Evaluation of Trichoderma harzianum for controlling root rot caused by Phytophthora capsici in pepper plants

The ability of Trichoderma harzianum to control the rotting of pepper ( Capsicum annuum ) plant roots caused by Phytophthora capsici was studied. Interactions between the fungi were assessed in vitro on three culture media (V8c, Czapek and 2% water agar) and in vivo in plants grown in a substrate inoculated with P. capsici and T. harzianum . Studies on mutual antagonism in vitro showed that P. capsici was inhibited by T. harzianum ; however, the intensity of inhibition differed according to the medium used, being greatest on Czapek. Analysis of the fungal populations in the plant growth substrate showed that T. harzianum consistently reduced that of P. capsici over time. This reduction in the pathogen population was associated with a reduction in root rot of between 24 and 76%, although plant growth (dry weight) was still reduced by 21.2–24.7%, compared with the uninoculated control. In the absence of T. harzianum with the same pathogen inoculum levels, the reduction in dry weight was 59.8–68.6%, suggesting that T. harzianum reduced the damage.     

Effect of soil type and soil water content levels on pupal mortality of the peach fruit fly [Bactrocera zonata (Saunders)] (Diptera: Tephritidae)

Peach fruit fly (PFF), Bactrocera zonata, is one of the most dangerous pests of horticultural crops worldwide. This pest spends part of its life cycle in the soil as pre-pupae and pupae. Therefore, the effects of soil type and soil water content levels (SWCLs) on pupal mortality rates of the PFF were studied in an attempt to use soil moisture as an abiotic management strategy for this pest. The effect of clay, loamy, and sandy soils with SWCL of 0, 10, 25, 50, 75, 90, and 100% of field capacity on three ages of PFF pupae (newly formed, 4- and 7-day-old pupae) were studied. Results demonstrated significant effects of SWCLs on pupal mortality rates of PFF. SWCL was the factor with the most remarkable effect (48.47%), meanwhile soil type had a feeble effect (0.65%). Newly formed pupae were more susceptible to SWCL levels than 7- and 4-day-old pupae. Results suggest that sustaining SWCL near 100% of field capacity significantly (p?=?0.000) suppressed PFF population; therefore it could be an important component of Integrated Pest Management against this insect species.     

Production and Germination of Oospores of Phytophthora infestans (Mont.) de Bary in Morocco

One hundred and eight isolates of Phytophthora infestans were collected from infected potato and tomato crops in the middle-north of Morocco during 1997–2000. Pairings of these isolates with tester isolates of mating type A1 and A2 revealed that 60% of the isolates were mating type A2 (65/108) and 40% were mating type A1. After 10 days incubation at 20 °C and a 16-h photoperiod, approximately 25% and 18% of the oospores produced in-vitro germinated in potato soil extract and potato root extract, respectively. Oospores were observed in potato leaf tissues in pairings that were fertile in-vitro. Maximum production of oospores was obtained in potato leaves of cultivars that were moderately susceptible (Desirée, Nicola) after 10 days of incubation at 15 °C and a 16-h photoperiod. These results confirm the presence of P. infestans strains that are sexually compatible under Moroccan climatic conditions. Production of oospores constitutes a threat for these crops because of the occurrence of recombinants with new virulences which may be difficult to control and as a consequence survival of oospores in absence of the host plant in the soil.     

Screening study for potential lead compounds for natural product-based fungicides: I. Synthesis and in vitro evaluation of coumarins against Botrytis cinerea

An efficient, one-pot synthesis of angular and linear dihydropyranocoumarins, along with C-6 and C-8 prenylated coumarins is reported. These compounds, together with single- and furanocoumarins, were tested for their potential antifungal activity against the phytopathogen Botrytis cinerea Pers ex Fr. The results show that furanocoumarins may be able to control the fungus B cinerea.     

Zinc and Boron Application at Different Phenological Stages Alleviates Tree Growth,Fruit Yield and Quality of Sweet Orange Cv. ‘Blood Red’

The deficiency of micronutrients, particularly zinc (Zn) and boron (B) has affected vegetative growth, yield and fruit quality of sweet orange in many citrus growing areas of Pakistan. The present study was conducted in 2015 and 2016 to determine the impact of Zn and B supplementation on growth and quality of sweet orange cv. ‘Blood red’. Pre-harvest foliar application of variant Zn and B levels was done at different phenological stages of fruit growth and development, i.e., full bloom, fruit set and premature stage. Results have concluded that pre-harvest foliar application of Zn and B augmented phosphorous, Zn, B, potassium, iron, and manganese contents in leaves, particularly Zn and B content from deficient to optimal level. Moreover, the combined application of Zn and B has also significantly enhanced vegetative characters such as tree height and spread along with reproductive characters, i.e., incremented numbers of fruit, fruit weight, total soluble solids, titratable acidity and ascorbic acid contents. However, among stage comparison, outcomes depicted that foliar application of Zn and B at full bloom?+?fruit set?+?premature stage resulted in maximum production with high quality fruits.

     

Current titles in soil science

Nine extraction procedures were tried on four calcareous soils containing very low to extremely high amounts of calcium carbonate. Correlation studies relating chemically extractable zinc to both concentration in and uptake of zinc by young sorghum and maize plants grown in the greenhouse indicated that five extraction methods exhibited a high degree of correlation. When the methods were compared among themselves, the highest correlation was obtained for dithizone and EDTA-ammonium-carbonate methods. The EDTA-ammonium-carbonate method seemed to reflect the available zinc status of the soils more accurately than other methods.     

Improvement of the composition of Tunisian myrtle berries (Myrtus communis L.) alcohol extracts

Different extracts from myrtle berries were obtained using alcohol-water mixtures as an extraction medium in the range of 60-90% (v/v) to study the extraction efficiency in the preparation of myrtle liqueur. Flavonoids and anthocyanins were identified by high-performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry and quantified during the maceration period by HPLC coupled with ultraviolet/visible detection. The antioxidant activity was tested by the 2,2-diphenyl-1-picrylhydrazyl assay. Dry matter, pH, and color parameters (L, a, b) were also analyzed. At the end of the maceration period, EE80 showed better anthocyanins stability and the highest total antioxidant activity (87.5%). These results suggest that the use of ethanol 80% provides the extract with the best characteristics for liqueur preparation. The present study contributes significantly to increase the marketing appeal of myrtle berries.     

Interactive effect of salinity and silver nanoparticles on photosynthetic and biochemical parameters of wheat

The present study investigated the influence of seed priming with silver nanoparticles (Ag NPs), 0, 2, 5 and 10 mM, on growth and biochemical parameters of wheat (Triticum aestivum L.) under salt stress. As expected, 150 mM of NaCl decreased the shoot fresh and dry weights and chlorophyll contents and increased the catalase (CAT) and peroxidase (POD) activities. Salinity enhanced the concentration of proline, soluble sugars, malondialdehyde and hydrogen peroxide. Seed priming with Ag NPs increased the shoot fresh and dry weight of normal and salt-stressed plants. Lower concentration of Ag NPs decreased the total soluble sugars and proline contents, while the higher Ag NPs levels increased these contents compared to the control. The combined application of Ag NPs and salt stress increased the soluble sugars and proline contents, while it decreased CAT activity and increased POD activity compared to the respective Ag NPs treatments alone. Overall, our results demonstrated that Ag NPs enhanced the salt tolerance in wheat, but the long-term response of Ag NPs under salt stress needs further investigation.