green mold

The use of chemical pesticides has caused environmental hazards as well as the creation of residues on food products. In this research, the extracts of Zataria multifloraBoiss. and Garlic (Allium sativum L.) were used for controlling the green mold of orange caused by Penicillium digitatum, invitro and invivo at 15 ̊C. In this study, the effect of plant extracts against the pathogen was evaluated using two methods, included the paper disc and mixing with culture media. Then, the effect of these extracts on the fruit was studied against the pathogen. The level of activity of the enzymes including peroxidase, catalase and polyphenol oxidase, as well as total phenol content were measured. Finally, the expression of catalase, peroxidase and polyphenol oxidase genes was evaluated using the Real time PCR method. The results of disc test showed that aqueous and alcoholic extracts of garlic had the highest effect on fungal mycelium growth with 60 mg at ml concentration and 32.20 mm and 26.12 mm diameter of inhibition zone respectively. The mixing culture test showed that aqueous and alcoholic extracts of garlic with 65.25 and 75.26 percent of the inhibitory effect on the pathogen, respectively, showed the best control compared to the control in 600 mg at L concentration. The results of invivo assays indicated that 6×1000 concentration of aqueous and alcoholic garlic and thyme extracts had the lowest of decay area with 5.3 and 3.26 cm2 respectively (for garlic) and 7.44 and 4.15 cm2 for thyme. Results of enzyme activity of peroxidase and polyphenol oxidase showed that the highest activity of both enzymes was 9 days after sampling and in the treatment of 6×1000 garlic extract. Based on the results of laboratory and storage tests, the extract of both garlic and thyme are introduced as natural constituents with controlled potentials. The genes expression levels of enzymes as peroxidase, polyphenol oxidase, and phenylalanine ammonialis had the same trend to the activity of two enzymes over a period of 12 days. Based on the results of invivo and invitro tests, the extract of garlic and thyme are introduced as natural compounds with high controlling potentials.

Penicillium digitatum, the causal agent of citrus green mold, is one of the most important pathogens among citrus fruit rot agents. Unfortunately, the continuous application of chemical pesticides have serious effects on human health and environment. As well as development of resistance is a latest against their resistance to chemical pesticide. Today, research on bio-pesticides using microbial antagonists and natural plant products has become more important as viable alternatives to control postharvest diseases. In this research, some wide spread endemic plant spears were collected from North of Iran and their potential as natural bio-pesticide were evaluated. Metabolic extracts of these plants were tested on PDA medium in vitro and on citrus fruits in vivo for their efficacy to control P. digitatum when applied as disc diffusion method and soaking in plant extract suspension respectively. Results showed some plant extract produce inhibition zone around paper disc In vitro test, but in vivo test, only extract of Phytolacca americana has significant effect and inhibited spore production by Penicillium sp. Eleven Components were identified from Pytolea American extranets using eleven Chromatography by Hexane, Diethyl ether and Methanol solvents, an non-polar, semi-polar and polar solvent, respectively. And purified using thin layer Chromatography (TLC). The antifungal effects of each 11 components on P. digitatum showed only component were extracted with methanol polar solvent have the most antifungal properties.

In order to investigate the effect of different stages of sorting line on the development of orange post-harvest disease, two independent experiments were conducted. In the first experiment, fruit sampling was done upon arrival at the workshop (control) and after imposing each sorting line stage included washing with water immersion, washing with fungicide-containing hot water, waxing, sorting, as well as the elimination washing with hot water containing fungicides from the last two levels of the sorting stage (waxing, sorting). The fruit decay was assessed in three phases (7, 14 and 21 days after keeping the fruits at germinator). In the second experiment, the control fruit and final product of sorting (waxed oranges washed and unwashed with fungicide-containig hot water) were kept for 45 days in cold storage. The results showed that green mold, blue mold, and sour rot are the common diseases in the oranges. No significant difference was observed between the sorting treatments in the two modes of washed and unwashed with fungicide containing hot water. Further, more the percent of disease incidence and mean the disease severity increased over the time. Control treatments had 5.9, 33.3 and 33.3 percent of disease incidence in 7, 14 and 21 days evaluation steps, respectively. In the second experiment, the disease incidence was significantly lower in control compared to the other two treatments. In conclusion, it can be stated that sorting, as it is, increases post-harvest diseases and the rate of fruits decay cannot be reduced by using hot water containing fungicide and wax.