sonia seifi

Oak is a common and the most important species in Zagros forests of Iran. Zagros forests play a crucial and effective role in water supply, soil conservation and climate modification. Unfortunately, a significant part of those forests suffer from oak decline. Zagros forest covers almost 40% of Iran’s woodland which especially during the last two decades the population of oak trees (Quercus spp.) decreased mainly due to drought, diseases and insect pests. One of the most important pests in western oak forests is green oak leaf roller, Tortrix viridana L., (Lep.: Tortricidae) feed on oak leaves as the main host.  

This research aimed to assess and predict the degree of damage to the oak forests using remote sensing and GIS methods through regression analysis of the oak foliage remaining ratios of field plots with a vegetation indices of Sentinel-2 data during a year. Field monitoring carried on from April- 27-2020 to May-14-2020. For this purpose, in a two-kilometer-wide vector along the route from Sarovabad city to Bashmaq border, 100 sampling locations were randomly determined using GIS software. In each sampling location, four trees were selected in the four main geographical directions (in order to reduce the effect of directions on distribution of T. viridana population). Then, four branches (length about 100 cm) were randomly cut as a sampling unit, and the number of fifth instar larvae of T. viridana, were counted. The correlation between the number of T. viridana and elevation, slope, distance from the road, distance from the river, distance from residential areas, NDVI and solar radiation index were analyzed using Pearson's correlation test and multiple linear regression. Data normality was checked using the Kolmogorov-Smirnov statistical test. Data were analyzed using SPSS software (Version 26).

The results of Pearson's correlation analysis between the those variables and T. viridana population show the highest and lowest correlation of the T. viridana population with elevation (r= 0.651) and slope (r= -0.015), respectively. According to multiple linear regression, elevation had the highest correlation coefficient with T. viridana population density. In addition, solar radiation index, NDVI and distance from the river were ranked with strong to weak correlation, respectively. Results showed that, the relationship between slope and vegetation density is also significant (P= 0.032; r= 0.214). According to the distribution intensity map of the T. viridana, which was obtained using the multiple linear regression equation, it has been shown that the most distribution of the T. viridana was observed in the southwest of Sarovabad city. Clearly NDVI was convenient for separating different levels of damage.

It can be concluded that the population of T. viridana is obviously high at high altitude and in high tree densities. The results showed that the population density of T. viridana is higher wherever a dense vegetation was occurred. This research provided a feasible and quantitative method in the spatiotemporal prediction of green leaf roller occurrence by remote sensing and GIS. In conclusion, with the availability of population models, it is possible to limit the spread of T. viridana through earlier detection of pest incidence.

With the rising cost of chemical fertilizers and their negative impact on the environment, there is growing interest in the use of beneficial microorganisms to enhance soil and plant fertility. The present study showed that bacterial isolates can produce auxin and solubilized phosphate, which increases germination and plant growth indices under laboratory and greenhouse conditions. To investigate the effects of different nitrogen fertilizer rates on yield and nitrate accumulation in tomato plants, an experiment with eight bacterial treatments and three rates of zero, 300, and 900 kg urea per hectare was set up in a completely randomized factorial trial with three replicates in the greenhouse. Results showed that the growth-promoting bacteria significantly increased shoot dry weight and nitrate concentration in the absence of nitrogen fertilizer compared to the non-inoculated control. Evaluation of nitrate content in the plants showed that excessive fertilization with more than 300 kg of urea may lead to nitrate accumulation in the control plants. In all bacterial treatments, nitrate levels were lower than in the untreated control, even when three times the recommended amount of fertilizer was applied. In conclusion, plant probiotic isolates in integrated nitrogen fertilizer management systems can improve fertilizer efficiency and yield and reduce nitrate accumulation in plants

Bacillus velezensis is one of the plant probiotic bacteria that has been recently considered as one of the most powerful biocontrol agents. The purpose of this study is to introduce and investigate some of the characteristics of B. velezensis bacterium, which has been isolated from tomato rhizosphere in Kermanshah Province. In this study, B. velezensis increased shoot length, root length and dry weight of tomato plants by 78.86%, 56.68%, and 45.83%, respectively in comparison to uninoculated control; it also promoted seed germination percentage and seed vigor index under in vitro condition. Furthermore, some of the biocontrol properties of this strain such as the production of siderophore, HCN, and indole-3-acetic acid and solubilization of phosphate were evaluated. Biocontrol bioassay of this strain against Fusarium oxysporum f.sp. lycopersici under in vitro condition revealed that this strain can inhibit the mycelial growth in both dual culture and volatile compounds methods about 83% and 58%, respectively. The pot experiment results showed that B. velezensis caused a reduction in disease symptoms up to 87%. Finally, the whole genome sequence of this strain was identified using Illumina HiSeq2500 technology. Then genomic locations and coding sequences were identified in RAST database. In addition, the sequencing data were compared with existing sequences in the NCBI database. Results showed that this isolate has high similarity to (%100) B. velezensis. The genome of this isolate contains 4132868bp and 4329 CDs. The results suggest that B. velezensis has a good potential to be introduced as a plant probiotic bacterium.

Field bindweed (Convolvulus arvensis) is one of the most important weeds of fields and orchards over the world. Up to now lots of studies have been performed considering its biological control that insects have the highest share. We spotted a leaf-feeder beetle of C. arvensis, named Hypocassida subferruginea (Col.; Chrysomelidae), on farms, in Kurdistan province (Sanandaj, Kamyaran and Divandareh Counties). Adults and larvae feed on the leaves. According to our observations, the body length of male and female is 4.5and 5.3 mm respectively. In addition, this species has 5 larval stages with prepupal and pupal stages. The lengths of all larval instars, prepupa and pupa were calculated as follows: 1st instar: 1.5±0.1 mm, 2nd instar: 2.3±0.2 mm, 3rd instar: 3.0±0.5 mm, 4th instar: 4.2±0.1 mm, 5th instar: 5.1±0.1 mm, prepupa: 5.2±0.1 mm and pupa: 5.4±0.2. Moreover, the insect found to overwinter as adults in the soil and emerged in late April. Therefore, they have five generations per year. The results of host preference tests revealed that H. subferruginea feeds only field bindweed as compared to the other plants such as tomatoes, potatoes, chickpea or wheat.