نشریه آفات و بیماریهای گیاهی
سال نود و دوم شماره 1 (پیاپی 118، شهریور 1403)

Chickpea pod borer, Heliothis viriplaca, is an important pest of rain-fed chickpea (Cicer arietinum L.) fields in most regions of Iran. During 2017-2018, spatial distribution and fixed precision sequential sampling plans of, H. viriplaca population were investigated in rain-fed chickpea fields in Lorestan provinces. Regarding to the fitting of data with Taylor's power law and Iwao’s patchiness, parameters of these methods were used to develop of enumerative sequential sampling plans for each region. Results showed that, Taylor's b and Iwao’s β were significantly>1, indicating that H. viriplaca populations were aggregated in Lorestan provinces. Sample size curves were calculated and compared at 10%, 15% and 25% levels of precision. Validation results of Green's and Kuno’s models showed that, to achive a precision of 0.25, which is generally accepted in IPM programs, it is necessary to take samples with an average sample number (ASN) of 58 and 66 samples for green’s and kuno’s models, respectively.

Bacterial canker is a significant disease affecting stone fruit trees in cold regions. The incidence and severity of the disease can vary depending on factors such as rootstock, cultivar, orchard management, and other predisposing conditions. In this study, the response of commercial almond and peach cultivars in Chaharmahal va Bakhtiary province to Pseudomonas syringae pv. syringae (Pss) and Pseudomonas syringae pv. morsprunorum (Psm) was evaluated using both seedlings and detached branches. The results indicated a notable difference in disease severity (canker length) among cultivars and isolates of the two pathovars. All almond cultivars displayed varying degrees of susceptibility, with Shahroud 12 (Ferragnes), Pooya, Shahroud 7 (Ferraduel), Rabie, and Mamaee exhibiting the highest disease severity and bud death. Additionally, there was a significant variance in pathogenicity indexes (disease severity, bud death, and dieback) between the two pathovars, Pss and Psm. Peach cultivars also exhibited distinct reactions to the bacteria. The local cultivar Zaafarani was the most sensitive, while Kardi was identified as a tolerant cultivar. GH Hill and Elberta were considered sensitive cultivars as well. Overall, none of the almond and peach cultivars studied in this research demonstrated resistance to the bacterial canker pathogens.

The experiment was conducted with the aim of investigating the characteristics of germination and growth of seeds and seedlings of starthistle under the influence of various concentrations of rosemary and Shirazi thyme essential oil. In the study of seedling growth characteristics, the factors considered were: A) Type of essential oil and B) Essential oil concentration (5, 10, and 20 µl/ml). The control treatments consisted of distilled water, distilled water + Tween 20, and herbicide. Rosemary at 0.5-20 µl/ml reduced plumule length by 32.33-100% and radicle length by 62.62-100%. Shirazi thyme at the same concentrations led to 83.67-100% reductions in plumule length and 83.49-100% reductions in radicle length. The reducing effect of Shirazi thyme essential oil on seedling shoot length and dry weight at concentrations of 20 and 10 µl/ml compared to rosemary was almost 2.2 and 2.7 times, respectively. Shirazi thyme exhibited a greater inhibitory effect on seedling root length and dry weight, compared to rosemary. Furthermore, with increasing concentrations of essential oil, particularly in the case of Shirazi thyme, electrolyte leakage increased and photosynthetic performance index decreased.

The Silver Y, Autographa gamma and the Turnip moth, Agrotis segetum are considered amongst the most important agricultural pests in the world and Iran. In this paper, the potential distribution of these species in Iran and the important climatic factors affecting their distribution were determined using MaxEnt model, R package and ArcGIS based on their occurrence data. The results showed that, the most suitable areas in both species, are restricted to the northern Provinces; but in A. segetum the Bushehr Province, parts of the Chaharmahal and Bakhtiari and Kohgiluyeh, and Boyerahmad Provinces, and the north of Fars are also suitable. The main environmental variables contributing to their distribution were isothermality (bio2/bio7) (bio3), average wind speed in August (wind8), and precipitation seasonality (coefficient of variation). Moreover, precipitation of the driest quarter (bio17) and precipitation of the wettest quarter (bio16) were dominant climatic factors in Au. gamma and A. segetum, respectively. Additionally, the altitude had a major effect in distribution model of A. segetum. Having knowledge about the suitable areas for these species considering their host preferences will be effective in providing their management programs.

