The effect of cercospora leaf spot caused by Cercospora arachidicola and Phaeoisariopsis personata on quality of groundnut haulm was assessed using official methods of analysis. The respective field experiments were conducted in 2004 and 2005 cropping seasons, while the laboratory analyses were carried out at the end of the seasons. The scale of 1–9 was used to determine severity of infection on randomly selected groundnut plants. The results showed that the year effect was not significant as related to haulm composition. However, severity of the disease was found to affect haulm composition either negatively or positively. Crude fibre, crude protein, fat and dry matter content of haulm were significantly lower in severely infected haulm samples compared to uninfected or less severely infected samples. While ash, moisture content and nitrogen free extracts (NFE) increased with increasing disease severity. The regression analysis showed that crude fibre, crude protein, fat and dry matter content were negatively related to cercospora leaf spot severity, while ash, moisture content and nitrogen free extracts showed positive relationship with increasing disease severity. Since infection by cercospora leaf spot pathogen lowers the quality of groundnut haulm, controlling the disease is necessary to ensure good quality of haulm at the end of the season.

Strawberry plants showing symptoms of leaf spots and petiole lesions were collected from El Qalubya governorate, which is one of the most famous areas that extensively grows strawberry in Egypt. The objectives of this study were to isolate and characterize the causal pathogen of the disease. The isolated pathogen was identified as Paramyrothecium roridum (formerly known as Myrothecium roridum) based on its morphological characteristics and sequencing the partial rDNA internal transcribed spacer (ITS). A pathogenicity test using detached leaf assay revealed that P. roridum is a potential pathogen of strawberry. Symptoms started as small necrotic areas which expanded rapidly to macerate whole leaflets and petioles. In advanced stages of infection, dark olive green sporodochia were clearly distinguished on the infected tissues. Six strawberry cultivars showed different levels of susceptibility to P. roridum. Florida was the most resistant cultivar while Beauty, Camarosa, Fortuna and Sweet Charlie were susceptible. Festival showed a moderate level of susceptibility. An in vitro assay on the effect of the liquid culture filtrate of P. roridum on strawberry leaves showed that the filtrate caused damage to tissues and clear necrotic symptoms were developed. High performance liquid chromatograph (HPLC) analysis on the filtrate of 10 day old P. roridum culture revealed the presence of various mycotoxins. The two major toxins detected were 8-alpha-hydroxyroridin H and myrothecin A in addition to other trichothecenes. Data also revealed the capability of P. roridum to produce polygalacturonase (PG) and cellulase (Cx) enzymes in liquid cultures. The activity of PG was found to be significantly correlated with the age of the growth culture. This is the first record of P. roridum on strawberry in Egypt.

Field trails were conducted to evaluate the economics of controlling cercospora leaf spot of groundnut using different fungicides. The experiments were laid out in a strip plot design with three replications at the Teaching and Research farm of the Department of Crop Protection, University of Maiduguri, sudan savanna of Nigeria during the 2002 and 2003 cropping seasons. Four fungicides namely: Benlate 50 WP, Trimangol 80 WP, Bentex T, and Ridomil 72 WP were applied as foliar sprays at three spray regimes while the control was left untreated. The application of the fungicides led to 20–50% reduction in the disease incidence and 15–22% reduction in disease severity and gave higher yield of seed and haulm than the control. The cost-benefit analysis revealed positive returns per hectare from the use of the fungicides for the control of disease in the study area. Application of Bentex T, for instance, gave 78.13% seed yield increase over the control which translated into a mean (two years) net profit of N52,267.50, N90,905.00 and N138,755.00 Nigerian Naira for one, two and three sprays, respectively, equivalent to $522.675, $909.05 and $1,387.55 per hectare. Even the least effective of the fungicides (Trimangol 80 WP) gave seed yield increase of 62.74% over the control which translated into a mean (two years) net profit of N41,287.50, N68,082.50 and N93,995.00 equivalent to $412.88, $680.83 and $939.95 per hectare for one, two and three sprays, respectively. Three sprays gave 115. 76% increase of yield over one spray and 39.35% yield increase over two sprays. These returns are attractive particularly to the farmers in the study area who grow the high yielding Ex-Dakar groundnut variety which is susceptible to cercospora leaf spot.

