadu indicated that the Per cent disease index (PDI) varied with low to high level. The maximum PDI of 36.5% was recorded in Naduthittu followed by Vadakkumangudi (32.4%), Vallampadugai (26.5%), Muttlur (21.4%) and the least level of incidence was noticed in Ramapuram (10.5%). Four different inoculation methods were tested in the field. Among the four methods of artificial inoculation, sheath inoculum was found to be the best in plant infection. Out of different fungicides screened against the pathogen under in vitro condition, the new chemical ICF 310 at 1000 ppm concentration completely inhibited the growth of Rhizoctonia solani Kuhn, causing sheath blight disease. In pot culture different methods of treatment were applied by using ICF 310 against R. solani, where the fungicide ICF-310 at different levels showed significant influence on the incidence sheath blight of rice. Among the various treatments, combined application of ICF 310 as ST @ 2 g/kg of seeds + ICF-310 @ 0.1% as seedling root dip + ICF-310 @ 0.1% as foliar spray at 30 DAT and 45 DAT recorded the minimum sheath blight incidence (8.99%) at harvest. This was followed by combined application of ICF-310 as seed treatment @ 2g/kg of seeds + ICF-310 @ 0.1% as foliar spray at 30 DAT+ 45 DAT which recorded the sheath blight incidence of 9.45% and the maximum sheath blight disease incidence was observed in untreated control.

Screening Arbuscular Mycorrhizal Fungi in Order to Select the Best for Alleviating Wilt Disease Complex of Capsicum

Arbuscular mycorrhizal fungi (AMF) play an important role in protection of host plant from infection by soil-borne plant pathogens. In the present study different AMF were tested for their ability to alleviate wilt disease complex of tomato caused by bacterial pathogen Ralstonia solanacearum, fungal pathogen Phytophthora capsici and root-knot nematode Meloidogyne incognita. Plant growth parameters like plant height, stem girth, biovolume index, root and shoot dry weight, total plant dry weight, disease index and mycorrhizal parameters like per cent root colonization and spore count in the root zone soil were evaluated. In general AMF inoculation increased plant growth parameters. Among 11 AMF screened, Glomus bagyarajii was found to be the best AMF in enhancing plant height, stem girth, total plant dry weight, mycorrhizal root colonization and most importantly exhibited least per cent disease index (50.20 %) as compared to control (82.14 %). The results show the potential of using G. bagyarajii for the biocontrol of wilt disease complex of capsicum.

GIS mapping and survey for powdery mildew severity on linseed (Linum usitatissimum L.) in Northern Karnataka

Powderymildewoflinseed caused byLeveillula taurica (Lev.) Arn. is one ofthe economicallyimportant disease causing yield loss up to 60 per cent. Survey conducted in Northern Karnataka to assess the severity of linseed powdery mildew during rabi of 2014-15 revealed that mean maximum powdery mildew was observed in Raichur (98.00) followed by Bellari (32.50), Bidar (19.00), Vijayapura (17.66), Koppal (14.00), Yadgir (13.00) and least per cent disease index was observed in Kalaburgi (11.85). During the survey it was observed that the incidence of the disease was maximum in Raichur district, this may be due to the fact that crop coincides with the favourable weather factors such as cold temperature at night and warm days, no rainfall during crop growth period, continuous cultivation of linseed crop in the same area might have provided the primary source of inoculum.

Identification and marker‐assisted introgression of QTL conferring resistance to bacterial leaf blight in cowpea (Vigna unguiculata (L.) Walp.)

AbstractBacterial leaf blight (BLB), caused by Xanthomonas axonopodis pv. vignicola (Xav), is widespread in major cowpea [Vigna unguiculata (L.) Walp.] growing regions of the world. Considering the resource poor nature of cowpea farmers, development and introduction of cultivars resistant to the disease is the best option. Identification of DNA markers and marker‐assisted selection will increase precision of breeding for resistance to diseases like bacterial leaf blight. Hence, an attempt was made to detect QTL for resistance to BLB using 194 F2 : 3 progeny derived from the cross ‘C‐152’ (susceptible parent) × ‘V‐16’ (resistant parent). These progeny were screened for resistance to bacterial blight by the leaf inoculation method. Platykurtic distribution of per cent disease index scores indicated quantitative inheritance of resistance to bacterial leaf blight. A genetic map with 96 markers (79 SSR and 17 CISP) constructed from the 194 F2 individuals was used to perform QTL analysis. Out of three major QTL identified, one was on LG 8 (qtlblb‐1) and two on LG 11 (qtlblb‐2 and qtlblb‐3). The PCR product generated by the primer VuMt337 encoded for RIN2‐like mRNA that positively regulate RPM1‐ and RPS2‐dependent hypersensitive response. The QTL qtlblb‐1 explained 30.58% phenotypic variation followed by qtlblb‐2 and qtlblb‐3 with 10.77% and 10.63%, respectively. The major QTL region on LG 8 was introgressed from cultivar V‐16 into the bacterial leaf blight susceptible variety C‐152 through marker‐assisted backcrossing (MABC).