Despite the use of robust statistical methods and fuzzy-neural networks, models that predict the distribution of organisms have seen rapid development in the field of ecology. However, due to the challenges associated with sampling, these studies often lack sufficient samples. In this research, we compared geostatistics and fuzzy-neural networks to estimate the distribution of the tomato fruit worm in a tomato farm in Kermanshah city. For this purpose, the length and width coordinates of the sampling points at the field level were identified and used as inputs for both methods. The output of each method was the count of this pest at those locations. In the geostatistics approach, we employed the normal Kriging method, while in the fuzzy-artificial neural network approach, we used the sigmoid activation function. A comparison of the results from geostatistics and the fuzzy-neural network demonstrated the superior performance of the fuzzy-neural network. The coefficient of determination for the fuzzy-neural network and geostatistics was 0.9 and 0.6, respectively. In conclusion, the fuzzy-neural network method, by integrating latitude and longitude factors, was able to predict the density of the tomato fruit worm with high accuracy.

To determine the density of overwintering larvae (OL) and the algorithm of striped stem borer (SSB) population changes in single/double cropping under traditional and mechanized methods, several traits including the number of alive (AL) and dead larvae in the center and margin of the field were assessed at six periods. The number of egg mass (EMN) was also measured in the nurseries of single/double cropping systems. Results indicated that AL in the 1st sampling (2.5) was higher than the last one (0.9) in the center part of the field than the margin (P<0.01). In double cropping of rice, AL decreased in the center of the field while in the margin of the field highly increased. In nurseries, EMN was higher (2.35) in the double cropping compared with that in the single cropping (0.75) (P<0.01). We also found that EMN in traditional nursey (1.9) was higher than that in the mechanized one (1.21) (P<0.01). Hence, the last sampling time demonstrated that larvae pereferred highly the rice plants grown at the margins of the field. Accordingly, there was a declining trend for the transitional larvae population at field as well as a drastically declining trend at the nursery in both cropping systems. Therefore, the two mentioned cropping systems of rice won’t affect the population of OL at the next season rice crop.

Citrus psylla (Diaphorina citri) is one of the most important citrus pests in the world. In the first part, the experiment was carried out with five treatments including thiacloprid (OD24%), spirotetramat (SC10%), imidacloprid (SC 35%) and control in four replications. In the second part, the effect of the mentioned insecticides on the mortality of adult and pupa and parasitism rate of Tamarixia radiata was investigated. The results showed, in three days after spraying, imidacloprid (0.75 and 1 ml/L) had the greatest effect on Asian citrus psyllid (71.56 and 69.4%). The toxicity of imidacloprid on parasitoid adults was more than 80% which it was placed in the third group moderated harm. Thiacloprid and spirotetramat had less than 70% toxicity and were placed in the second group slightly harm. The Emergence percentage of adults from pupa exposed to spirotetramat was more than 90% and thiacloprid about 80%. The highest parasitism percentage of parasitoid was occurred in control (90.1%) and then in spirotetramat (0.5 and 0.75 ml/L) 85.4 and 81.9% respectively.

White button mushroom (Agaricus bisporus) has a special place in the food basket worldwide because of its high nutritional value and medicinal properties. To identify bacterial species associated with brown spot disease of edible mushrooms symptomatic samples were collected from Alborz province farms. Moreover, healthy mushrooms were sampled to isolate biocontrol bacterial agents. Sixty-one bacterial isolates were isolated from symptomatic samples among which 19 isolates induced wide, watery and sunken spots on the surface of the cap and necrosis of the middle part and the base of edible mushroom. Nine non-pathogenic isolates were isolated from healthy mushrooms among which four isolated were selected for auxin hormone, siderophore and production of phytase, protease, lipase, lecithinase, cellulase and chitinase enzymes production assays. Biochemical and molecular tests were performed to identify pathogenic and endofungal bacteria. Based on the 16S rDNA sequence analysis isolates were classified into the pathogenic genera including Pseudomonas, Chryseobacterium, Ewingella, Brucella and Klebsiella and endofungal species including Bacillus velezensis, Kocuria rhizophila, Bacillus wiedmannii.