The efficacy of Benlate 50 WP (benomyl), Bentex T (benomyl + thiram), Ridomil 72 WP (metalaxyl) and Trimangol 80 WP (maneb) applied as foliar spray in the control of cercospora leaf spot of groundnut in the sudan savanna of Nigeria was evaluated during the 2002 and 2003 cropping seasons. Three spray regimes (once, twice and thrice per season) were evaluated. Strip plot design with three replications was used in setting up the experiments. Ex-Dakar, a cercospora leaf spot susceptible groundnut variety was used as planting material. All the four fungicides significantly reduced the incidence and severity of cercospora leaf spot in both seasons. However, the application of Bentex T significantly better reduced the incidence and severity of the disease than the other fungicides. This was followed by application of Benlate 50 WP. Ridomil 72 WP and Trimangol 80 WP which gave moderate control of the disease. Three sprays with fungicides gave better control of the disease than one or two sprays in the season. The highest seed yield of 1 716 kg/ha and 2 263 kg/ha in 2002 and 2003, respectively, were obtained following treatment with Bentex T. The lowest yield of 962 kg/ha and 1 270 kg/ha in 2002 and 2003, respectively, were recorded from the control plots. Also the highest seed yield of 2 028 kg/ha and 2 672 kg/ha in 2002 and 2003, were obtained following three sprays compared to 939 kg/ha and 1 239 kg/ha in 2002 and 2003, respectively, for one spray in the season. The highest haulm yield of 6 131 kg/ha and 6 722 kg/ha in 2002 and 2003 was recorded from plots treated with Bentex T compared to 4 752 kg/ha and 5 166 kg/ha in 2002 and 2003, respectively, obtained from the control. Haulm yield of 6 355 kg/ha and 7 027 kg/ha in 2002 and 2003 were obtained following three sprays compared to 5 088 kg/ha and 5593 kg/ha in 2002 and 2003, respectively, recorded for the control. Bentex Tor Benlate 50 WP could be used to reduce the effect of cercospora leaf spot and improve groundnut production in the sudan savanna of Nigeria.

Septoria melissae Desm., the most important pathogen of lemon balm (Melissa officinalis) occurs each year on plantations. The fungus may cause serious yield losses in the absence of proper plant protection. Breeding resistant or tolerant cultivars could play an important role in plant protection of medicinal plants. However, only a few descriptions of tolerant varieties of lemon balm are available. The goal of this work was to evaluate the susceptibility of three accessions of M. officinalis against the pathogen of Septoria leaf spot under field conditions at Budapest-Soroksár (Hungary) in 2017–2018. Differences in susceptibility of the accessions were observed in both years. The accession of M. officinalis subsp. altissima proved to be the least susceptible to Septoria infection. The frequency of the infected leaves was only 5.1 and 28.1% in 2017 and 2018, respectively. However, the cultivar M. officinalis subsp. officinalis ‘Lorelei’ turned out to be the most susceptible to the pathogen with an average infection level of 26.1 and 66.6%, 1.3–6.1 times higher than that of the other accessions in each year, respectively. Development of disease tolerant M. officinalis cultivars may be an effective tool in the plant protection of lemon balm.

Several species of Solanum produce secondary metabolites with antimicrobial activity. In

the present study, the inhibitory activity of Solanum chrysotrichum, S. erianthum, S. torvum

and S. rostratum against phytopathogenic Curvularia lunata was determined. Methanol extracts

from roots, stems, leaves and fruits were evaluated by the method of mycelial inhibition

on agar and the minimum inhibitory concentration (MIC) was determined on a liquid

medium. To increase the antimicrobial activity, the combined activity of the most active

extracts for each phytopathogen was also determined (a combination of intra and interspecies

extracts). The results showed that 12 of the 16 methanolic extracts of Solanum species

had antifungal effects against C. lunata. The extracts of S. rostratum and S. erianthum

developed the highest activity (~80% inhibition and 28.4 MIC μg . ml–1), even, equal to or

greater than, the reference fungicide. The mixture of the active extracts of S. chrysotrichum

and S. torvum increased their activity. Various extracts affected the macro and microscopic

morphology and most of them reduced the number of conidia of the fungus. This resulted

in the capacity to control the vegetative growth and reproduction of C. lunata, the causal

fungus of corn leaf spot disease.