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The etiology of shisham (Dalbergia sissoo) die-back has been a subject of considerable scientific debate for hundred years. No single pathogen species is responsible for die-back outbreaks, making shisham die-back challenging to study. Symptoms of the disease include yellowing, the water-soaked appearance of leaves, thinning of leaves and crown, branch die-back (single or whole), bark splitting, gummosis, and lesion development. Symptomatic shisham were sampled from 117 sites across Pakistan. One hundred and ninety-two fungal isolations were made from 1170 shisham samples and were identified as Ceratocystis sp. and Fusarium sp. based on cultural morphology. Koch's postulates were completed using 23 isolates of Ceratocystis sp. and four isolates of Fusarium sp. on three shisham age groups a) 6-12-month-old nursery seedlings growing under greenhouse conditions, b) 1-3-year-old plants growing under natural field conditions, and c) 10-15-year-old tree growing under natural field conditions. Inoculation with Ceratocystis isolates resulted in typical shisham die-back symptoms. Inoculation with Fusarium sp. did not produce any symptoms alone or in combination with Ceratocystis sp. Four fungicides were evaluated for efficacy against Ceratocystis sp. using in vitro tests and field trials. In in vitro test, propiconazole resulted in the highest level of inhibition (88.88%) at day seven, followed by difenoconazole (84.75%), hexaconazole (81.11%), while benzimidazole (77.73%) was least effective against the tested fungus. The efficacy of these fungicides has declined throughout greenhouse trials conducted in this study. Additionally, these fungicides could not prevent tree loss in trees inoculated with Ceratocystis sp. in the field trials. Thus, shisham die-back continues to be of concern in shisham-growing areas in Indo-Pakistan. However, chemical management and continuing research on the epidemiology of this disease may provide a solution. [ABSTRACT FROM AUTHOR]

Dalbergia sissoo is one of the most economically important trees in forestry, agroforestry, and horticulture. This tree species is severely threatened by dieback. Widespread dieback outbreaks and infestations have drastically destroyed billions of D. sissoo trees. Hence, we attempted to resolve the dieback etiology through phylogenomics associated with D. sissoo mortality. The Ceratocystis species was evaluated using morphologically investigated fungal isolates collected from dieback-affected tissue plants. Based on the symptomatology, we have differentiated dieback from Fusarium wilt and concluded that the Ceratocystis fimbriata sensu lato complex is causing shisham dieback in Pakistan. As the Ceratocystis species complex is a cryptic species complex, we used genomics and phylogenetic analysis for deciphering its evolutionary hierarchical order. The pathogen's operational taxonomy was unlocked with the help of phylogenomics, and it was discovered that isolates from D. sissoo represent a species distinct from the other species in the C. fimbriata sensu lato species complex. The name Ceratocystis dalbergicans sp. nov. has been given to the fungus causing dieback disease in D. sissoo. [ABSTRACT FROM AUTHOR]

Phoenix dactylifera L. (Date palm) is one of the leading perennial fruit crops regarding its nutritional profile, medicinal significance, excellent yields, long life, and high adaptability to diverse climatic conditions of semi-arid and arid regions globally. Eleven major palm-growing districts of Punjab, Sindh, and Khyber Pakhtunkhwa were surveyed for wilt disease assessment on date palms. The date palm plantation was highly affected with Fusarium wilt diseases with 55%, the incidence in Khairpur (Sindh province), followed by Bahawalpur at 47.4% (Punjab Province) and 45% in Dera Ismail Khan (KPK province). Disease severity was recorded as 65% in Khairpur, 55% in Bahawalpur, and 50% in Dera Ismail Khan (Sindh, Punjab, and KPK, respectively). Sixty-three Fusarium isolates were obtained from three hundred and eighty (380) diseased samples, and thirty isolates randomly selected out of 63 were studied for morpho-cultural and microscopic characterization. Morpho-cultural characters, i.e., colony pigmentation, growth pattern, conidia (macro and microconidia), shape, apical cell shape, and phalidies studied, coinciding with typical characteristics of Fusarium oxysporum. Twenty isolates of the Fusarium population were subjected to the ITS region sequence data-based phylogenetic network. The Neighbor net algorithm computed an unrooted phylogenetic network displayed as four branched genetic network that depicted the division of twenty fungal isolates into four groups. F. oxysporum (FMB-FO-PD-011) inoculated onto healthy symptomless detached date palm leaves, seedlings, and suckers under controlled and field conditions showed typical wilt disease symptoms. Hence this study proved that F. oxysporum is the potential cause of date palm wilt in Pakistan. [ABSTRACT FROM AUTHOR]