Management of Major Diseases of Indian Mustard Through Balanced Fertilization, Cultural Practices and Fungicides in Calcareous Soils

Indian mustard, Brassica juncea (Linn.) Czernj and Cosson is ravaged by several diseases viz., Alternaria blight, Sclerotinia stem rot, white rust and nutrient deficiency causing substantial yield loss. A field experiment was conducted on the integrated management of major diseases in Indian mustard through different combinations of balanced fertilization, cultural practices and restricted use of fungicides (as seed treatment and foliar spray) to observe their role in augmenting the seed yield and its attributes in calcareous soil at the Indian Agricultural Research Institute, Regional Station, Pusa, Bihar (India) during 2012–2013 and 2013–2014. Seed treatment with propiconazole plus two foliar sprays of propiconazole at 70 and 80 days after sowing showed lowest per cent disease index of Alternaria leaf blight (2.40), pod blight (8.61), white rust (1.39), Sclerotinia twigs infection (1.90) and Sclerotinia stem rot (8.76) in comparison to other treatments and control during both the years. However, integrated treatments i.e. seed treatment with propiconazole (0.1 %) + balanced fertilization + removal of four lower leaves at 60 days after sowing + one foliar spray of propiconazole (0.1 %) at 70 days after sowing resulted in second lowest severity and incidence of major diseases. This treatment produced significantly highest yield (2339 kg/ha) and its attributes in comparison to control (1050 kg/ha) and remaining treatments. Thus, inclusion of micro and secondary nutrients, cultural practices and restricted fungicidal spray in combination had a beneficial effect on yield enhancement of rapeseed–mustard with substantial reduction in all the major diseases.

Effect of fungicides on the mycelial growth of Alternaria alternata causing leaf spot disease in ashwagandha

A Leaf spot disease was caused by Alternaria alternata ten isolates were collected from the ashwagandha growing different regions of Tamil Nadu. The virulence of the isolates were tested based on the Per cent Disease Index (PDI) and symptom expressed on the foliar surface. The maximum disease intensity of 65.13 PDI was recorded in Chempatti (I 6 ) isolate. The minimum disease intensity was recorded in I 10 from Cumbum (36.83 PDI). Seven fungicides viz., carbendazim(0.05%), mancozeb (0.2%) copper oxy chloride (1%), chlorothalanil (0.2%), fosetyl (0.1%), Ridomil MZ (0.05%) and dithane M 45(0.05%) were tested against A. alternata. Among the fungicides, the minimum diameter of mycelial growth of A. alternata (0.75cm) and maximum percentage of inhibition (91.34%) were recorded in mancozeb (0.2%). How to view point the article : Kalieswari, N., Raja, I. Yesu and Devi, M. (2016). Effect of fungicides on the mycelial growth of Alternaria alternata causing leaf spot disease in ashwagandha. Internat. J. Plant Protec., 9(1) : 153-157.

Survey for purple blotch of onion (Alternaria porri(Ellis) Cif.) in northern parts of Karnataka

Onion (Allium cepa L.) is one of the important bulb crop and most important commercial vegetable crops cultivated extensively in India and it accounts for 90 per cent of the exported vegetables from India in terms of value. The production ofbulbs and seeds is limited by certain diseases. The most serious one is the purple blotch caused by Alternariaporri (Ellis) Cif. The disease causes extensive damage to bulbs as well as seed crop and also a major limiting factor in cultivation of onion. In view of the destructive nature of purple blotch of onion the present investigation was conducted through survey to know the disease incidence or severity and collection of infected samples. A survey was conducted during kharif 2013–2014 in onion growing areas of Northern Karnataka viz., Bijapur, Bagalkot, Gadag and Dharwad districts. The highest per cent disease index was noticed in Ilkal village of Bagalkot district. While, the lowest per cent disease index was noticed in kerur village of Bagalkot district. Among the districts, severity of disease was more in Bijapur and less in Gadag. Isolation was made from onion leaves showing typical purple blotch symptoms. Pure culture of A. porri was obtained and its pathogenicity to onion plants was proved. On the basis of isolation and morphological studies, the pathogen was identified as Alternariaporri (Ellis) Cif.

