نشریه مهار زیستی در گیاه پزشکی
سال دهم شماره 2 (پاییز و زمستان 1401)

The increasing human population, excessive exploitation of natural resources and significant industrial growth of countries in a short period of time have caused fundamental and irreversible changes in the biology-biochemical cycles of the natural ecosystems of the planet and widespread pollution of the environment, water, soil and air around us. These factors eventually lead to the occurrence of unnatural events such as climate changes and the risk of extinction of many plant, animal and micro-organism species.  Although the use of new technologies has led to the industrial, agricultural and economic development of human societies, but it has resulted in many negative environmental effects. The release of various environmental and air pollutants in the environment, such as pesticides, herbicides, nitrogen and sulfur oxides, heavy metals, etc., not only threatens human health but also seriously endangers the health of other living organisms. For several decades, has become common the use of living organisms as bioindicators to obtain information about the amount and type of environmental pollutants. Using bioindicators, it is possible to track the early signs of environmental and atmospheric pollution and the variety of pollutants. Various organisms are used as bioindicators for biological monitoring and tracking (biomonitoring) of air pollution, among these organisms are lichens. Lichens are one of the most important "biological indicators" for monitoring air quality, measuring the accumulation of heavy metals in the environment, measuring the health of forests, examining the extent of damage to the ozone layer, and obtaining information on pollutants and the variety of pollution at the local and regional level..

The egg parasitoid Trichogramma spp is biological control agents of a wide range of agricultural and forests pests. At least 12 species of Trichogramma are commercially used in biological control programs in different countries of the world. These wasps can be reared on secondary hosts more quickly and easily than other biological control agents. So far, 11 species of Trichogramma have been identified from different parts of Iran and some species have reached mass rearing in the country. During the last few decades, different species of Trichogramma have been used in biological control of many pests including carob moth in pomegranate, rice stem borer, codling moth, European corn stem borer and cotton bollworm in different parts of Iran. Chemical control is currently the most important tool in agricultural pest management, the use of hazardous chemical compounds has caused environmental pollution, secondary pest outbreaks, emergence of resistance, threats to human health and adverse effects on non–target organisms. Most conventional pesticides used to control pests are broad–spectrum compounds that kill natural enemy populations similar to the pests. Numerous studies have shown that pesticides used to control pests have many side effects on natural enemies, including changes in growth, development rate, and sex ratio. To evaluate the side effects of pesticides on various biological agents, some standards have been developed by the IOBC. The results of which, in addition to international acceptance, can provide valuable recommendations for use in IPM programs and help to find selected compounds compatible with biological control agents and reduces the use of pesticides. The present article is a review of studies on the side effects of pesticides on different species of Trichogramma wasps in Iran, which is being conducted for the first time and hoped to pave the way for the development of integrated pest control in the country..

Rhizoctonia root rot is a widespread and destructive disease that affects sugar beet yield in Iran and worldwide. In this study, we investigated integrated disease management methods, including the use of resistant cultivars and fungicides, to prevent the development of the disease. The present study focused on the Shokoufa susceptible cultivar and the Novodoro resistant cultivar, and tested three fungicides of Celeste, Uniform, and Maxim. The experiment was conducted under natural and artificial contamination conditions during 2022. The results showed that the Uniform fungicide effectively prevented the development of the disease on the resistant cultivar, resulting in a harvest index of 70.59%. Although this fungicide did not work as effectively on the susceptible cultivar, it still showed better performance compared to other experimental treatments. The Celeste fungicide had a disease index of 3.29 on the resistant cultivar, with 5% of the root surface having ulcers. However, it did not have a significant effect on disease control in the susceptible cultivar, which showed a sensitivity reaction. The harvest index of the resistant cultivar in this treatment was 76.47%, while the susceptible cultivar had a harvest index of 11.76%. The Maxim fungicide and control treatments had similar effects on both the resistant and susceptible cultivars in terms of disease and harvest indexes. Although the severity of the disease was lower in the resistant cultivar compared to the susceptible cultivar, both cultivars showed a low harvest index and were in the sensitive range..

