Citrus greening disease is one of the established causes of citrus decline in tropical and subtropical areas of the world, including Pakistan. Citrus greening disease is being recognized based on its characteristic symptoms in the field. Symptomatology and Iodo-starch test are the parameters for rapid disease indexing in the field and laboratory and are also helpful for disease mapping. A study was carried out to record the incidence and severity of citrus greening disease within the area of new citrus plantations of Layyah district, including the tehsils viz., Layyah and Karror. The Layyah tehsil showed an incidence of 18%, while Karror showed an incidence of 5.5%. Among the cultivars, the highest disease incidence was attributed to Kinnow (Citrus nobilis x C. deliciosa) at 33% followed by Mosambi (C. sinensis) at 16% and Feutrall’s early at 5%. The highest disease severity was recorded at Layyah with 22.2%. The lowest was observed at Karror with 13.3%. Among the cultivars, Kinnow showed the highest severity, ranging from 27.22% to 36.6% and the least disease severity was recorded in Feutrall’s early of 8.3% at ± 0.05 level of significance. The present study not only helped establish the relationship between the symptomology and quick indexing of disease through iodo-starch test but also provided information through disease mapping in the new citrus plantation of Layyah district for the first time
Since new fungicides are scarce in the market and because of environmental problems, researchers are now emphasizing other alternatives, such as the genetic potential of plants, resistance against pathogens, and the use of biotic and abiotic agents to develop induced or acquired resistance.We investigated the role of resistance-inducing substances (chemicals and plant extracts) in three chickpea cvs.C-44, Pb-91, and Bittle-98 in field experiments against Ascochyta blight disease.These cultivars were selected on the basis of better yield potential shown in previous experiments.Aqueous solution of salicylic acid (SA) at 0.5, 1.0, and 1.5 mM; acibenzolar-S-methyl (ASM) at 0.4, 0.8, and 1.2 mM; and KOH at 25, 50, and 75 mM were applied, whereas Azadirachta indica A. Juss., Datura metel L., and Allium sativum L. plant extracts were applied at 5, 10, and 15%.Disease reduction data was recorded at different intervals from 4 to 14 d after being induced and inoculated with the pathogen.Overall results revealed that significant disease reduction (79.3%) was provided by ASM in the cv.C-44 at 1.2 mM compared with SA, whereas the least significant was KOH.Maximum disease reduction (43.5%) against disease in the plant extracts was observed by applying A. indica leaf extract, but D. metel and A. sativum extracts were not effective.Our findings suggest that enhancing resistance before infecting chickpea plants could be an innovative control method for Ascochyta blight of chickpea.
Total losses in the apples transported from Quetta, Swat and Murree to Faisalabad market during the months of August, September and November were found to be 23, 20 25 percent respectively. In apples kept under the conditions of cold storage for 22 weeks losses were found to be 28 percent. The fungi isolated from rotten apples were Aspergillus niger, A. fumigatus, Alternaria tenuis, A. tenuissima, Cladosporiums herbarum, Helminthosporium tetramera, Mucor racemosus, Penicillium expansum, Pencillium italicum and Rhizopus nigricans. The pathogenecity test revealed that Alternaria tenuis, Aspergillus niger and Rhizopus nigricans were pathogenic to both injury inoculated and non injured inoculated apple fruits. Total losses in banana transported from Nawabshah, Mirpur Khas and Hyderabad to Faisalabad market in the months of December, February and March amounted to 37, 39 and 43 percent respectively. The fungi isolated from rotten banana were Aspergillus fumigatus, Alternaria tenuis , Botryodiplodia theobromae, Colletotrichum musae, and Verticillium theobromae. All these fungi expect A. fumigatus were found to be pathogenic both to injury and non injury inoculated banana fruits.
Abstract A survey was conducted in tomato fields at different localities to assess the distribution of tomato fruitworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) in Punjab Province, Pakistan. The effect of weather factors on its population was also investigated. Eleven tomato‐growing districts were selected and data for larval population and fruit infestation were recorded. The maximum larval population (5.2 larvae/plant) of H. armigera was recorded in Bahawalpur district with 32.6% fruit infestation. However, the minimum larval population (1.4 larvae/plant) inflicted 14.7% fruit infestation in Rawalpindi district. The temperature was positively correlated while relative humidity showed negative interaction with the larval population and fruit infestation.