Occurrence of Diseases on Muga Silkworm Host Plant SpeciesLitsea monopetalaRoxb. Under Prevailing Weather Conditions during Different Seasons in District Bageshwar, Uttarakhand

Muga silk is cultivated through rearing of the insect silkworm Antheraea assamensis Helfer on the leaves of its host plant Litsea monopetala Roxb. under open weather conditions. During the course of development, the host plants of silkworm are found prone to various diseases. The leaves of host plants because of disease infection become unpalatable for the muga silkworms which ultimately affects on quality and quantity of muga silk production. In the present study, during the year 2012 and 2013, a survey on foliar diseases on the muga silkworm primary host plant L. monopetala Roxb. was carried out in District Bageshwar of Uttarakhand, India and recorded greatest foliar damage (FD) and per cent disease index (PDI) because of the diseases that is red rust (Cephaleuros sp.) FD 19.02% and PDI 11.98, leaf spot (Phyllosticta sp.) FD 7.14% and PDI 5.28, brown blight (Colletotrichum gloeosporioides Penz.) FD 11.63% and PDI 7.31% and grey blight [Pestalotiopsis theae (Thuem.) Stey.] FD 9.30% and PDI 7.11% and others during August-October on the host plant species under open weather during respective years.

Effect of Agro-chemicals on Severity of Bacterial Blight and Fruit Quality in Pomegranate

Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae is a wide spread disease affecting pomegranate production and quality of fruit in Punjab. In-vitro evaluation of agrochemicals indicated that blitox at 3000 ppm followed by kodde 2500 ppm successfully managed the disease. A field experiment was also conducted for its management at New orchard, Punjab Agricultural University, Ludhiana during, 2013. Three sprays of the agro-chemicals were done at 15 days interval starting from end June to end July on Mridula variety of pomegranate. Among the various treatments, blitox (0.3%) + streptocycline (250 ppm) proved most effective in reducing per cent disease index, per cent fruit cracking and providing maximum disease control. Quality parameters viz., TSS, acidity, weight, pulp colour, juice weight etc. were also studied. Maximum TSS, fruit weight, juice weight, pulp weight, 100 grain weight and total grain weight were observed in blitox (0.3%) + streptocycline (250 ppm) followed by kodde (0.25%) + streptocycline (250 ppm) sprayed fruits.

Effect of organic amendment on stem canker and black scurf disease of potato (Solanum tuberosum)

: An experiment was conducted at Tuber Crops Research Centre, BARI, Bogra during 2008-2009 to evaluate the organic amendment for controlling the stem canker and black scurf of potato. The different kinds of organic amendments were: T 1 =Poultry refuse (PR) at 4 t ha -1 , T 2 =PR at 5 t ha -1 , T 3 =PR at 6 t ha -1 , T 4 =Mustard oil cake (MOC) at 300kg ha -1 , T 5 =MOC at 500kg ha -1 , T 6 =Neem oil cake (NOC) at 300kg ha -1 , T 7 =NOC at 500kg ha -1 , T 8 =Sawdust burning and T 9 = Control. The experiment was laid out in a randomized complete block design (RCBD) with four replications. The organic amendment significantly influenced the disease incidence, yield attributes and yield of potato. The lowest disease incidence (17.5%) and per cent disease index (9.99) were found in T 3 (poultry waste at 6 t ha -1 ). The minimum russet, deformed and Sclerotia infected tubers were also recorded in poultry waste at 6 t ha -1 . The highest healthy tubers and tuber yield were found in the same treatment. Therefore, poultry manure 6 t ha -1 along with recommended dose of chemical fertilizer can be recommended to produce healthy tubers and maximum tuber yield of potato.

