Potato blackleg is caused by a diverse species of pectinolytic bacteria. In Pakistan, approximately 90% of the pathogens involved belong to Pectobacterium atrosepticum. Survey (2014 to 2017), sampling, and isolation from different potato growing areas of Punjab, Pakistan depicted an overall disease incidence of approximately 15%. Thirty-six pectinolytic strains confirmed through biochemical and pathogenicity testing were characterized via gapA gene to identify them at the species level. To further validate the identification, one strain from each species SS26 (P. atrosepticum), SS28 (Pectobacterium polaris), SS70 (Dickeya dianthicola), SS90 (Pectobacterium parmentieri), SS95 (Pectobacterium punjabense), and SS96 (Pectobacterium versatile) were selected for draft genome sequencing and multilocus sequence analysis of 13 housekeeping genes (fusA, rpoD, acnA, purA, gyrB, recA, mdh, mtlD, groEL, secY, glyA, gapA, and rplB). Phylogenetic analysis revealed considerable genetic diversity in the genus Pectobacterium. In silico DNA–DNA hybridization and average nucleotide identity values of the strains selected for genome sequencing were determined with other reference Pectobacterium and Dickeya strains. Moreover, all six representative strains were also phenotypically characterized on the basis of metabolism of different carbon sources. Overall, on the basis of genotypic and phenotypic characteristics, these 36 isolates were grouped into six species: P. atrosepticum, P. versatile, P. parmentieri, P. polaris, P. punjabense, and D. dianthicola.

Pakistan is among the top 15 citrus producing countries in the world, with an area of 199,000 ha and 19.7 MT annual citrus production. In 2014, a survey was conducted in three major citrus growing areas (Sargodha, Khushab and Bhalwal) of Punjab province, where 94% of Pakistan’s citrus production is concentrated (Tahir, 2014). Severe dieback was observed in orchards, resulting in 40% yield losses. Dead twigs of Citrus reticulata cv. Kinnow produced small black pustules. Other symptoms included leaf chlorosis that eventually affected the whole plant. Samples were collected from twigs of symptomatic plants with more than 40% canopy infection from different orchards. Short segments encompassing lesion margins were excised, surface-sterilized with 70% ethanol, placed on potato dextrose agar (PDA), and incubated at 30 ± 1°C for 3 days with 12 h alternate light and dark cycle. Two different fungal morphotypes were recovered in a 2:1 frequency ratio. To obtain pure cultures, hyphal tips were transferred onto fres...

In screenhouses, foliar and soil applications of induced resistance (IR), nutrient deterrence (ND), and soil amendment (SAM) treatments to canola, Brassica napus L., reduced fitness in an aphid pest, Brevicoryne brassicae L. Effects of different combinations and doses of IR, ND, and SAM on aphids were compared with those of labeled doses of Carbosulfan and a control. Dose differences between treatments and the control were found for several measures of B. brassicae fitness, including Kaplan–Meier functions, reproduction time, effective fecundity (M_d), intrinsic rates of natural increase (r_m), relative growth rate (RGR), and generation time. Progeny, development/pre-reproductive period, and percent progeny nymph survival were also significantly different from the control. Carbosulfan was the most rapidly acting treatment; however, 1 mM salicylic acid (SA) produced statistically significant reductions in aphid fitness compared to the control, followed by 1 mM citric acid (CA), 0.5 mM SA, and 0.5 mM CA. Silicon (Si) at 50 kg/ha was the most effective ND approach. Ammonium sulfate (AS) only decreased fitness at 25 kg/ha. The SAM combinations of both elemental sulfur (ES) and bio-sulfur (BS) treatments with compost (Cp) also yielded statistically significant aphid fitness reductions. These results provide context for future exploration of IR, ND, and SAM approaches to improve canola yield and reduce aphid damage.

Tomato (Solanum lycopersicum L.) is one of the important vegetable crop widely cultivated across the world. In Pakistan, tomato is being cultivated on an area of 159,000 ha with an annual production of 2,901,000 tons (FAO. 2014). In April-May 2014, wilted tomato plants were observed with yellow leaves and yellowish to brown stem coloration that eventually dried to brown were observed in Punjab, Pakistan. Symptomatic plants were easily uprooted and black sclerotial bodies were observed in the lower stems of the infected plants with roughly shredded appearance. Root and stem portions from symptomatic plants were cut into small pieces, surface sterilized with 1% sodium hypochlorite for 3 to 5 min followed by a rinse with sterile distilled water, blotting on filter paper and were transferred onto potato dextrose agar (PDA) amended with chloramphenicol (250mg/L). PDA plates were incubated at 25 ± 2°C for 7 days. Fungal colonies isolated on PDA medium were initially hyaline but later became grey with plenty of ...

Cheapest way to control gram blight is the use of resistant cultivars. Forty-eight genotypes comprising of black and white chickpea cultivars were collected from Ayube Agricultural Research Institute, Faisalabad. Genotypes were sown in augmented design in a way that after every two genotypes of test germplasm, there was a check (spreader) row. Artificial inoculation was used to screen out germplasm. Among 48 lines, 10 and 11 lines showed resistant and moderately resistant response, respectively. Most of the lines showed susceptible to highly susceptible response while others exhibited moderately susceptible. Sixteen lines were highly susceptible and eight were susceptible. Three lines displayed moderately susceptible response. Ranges of percent disease severity on resistant and moderately resistant advanced lines were; 3.75–10 and 12.5–20, respectively. And, these ranges for highly susceptible, susceptible and moderately susceptible genotypes were; 56.25–81.25, 40–45 and 665–752.5, respectively. Maximum and minimum ranges of area under chickpea disease progress curve (AUDPC) for resistant and moderately resistant advanced lines were; 70–192.5 and 210–367.5, respectively. Highly susceptible, susceptible and moderately susceptible genotypes showed AUDPC as 1085–1715, 787.5–910 and 647.5–735, respectively. Resistant and moderately resistant advanced lines had AUDPC 70–227.5 and 245–420, respectively. While, AUDPC values for highly susceptible, susceptible and moderately susceptible genotypes remained as 1172.5–1750, 805–962.5 and 665–752.5, respectively.

Upland cotton (Gossypium hirsutum L.) is the world’s leading fiber crop, and is considered the backbone of Pakistan’s national economy (Hamid et al. 2012). Bacterial leaf blight attributed to Xanth...