Shisham (Dalbergia sissoo) dieback disease has been a subject of great economic importance for the last few decades in South Asian countries. This disease prevails across the shisham growing geographical regions in these countries. Shisham dieback disease has been highlighted as a national forest problem in Pakistan. In this investigation, major shisham plantations of Pakistan were targeted for disease surveillance and monitoring. The extent of shisham dieback disease at different age classes of shisham plantations was also quantified. Surveillance data revealed, that shisham dieback disease is present in all surveyed shisham growing areas, including in areas where mild to no shisham dieback had been reported previously. A significant correlation was observed between different environmental variables (temperature (T), rain fall (RF), and relative humidity (RH) and disease development at (P < 0.01). T has negative correlation with RF (r= -0.793) and RH (r= -0.867). Infection prevails in different ecological zones depicted that environment has a minor role in disease development. Shisham dieback disease symptoms gain a seasonal peak from mid-February to end-March and mid-August to mid-October. Plants belonging to different age classes were exhibited different levels of disease incidence (20.95-28-2%). These findings will guide policy making and breeding programs with the goal of successful management of the shisham dieback disease and sustainable production of shisham in Pakistan. [ABSTRACT FROM AUTHOR]

Huanglongbing (HLB) is causing destruction in citrus all over the world. Control of this disease is mendatory to save the citrus industry. Asian citrus psyllid (ACP), the natural vector of HLB causing bacterium is present in abundance in citrus orchards of Punjab, pakistan. Rearing of ACP was conducted in this study for the management strategies of HLB. Citrus orchards of Faisalabad district of Punjab, Pakistan were surveyed for HLB diagnosis and acquisition of ACP from HLB positive citrus trees for ACP rearing in controlled conditions of growth room. ACP was successfully reared at 26±2 °C temperature and photoperiod of 13:11 (Light : Dark) and Candidatus Liberibacter asiaticus was detected by conventional PCR in the plants used for ACP rearing. PCR results confirmed the presence of Candidatus Liberibacter asiaticus with discrete bands having amplicon size of 1160bp, 800bp and 700bp for primer pairs OI1/OI2c, OI2/23S1 and A2/J5, respectively. [ABSTRACT FROM AUTHOR]

Date palm is an important fruit crop of Pakistan with rich economic, social and nutritional values. The Baluchistan province of Pakistan has been well known for date palm cultivation since long. In addition to its long history of date palm cultivation, Baluchistan's geo-political position with Iran and Oman also highlights its position as a rich source of genetic diversity. The present study was aimed to estimate the genetic diversity and population structure of date palm in Makran division (Baluchistan), which is considered as a major groove for production of high quality date palm. A set of 52 microsatellite markers were utilized to analyze the genetic relationship among 61 date palm genotypes. High polymorphism was found with an average polymorphic Information content (PIC) of 0.67 which indicates significant genetic variation in date palm accession under study. A total 387 alleles were scored with an average of 8.23 alleles for each locus. According to the Bayesian clustering approach, the entire population was partitioned into two clusters i.e., Turbat and Panjgur with few admixture lines. The presence of two subgroups corresponded to distinct adaptive behavior of genotypes to different ecological environment. Analysis of molecular variance revealed 80% of the variation within individuals, while 16% was due to differences among individuals and 4% variation was found among populations. Principal coordinate analysis and neighbor joining tree exhibited the same clusters as illustrated in STRUCTURE V.2.2 software. The variation detected through SSR markers supports that Baluchistan region may be another center of diversity for date palm. The genetic diversity information from this study can also be used for future breeding programs, association mapping, gene cloning and germplasm conservation. [ABSTRACT FROM AUTHOR]