Effect of surfactant on the efficacy of fungicides against purple blotch of onion caused by Alternaria porri

Purple blotch of onion caused by Alternaria porri is an economically important disease. The field trials were conducted during three crop seasons in order to study the effect of surfactant on the efficacy of fungicides because the use of fungicides for the control of purple blotch of onion is less promising due to the waxy and smooth leaf surface, which does not allow the fungicides to spread and adhere properly on the leaves. Chlorothalonil 75 WP (1.5 g/l) and mancozeb 75 (2.0 g/l) when sprayed along with surfactant (0.5 ml/l) showed minimum per cent disease index (5.38 and 7.96%, respectively) and disease incidence (11.80 and 15.47%, respectively) at 15 days after third spray in comparison to chlorothalonil and mancozeb alone where the disease index was 8.93 and 11.52%, respectively, and disease incidence was 15.92 and 20.38%, respectively. The results also indicated that the efficacy of fungicides was significantly increased by adding surfactant from 23.69 to 39.75 and 19.87 to 25.88% in minimizing disease index and disease incidence, respectively, in different treatments when compared with the fungicides without surfactant. Both chlorothalonil and mancozeb along with surfactant showed minimum disease severity (9.72 and 12.36%, respectively) at 15 days after third spray and highest bulb yield (237.70 and 231.96 q/ha, respectively) as compared to both the fungicides sprayed alone. The per cent increase in bulb yield over control ranged from 5.57 to 27.60 in different treatments. The fungicides along with surfactant reduced the per cent disease severity (16.15–24.12) and increased the bulb yield (5.31–9.81%) in different treatments when compared with the fungicides without surfactant. The study clearly demonstrated the potential of surfactant to improve the efficacy of fungicides against purple blotch of onion.

Assessment of losses by foliar blight of wheat (<italic>Triticum aestivum</italic> L.)with reference to tillage option management in plain region of Uttar Pradesh, India

Foliar blight of wheat caused by <italic>Bipolaris sorokiniana, Alternaria triticina, Pyrenophora tritici-repintis</italic> and <italic>Curvularia lunata</italic> are gaining importance especially in North Western and North Eastern plain Zones (NWPZ and NEPZ) of India. The experiment was conducted at main experimental farm N.D.U.A. &.T. Kumarganj, Faizabad (U.P.) by taking two wheat varieties i.e. NW1014 and HUW 234 and three tillage systems i.e. zero tillage, FIRBS (Furrow Irrigated Ridged Bed System) and Conventional tillage. Zero till resulted in higher mean per cent disease index (PDI) with variety HUM-234 in the first and second year, respectively, of 72.50 and 69.44 per cent. Under conventional tillage, however, highest yield and yield contributory characters recorded with combination variety NW-1014 during both the years. Conventional tillage with 41.30 and 42.50 q/ha had non-significantly higher yields in first and second year over zero tillage (38.75 and 40.60 q/ha).

Screening of horsegram germplasm collected from Andhra Pradesh against anthracnose

Twenty-one (21) diverse horsegram accessions collected from various parts of Andhra Pradesh state were screened in greenhouse along with four check varieties against <italic>Colletotrichum dematium</italic>, causal agent of anthracnose disease. Based on Per cent disease index (PDI), one accession, IC470275 was identified as immune and the remaining accessions were either moderately resistant or susceptible. Grid maps generated using DIVA-GIS indicated the areas with highest Shannon diversity index for PDI and highest coefficient of variation recorded for horsegram accessions collected from Anantapur district of Andhra Pradesh. The results also indicated that diverse accessions for reaction against <italic>C. dematium</italic> can be sourced from Anantapur district of Andhra Pradesh.

Management of sunflower powdery mildew caused by Erysiphe cichoracearum DC. with botanicals and natural products

Sunflower is reported to suffer heavy losses because of fungal, viral and bacterial diseases and one of the prominent diseases among them is powdery mildew caused by E. cichoracearum. Recently Powdery mildew is most important limiting factors for production of sunflower in Karnataka. Management of powdery mildew in sunflower was studied in both in vitro and in vivo conditions. Azadirachtin, NSKE, Turmeric (leaf extract), Lantana camara (leaf extract) and Ipomoea carnea (leaf extract) were effective in inhibiting spore germination of pathogen both under in vitro condition at 5 per cent concentration. Similar trend was observed in field condition also with Azadirachtin and NSKE at 5 per cent concentration with least disease incidence of 25.78 and 27.56 per cent disease index, respectively in contrast to 83.33 per cent disease index in control.

Studies on the grain yield loss of Isabgol (Plantago ovata) caused byAlternarialeaf blight

To estimate the losses caused by leaf blight of Isabgol at varied disease intensity levels, field experiment was conducted for two consecutive years i.e., 2008 and 2009 of Rabi season. Different disease of leaf blight were generated through varied inoculum densities on two cultivars, Udaipur local and RI-89, using respective virulent isolates. It was found that the disease severity increased with increased inoculums levels, and a significant reduction in grain yields at all the severity levels was observed as compared to the uninoculated protected (Dithane M-45) control in each cultivar. The disease was more in 2009 than in 2008, yet the trend in reduction in grain yield was similar. In these two years of testing the percent disease index (PDI) ranged from 22.36 to 78.12 resulting into 11.19 to 34.73 per cent reduction in grain yield over uninoculated protected (Dithane M-45) control in Udaipur local cultivar. In RI-89, 17.34 to 71.88 per cent disease index (PDI) resulted into 9.45–30.55 per cent loss in grain yield over uninoculated protected (Dithane M-45) control.