The predator mite, Amblyseius swirskii Athias and Henrioti, is one of the effective and polyphagous biological control agents that feed on different pest species such as thrips, whiteflies, and two spotted spider mites. Currently, it is used to control western flower thrips (WFT), Frankliniella occidentalis (Pergande), and some other insect pests but in times of outbreak and high density of the pest population, its efficiency is reduced and it is necessary to use complementary methods to control the pest damage. In this study, the effect of treated bell peppers (Lorca variety) with Jasmonic acid (0.5 mm), Trichoderma harzianum Rifai T22 (10 ml per plant from 107 spore/ml suspension), and the combination of Jasmonic acid with T. harzianum (JA + Th) was investigated on the biological characteristics and life table parameters of A. swirskii reared on WFT the. The experiment was carried out with 80 replications for each treatment in constant environmental conditions (25 ± 1°C, 65 ± 5% RH, and 16:8 h light: dark). Based on the results, the longest (9.41 days) and shortest (7.94 days) developmental time of immature stages were obtained in JA + Th treatment and control, respectively. The shortest female adult longevity (24.92 days) were also observed in JA + Th treatment. All the life table parameters showed a significant difference. The highest and lowest values of the intrinsic rate of increase (r), net reproductive rate (R0) and, finite rate of increase (λ) were estimated as 0.1688 and 0.1300 day–1, 24.49 and 11.71 (eggs/individual), and 1.184 and 1.139 day–1 for control and JA + Th treatment, respectively. The results of this study could be used in the application of A. swirskii with JA + Th treatment in integrated management programs of WFT..

Vitex agnus–castus, belonging to the Lamiaceae family, is used in traditional medicine in Iran. With the aim of finding natural compounds with anti–fungal and eco–friendly properties, the effect of Vitex agnus–castus essential oil on mycelial growth of three plant pathogenic fungi was evaluated. The study was conducted as factorial experiments with three fungal isolates, including Botrytis cinerea, Penicillium digitatum and Aspergillus flavus. The inhibitory activity of six doses of the essential oil (2, 4, 8, 16, 32 and 64 μl) with three replicates were examined. Also, the antioxidant effect of the oil was evaluated by DPPH free radical inhibition method. The chemical compounds of the oil were identified and quantified using GC–MS method. Analysis of the chemical composition of the essential oil showed that α–pinene (52.70%), limonene (15.77%) and (E)–caryophyllene (8.69%) constitute the most components of the essential oil, respectively. As results of the study showed that the 64 ml of V. agnus–castus essential oil has the greatest inhibitory effect on mycelial growth of studied fungi. Among the studied fungal species, P. digitatum showed the least and B. cinerea showed the most sensitivity to the of V. agnus–castus essential oil. Also, the essential oil was showed a high antioxidant activity with IC50 value of 0.07 mg/ml compared to the BHT (IC50 = 0.04 mg/mL), as a synthetic antioxidant..

Application of chemical fungicides is the primary method of tomato early blight disease management in Iran. In this study, the efficacy of CangMei biofungicide in doses of 0.75, 1 and 1.25 ml L–1 were assessed on the control of this disease alongside with Iminoctadine Tris and control without the use of fungicide. The experiment was carried out in Fars and Khorasan Razavi provinces according complete randomized blocks with five treatments and four replicates. The first spraying was performed after flowering stage, the second one was after the first symptoms of the disease was observed and repeated every 7 days up to 5 times. The effects of pesticides were assessed six times on the development of the disease on the leaves based on disease severity and the data was analyzed using SAS software. The results showed the best treatment to control of tomato early blight disease was Belkute®. Cang Mei bio fungicide in dose of 1.25 ml L–1 had the greatest effect among examined doses and reduced Area under disease progress curve (AUPDC) 30.16% and 33.21% in Fars and Khorasan Razavi respectively. Due to the destructive effects of chemical fungicides, Cang Mei could be recommended in dose of 1.25 ml L–1 to produce healthy crop..