During a field survey of greenhouses and fresh markets in 2013, fruits of tomato, oranges, and apples exhibited rot symptoms with white mycelial growth and salmon-color sporulation in the vicinity of Sargodha city (32°5′1″ N, 72°40′16″ E), Pakistan. Diseased fruit samples were collected in plastic bags and taken to laboratory on ice for further diagnosis. Diseased fruits were observed under a stereo microscope and single spores were removed using an inoculating needle. Isolation from single spores showed pink to white colonies on potato dextrose agar (PDA) containing hyaline, 2-celled, ellipsoid to pyriform conidia (17 to 24 × 7 to 11 μm) with slanting and truncate basal mark and produced in clusters. Conidiophores were branched (105 to 254 × 2 to 4 μm) and hyphae were hyaline (3 to 5 μm in diameter). These characteristics of the fungus were similar to Trichothecium roseum (Pers.) as reported by Inácio et al. (1). Genomic DNA was extracted by using CTAB buffer from a single pure colony of one isolate of the fungus and PCR analysis was performed for ITS region and part of the 5′ end of the beta tubulin (TUB) gene (2,3). Single fragments of 550 bp and 1.5 kb length from ITS and TUB gene were amplified and sequenced (GenBank Accession Nos. KF975702 and KJ607590, respectively). Sequence analysis showed 99% similarity with T. roseum isolates from different regions of the world. Phylogenetic analysis (MEGA version 5.2 with WAG model) showed the close relatedness to the isolates of T. roseum from Pakistan and isolates from other parts of the world that revealed the low genetic variability of ITS region. TUB gene sequence analysis indicated 100% homology with isolates of T. roseum and to the other species in Hypocreales. Pathogenicity tests were performed on tomato cvs. Nova Mech and Rio Grande, orange cv. Kinnow, and on apple cv. Golden Delicious by inoculating five fruits from each cultivar. Spore suspensions (10 5 conidia/ml of sterilized distilled water) were inoculated into all wounded fruits (9 wounds/fruit) of each cultivar and incubated at 25°C for the development of symptoms. Five wounded fruits of each cultivar were inoculated with sterilized distilled water as a control treatment. The fruits were kept in plastic boxes and incubated in humid chambers for 5 days. The symptoms on apples were observed as brown rot with pinkish spores on rotted tissue. The cross section of apple fruits also showed the brown rotted tissues internally. The fungus developed mycelium and spores on the surface and caused severe rotting inside the tomato and citrus fruits. T. roseum was re-isolated by picking a single spore from rotted tissues of fruits under a stereo microscope, and culturing on PDA. The re-isolated fungus was confirmed morphologically and by molecular techniques. Tomato and apple has been reported as a host for T. roseum (1,4,5) but oranges have not. To our knowledge, this is the first record of T. roseum infecting tomato, oranges, and apples in Pakistan. References: (1) C. A. Inácio et al. Plant Dis. 95:1318. 2011. (2) K. O'Donnell, and E. Cigelnik. Mol. Phylogenet. Evol. 7:103, 1997. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (4) Y. H. Yun et al. Afr. J. Microbiol. Res. 7:1128, 2013. (5) M. Žabka et al. Mycopathologia. 162:65, 2006.
The comparative assessment of density of glandular hairs, population and size of stomatal aperture in chickpea cultivars resistant (R), moderately resistant (MR), moderately susceptible (MS) and susceptible (S) to Ascochyta blight revealed that the density of the glandular hairs on the ventral, dorsoventral sides and population and size of the aperture of stomata were highly significantly different among the four reaction groups. Similarly length of the glandular hairs and area of stomata were significantly different among the four reaction groups. In the resistant reaction group of cultivars, there were higher number of glandular hairs on the ventral, dorsoventral sides and higher number of stomata of leaf as compared to susceptible group. There was no appreciable difference among the population of glandular hairs on ventral side, length of non-glandular hairs and size of stomata of two reaction groups of resistant and susceptible cultivars. The resistant group had the smallest aperture than other groups.
Seed borne mycoflora associated with ten commercial varieties of wheat viz. Blue silver, Faisalabad 85, Manthar-3, Pak 81, Parwaz 94, Pirsabaq 2005, Punjnad-1, Sariab-92, Sh-2002 and Wafaq-2001 was investigated through standard blotter paper and agar plate method by using Mann-Whitney U test. At least eleven fungal genera were recovered from seeds. The most frequently isolated fungi were Bipolaris sorokiniana (11.125%), Aspergillus flavus (9.825%), Alternaria alternata (7.15%) and Aspergillus niger (6.225%). It is apparent from the present investigation that all commercial wheat verities tested were contaminated by fungi. The rolled paper method was used to find out the effect of seed borne fungi on seed germination. Seeds of Pak 81, Wafaq-2001 and Blue silver were germinated in high proportion with variable number of normal and abnormal seedlings than the seeds of other varieties tested. The fungi associated with seeds of wheat cause dire diseases in wheat reducing the germination capacity.
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