In two metal structure cucumber greenhouses (each unit ~1300 m2) in Varamin region, an IPM program based on biological control (treatment) was compared with the conventional pest control method (control) during winter-spring cultivation season (2021-2022). In the treatment greenhouse, pests were controlled by augmenting hunter fly, Coenosia attenuata, population and releasing indoor produced biological control agents of three predatory mite species, Neoseiulus californicus, Phytoseiulus persimilis, and Amblyseius swirskii. Moreover, air-borne and soil-borne diseases were managed with chemicals and bio-fungicides, respectively. Pest monitoring of two greenhouses was done every other week by three methods including a) observational survey and flaging the attacked plants, b) random sampling of 15 plants, and c) recording the number of pests on the sticky card traps. Percentage of plants infested with thrips was high in both treatment (62%) and control (31%) greenhouses. Leaf miners and whiteflies infestations were observed, but well controlled by predatory fly, C. attenuata, in both greenhouses. Predatory mites also stopped the development of spider mite population in the treatment greenhouse. Biological agents had an acceptable control on pests at average daily temperature up to 25°C and humidity of at least 50-60% and therefore, they can be a suitable alternative to conventional chemical control.

Rice striped stem bore has been considered as a dangerous pest in the country's rice fields for nearly fifty years. This research was conducted to determine the effective daily temperature, the effect of environmental factors on the biology of the pest and the number of pest generations. The results of this study showed that the average total effective temperature for the rice striper over four years was about 822 degree-days. The average of the total temperatures required for the life stages of the rice stem borer to separate the eggs, larvae, pupae and adult insects were in the range of 70, 551, 104 and 92 degree days respectively. Also if the adult insect receives a temperature of more than 90 degree-days, it has the ability to enter the egg stage. One of the most important climatic elements in the life of the striped stem borer pest for adult insects was the temperature between 22 and 32 degrees Celsius and sunny hours, relative humidity and temperature for egg clusters, for larvae, temperature and relative humidity related to the stem. The investigations of this research showed that the rice stem borer pest completes its life cycle in the second generation, similar to the first generation, by receiving the total temperatures of more than 823 days and is transferred to the third generation. According to the resuls of this study, the striped stem borer pest has two and half generations in Guilan conditions.

Cupressus sempervirens L. var. horizontalis is one of the indigenous species of Iran, the natural habitats of which are regarded as significant forest reserves within Iran. In the northern of Iran, cypress trees have commonly been observed in both natural and artificially planted forests. The purpose of this study was to investigate the fungal factors affecting the common cypress tree die back in Hassanabad (Mazandaran province) during the summer of 2023. Study of the affected trees indicated drying in the terminal branches of the trees, blight and necrosis of the upper branches, as well as canker formation on the trunks of common cypress trees. The infected tissues of common cypress trees were cultured on potato dextrose agar medium. Fungal isolates were obtained. Based on the macroscopic and microscopic characters of the isolates they were identified as Diplodia cupressi in the laboratory. To confirm the morphological identification the rDNA sequence data (ITS1-5.8S-ITS2) were obtained using primers ITS1 and ITS4, and nBLAST. The pathogenicity of the fungus was approved on potted cypress seedlings. This study represents the major role of D. cupressi as the causal agent of Common cypress canker in North of Iran. It seems that the climate change and drought conditions provided the favorable environment to outbreak of the disease

Sophora mollis (Royle) Backer, Anagyris foetida L. and Spartium junceum L. (Fabaceae), have serve dual roles as medicinal and ornamental shrubs. The first two species are deeply rooted in Iran's natural heritage, while the latter is a rare botanical find, as highlighted by Hosseinzadeh et al. (2015). Recent observations at the Kashan Botanical Garden have brought to light a significant ecological disturbance: the infestation of Uresiphita gilvata (Fabricius, 1794) larvae. Documented for the first time in October 1402 and subsequently in the spring of 1403.