Alfalfa stem nematode (Ditylenchus dipsaci) is one of the most important and destructive pests of economic crops such as alfalfa, garlic, onion and tulip. The effects of Saponins from the aerial parts of six alfalfa ecotypes on the mortality of alfalfa stem nematode was investigated under laboratory conditions. In this study. The results showed that among the crude Saponin treatments, the amount of 90 microliters from the Hamedani and Faiz ecotypes had the highest effect with 96% and the amount of 50 microliters from the local Miandoab ecotype 42% had the least effect on the nematode mortality. Also, among the pure Saponins, the amount of 50 microliters of Hamedani, Shiraz–Plycross and Faiz ecotypes with 99%, and the amount of 10 microliters of Nishaburi ecotype with 68% had the highest and lowest effect, respectively, on the mortality of the nematode. In most ecotypes, increasing the concentrations of crude Saponin from 50 to 90 microliters and pure Saponin from 10 to 50 microliters causing 54% and 31% mortalities led to an increase in nematode mortality. It means there is a positive correlation between alfalfa stem nematode mortality and the raw and pure Saponin concentration of alfalfa ecotypes. Subsequently, Hamedani, Faiz and Polycross Shiraz ecotypes showed the highest effect and Miandoab and Nishaburi local ecotypes showed the least effect on the mortality of this nematode. .

In this research, the compatibility of Trichoderma species along with Nanocide and fungicide for the integrated management of this pathogenic fungi Sclerotinia sclerotiorum, has been studied. For this purpose, the effect of three isolates of Trichoderma harzianum, one isolate of T. virens, one isolate of T. atroviride and one isolate of T. koningii on the three isolates of pathogenic agent (SS1, SS2, SS3) in PDA medium containing 5 levels of Nanocide (0,30,60,100,130) by dual culture technique in the laboratory condition were studied. Then the effects of T. harzianum (1211), T koningii (iso2) and T. virens (6011) with two levels of Noniocid (10 & 30 ppm) and Iprodione+carbendazim fungicide (2 & 5 ppm) on one isolate of pathogenic agent in greenhouse condition, were evaluated. The lowest inhibition of mycelia growth of S. sclerotiorum in PDA medium with Nanocide, was 6%, that indicated for treatment S. sclerotiorum (SS2) × T. virens (6011) at level 10 ppm. In greenhouse condition, Trichoderma spp were tested in two stages, seed coated with Trichoderma conidia cell suspension and use Trichoderma mixed with soil. The evaluated parameters were height and wet and dry weight of the plant. The first experiment, was seed coated with Trichoderma conidia cell suspension, the most fresh weight was for T. harzianum (1211) as control and the most height was for T. koningii (iso2) alone. The second experiment, was for Trichoderma mixed with soil showed a significant increase in the most fresh and dry weight were for T. harzianum (1211) + 30 ppm Nanocide treatment and the most height of seedlings was also for T. harzianum (1211) + 2 ppm Iprodione–carbendazim (P≤0.01(. the statistical grouping showed that the treatments in which Trichoderma species were used alone showed no significant difference with treatments with Nanocid and fungicide in the wet and dry weight and height plant. Beside, using Trichoderma alone rather than the combination of Nanocid and fungicide, showed the better effect on growth parameters of the infected canola.

