NADPH oxidase (Nox) genes are responsible for Reactive Oxygen Species (ROS) production in living organisms such as plants, animals, and fungi, where ROS exert different functions. ROS are critical for sexual development and cellular differentiation in fungi. In previous publications, two genes encoding thioredoxin and NADH-ubiquinone oxidoreductase involved in maintaining ROS balance were shown to be remarkably induced in a highly versus a weakly aggressive Verticillium dahliae isolate. This suggested a role of these genes in the virulence of this pathogen. NoxA (NADPH oxidase A) was identified in the V. dahliae genome. We compared in vitro expression of NoxA in highly and weakly aggressive isolates of V. dahliae after elicitation with extracts from different potato tissues. NoxA expression was induced more in the weakly than highly aggressive isolate in response to leaf and stem extracts. After inoculation of potato detached leaves with these two V. dahliae isolates, NoxA was drastically up-regulated in the highly versus the weakly aggressive isolate. We generated single gene disruption mutants for NoxA genes. noxa mutants had significantly reduced virulence, indicating important roles in V. dahliae pathogenesis on the potato. This is consistent with a significant reduction of cellophane penetration ability of the mutants compared to the wild type. However, the cell wall integrity was not impaired in the noxa mutants when compared with the wild type. The resistance of noxa mutants to oxidative stress were also similar to the wild type. Complementation of noxa mutants with a full length NoxA clones restored penetration and pathogenic ability of the fungus. Our data showed that NoxA is essential for both penetration peg formation and virulence in V. dahliae.

An experiment was conducted in the field laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, to evaluate the efficacy of compost tea and poultry litter extract along with their economic feasibility of their usage in controlling bacterial wilt of brinjal under natural incidence condition. A significant variation was observed among the treatments on the incidence and severity of bacterial wilt in brinjal. The results showed that the lowest wilt incidence was recorded in T₂ (Compost tea as soil drenching), T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application) while the highest wilt incidence was recorded in control treatment in both counting periods. Similar trend regarding the performance of these treatments was observed on the bacterial wilt severity of brinjal. The effects of compost tea and poultry litter extract on the growth and yield parameters of eggplant were observed to be significant. The results revealed that plant height, number of branches per plant, number of fruits per plant and fruit yield per ha were recorded as maximum in T₂ (Compost tea as soil drenching), followed by T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application), while the minimum plant height, number of branches per plant, number of fruits per plant and fruit yield were recorded in control treatment (T₁). The other treatments showed significant effect in increasing all the growth and yield parameters of brinjal as compared to control. Benefit cost analyses (BCR) showed that T₆ (IPM Lab Biopesticide as soil application) resulted in the highest BCR (99.21) as compared to control, followed by T₇ (BAU-Biofungicide as foliar spray) and T₂ (Compost tea as soil drenching) with BCR 35.7 and 19.5, respectively. The results indicated that an investment of Tk. 1.00 may lead to a profit up to Tk. 99.21 by soil application of IPM Lab Biopesticide which gave the maximum profit in the present study. T₇ (BAU-Biofungicide as foliar spray) followed T₂ (Compost tea as soil drenching) where the investment Tk. 1.00 returned a profit of Tk. 35.70 and Tk. 19.5, respectively. Soil drenching of compost tea showed comparatively lower BCR but the highest percent increase of gross margin was obtained when compost tea was applied as soil drench (T₂). Therefore, it may be concluded that soil drenching of compost tea may be an alternative approach to control bacterial wilt of brinjal along with other possible organic amendments.

Huanglongbing (HLB), also known as citrus greening, is the most serious disease affecting citrus production in Asia, Africa, the Americas, and the Arabian Peninsula. HLB is associated with the α-Proteobacteria “ Candidatus Liberibacter asiaticus” ( C Las), “ Ca. L. africanus” ( C Laf), and “ Ca. L. americanus” ( C Lam). The Bangladesh citrus industry comprises mandarins, sweet oranges, pummelos, limes, and lemons. In 2017-2018, a survey was conducted for two consecutive years in 18 sweet orange growing areas of Bangladesh, and the presence of C Las in these areas was confirmed by polymerase chain reaction. HLB incidence and severity were assessed based on leaf symptoms. The results unveiled a widespread prevalence of HLB with incidence ranging between 0.08 and 56% and severity between 1.80 and 28.33. Information on the genetic diversity of C Las Bangladeshi isolates was obtained based on the presence or absence of Type 1 (SC1, NC_019549.1) and Type 2 (SC2, NC_019550.1) prophages. In silico phylogenetic analyses based on Type 1 and Type 2 prophage sequences showed the presence of four and three clusters of C Las isolates, respectively. Combined phylogenetic analyses of Type 1 and Type 2 prophages indicated the existence of four clusters of C Las isolates. Bangladeshi C Las isolates were found to harbor multiple copies of prophages. The diversity analysis revealed different C Las isolates distributed to different citrus growing areas, indicating spread through propagated materials.

A survey was carried out to record the prevalence of the nursery diseases in four mango varieties (Gopalbhog, Langra, Amropali and Seedless) in some selected growing areas viz. Chapai Nawabganj, Rajshahi, Dinajpur and Mymensingh in Bangladesh. Altogether nine different diseases viz. anthracnose, die-back, malformation, scab, powdery mildew, sooty mould, red rust, gummosis and bacterial leaf spot were recorded during the period of survey. All the diseases were found in the nurseries of Chapai Nawabganj, but Gummosis was not observed in Rajshahi, Dinajpur and Mymensingh and die-back was also not found in Dinajpur. Only anthracnose was recorded in Kajla sinduri in Rajshahi and Kancha mithi in Dinajpur. Out of the 40 mango varieties surveyed occurrence of higher number of diseases were recorded in Amropali (9), Mollica (7), Langra (8), Aswina (8), Khirsapat (8), Fazli (8), Vustara (6), Bogra gooti (6), BARI Aam-2 (6), BARI Aam-4 (6), Mohananda (5), Polyembryony (7), Gopalbhog (7), Hybrid 10 (6), Nilambari (6), Mixed special (6) and Seedless (7). The efficacy of BAU-Biofungicide and four different fungicides viz. Amistar, Tilt 250 EC, Bavistin and Dithane M-45 in the nursery of four mango varieties (Gopalbhog, Langra, Amropali and Seedless) were evaluated in FTIP, Department of Horticulture, Bangladesh Agricultural University, Mymensingh. BAU-Biofungicide showed good effect in controlling anthracnose, die-back, powdery mildew, bacterial leaf spot and sooty mould of mango whereas Dithane M-45 was found best for controlling red rust of mango. Dithane M-45 followed by BAU-Biofungicide and Bavistin resulted reduction of powdery mildew incidence over control while the severity of powdery mildew was lowest in Bavistin followed by Dithane M-45 and BAU-Biofungicide.