Response of mulberry accessions to major foliar diseases in temperate conditions of Jammu and Kashmir, India

Thirty-three indigenous and 24 exotic mulberry accessions belonging to five Morus spp. originated from seven countries distributed in temperate and tropical climates were observed for their response to two major foliar diseases during 2010 and 2011 under temperate conditions of Jammu and Kashmir, India. Leaf spot and powdery mildew severity (per cent disease index (PDI)) ranged from 0.00 to 74.90% and 0.00 to 59.85%, respectively. Indigenous and exotic accessions responded similarly to leaf spot but, varied too much to powdery mildew. Irrespective of origin, response in ascending order of PDI for leaf spot is M. multicaulis, M. indica, M. alba, M. kayayama and M. bombycis and for powdery mildew is M. multicaulis, M. kayayama, M. bombycis, M. alba and M. indica. Among indigenous accessions, Brentul Kashmir offered highest resistance to both the diseases. Nadigam offered maximum resistance only to leaf spot followed by Himachal local, while Chinarpati followed by Mysore local only for powdery mildew. Among ...

Effect of Plant Extracts on Quality of Khasi Mandarin (Citrus reticulata Blanco) Fruits During Ambient Storage

Khasi mandarin (Citrus reticulata Blanco) fruits were treated with Azadirachta indica, Ocimum sanctum, Aloe barbedensis, carbendazim, A. barbedensis + A. indica, A. barbedensis + O. sanctum, A. barbedensis + carbendazim and control (water). Treated fruits were packed in corrugated fibre boxes and kept for a total period of 28 days at ambient storage (20 ± 2 °C and 65 ± 5% RH). Prominent pathogen associated with fruit rot was identified as Penicillium brevicompactum. The fruit quality during storage was evaluated in terms of disease severity (per cent disease index), inhibition of spore germination (%) of P. brevicompactum, decay loss (%), juice content retention (%), total soluble solids (%), acidity (%), ascorbic acid content (mg/100 g) and sensory scores. O. sanctum-treated fruits exhibited minimum decay loss (3.33%) up to a total period of 28 days which was even less than carbendazim (10%). O. sanctum was also highly effective in inhibiting spore germination of P. brevicompactum (96.5%). Overall acceptability score (7.33) was also high in O. sanctum-treated fruits as compared with other treatments at the end of the storage period.

Efficacy of Antibiotics and Biorational Pesticides against Bacterial Blight of Paddy

In rice, streptocycline at 1000 ppm was effective against bacterial blight under in vitro evaluation, with maximum inhibition zone (25.0mm), followed by streptocycline + Copper sulphate 1000 ppm (24.33mm). Under field studies, streptocycline + copper oxychloride was found best with least per cent disease index. Highest grain yield returns were recorded in streptocycline + copper oxychloride treatment @ 0.025 % + 0.1 per cent followed by bactrinashak @ 0.04 and 0.03 per cent.

Heterosis and combining ability for resistance to powdery mildew in adult melon plants

With 4 tables AbstractTo estimate the heterosis, general combining ability (GCA) and specific combining ability (SCA) for resistance to powdery mildew, 30 F1 hybrids developed in a 6 × 5 line × tester mating design were evaluated both under the greenhouse and field conditions. Predominance of non‐additive variance over additive variance in the inheritance of resistance to powdery mildew was detected. Inbred lines IIHR 681, IIHR 352, IIHR 190, RM 43, IIHR 121 and IIHR 122 demonstrated consistently high and negative GCA effects. There was a strong correlation between GCA effect and mean per cent disease index (PDI) of parent that would permit the use of the mean performance of the parental lines to predict the value of a resulting hybrid. Six hybrids, that is, Arka Jeet × IIHR 122, Punjab Sunehri × IIHR 190, RM 43 × IIHR 121, IIHR 681 × IIHR 616, IIHR 352 × IIHR 616 and IIHR 352 × IIHR 718 which involved one or both the parents with good GCA effects exhibited low mean PDI with negative mid‐parent heterosis and negative SCA effects.