The use of biocontrol agents is a promising and safe method towards achieving environmental goals for controlling plant diseases. However, due to the lack of stability and appropriate and applicable formulations, the results obtained from the application of these agents, especially in agricultural fields, have not been sufficiently efficient. This study was conducted with the aim of developing a capsule formulation using sodium alginate to increase the viability and improve the performance of Bacillus subtilis. Capsules were prepared using the ionic gelation method. The encapsulation efficiency was estimated to be 99%. The mean size of the wet and dry capsules produced was 2600 and 1000 micrometers, respectively. The effects of ultraviolet radiation on the survival of B. subtilis showed that the bacterium in the capsule state (wet and dry) was more resistant to ultraviolet radiation compared to the non–encapsulated state. With increasing exposure time to ultraviolet light, bacterial cells resistance in the capsule state were greater than in the non–encapsulated state. The results of the thermal resistance examination at different temperatures emphasized the positive role of the capsules in increasing the survival and resistance of B. subtilis compared to the non–encapsulated state. The survival percentage of non–encapsulated B. subtilis after 60 days at 25 and 35 degrees Celsius decreased by 42% and 47%, respectively. However, for the encapsulated B. subtilis, the survival percentage decrease after the same period and temperature was estimated to be 16.5% and 26%, respectively. Greenhouse results showed that the use of B. subtilis capsule formulation reduced disease percentage compared to non–encapsulated B. subtilis and sodium alginate capsules alone. The disease percentage in plants treated with encapsulated B. subtilis was estimated to be 4.44%, while this rate was 73.33% in the control. Plants treated with encapsulated B. subtilis had significant differences in growth indices compared to the control. Growth index changes in relation to different formulations of B. subtilis (encapsulated, non–encapsulated) and sodium alginate capsules alone were significant only for root height. These results emphasize the positive role of using B. subtilis and capsule formulation in controlling damping–off caused by Rhizoctonia solani in tomato plants.

Adalia and Oenopia conglobata are two polymorphic species of ladybeetles. They are active in all of ecosystems and play important role in control of Aphids. To study the polymorphism of these species, weekly sampling was done in spring and summer in 1400 in Sarakhs region. The specimens were transferred to the laboratory and both species were identified based on their appearance, male reproductive organs and with the help of valid keys. Then, morphs of Adalia and O. conglobata were separated, identified and frequencies of each morph were determined on host plants and host insect too. A total of eight casts were collected for the Adalia ladybug and five casts were collected for the O. conglobata. The highest frequency related to forms five and six for A. bipunctata and forms three and four for O. conglobata. This study was conducted for the first time in the region and can be the introduction of additional research to identify the forms of other species of Coccinellidae family.

The root–knot nematode (Meloidogyne incognita) on tomato (Solanum lycopersicum Linn.) is one of the most important plant pathogens, causing economic damage worldwide and in Iran. In order to biologically control this nematode, after nematode multiplication on the susceptible tomato variety (Early Orbana Y) and obtaining a pure and abundant nematode population, the plants were irrigated with a solution of 3 per thousand Probi 96 (containing Bacillus subtilis) and Chitoplus (containing chitosan). After 45 days of applying the treatments, the seedlings were transferred from the greenhouse to the laboratory, and growth indices such as fresh and dry shoot weight, shoot length, fresh and dry root weight, root length. Also, disease indices such as the average number of galls, the number of nematode egg masses in the root, the number of nematode eggs in the root, the number of second–stage juveniles in the soil, and the gall index were measured. The results showed that the use of B. subtilis and chitosan, either alone or in combination, led to an increase in plant growth indices and a reduction in nematode pathogenicity indices. Therefore, based on the results obtained in this study, it can be concluded that the use of these compounds is suggested as one of the effective strategies in an integrated management program for root–knot nematodes in tomatoes.

Contaminated soil can be remediated by employing various types of microbes, such as bacteria, which have the ability to enhance plant growth and combat pathogenic microorganisms. Biological control is an environmentally adaptable method that utilizes living microorganisms like bacteria, fungi, and viruses to suppress plant pathogens through mechanisms such as competition, parasitism, antibiosis, and induced resistance. This study aims to assess the effectiveness of bioremediation bacteria as biological control agents against fungal pathogens affecting sugarcane. To achieve this objective, previously identified bacterial strains with potential in bioremediation of Atrazine and Metribuzin herbicides, including Brucella sp. (66A, 44A, and 65A), Pseudomonas putida 10A, Ensifer adhaerens 20m, Pseudomonas aeruginosa 15A, and Stenotrophomonas sp. 22A, were evaluated for their ability to inhibit the growth of Thielaviopsis ethacetica, Cytospora sacchari, Fusarium proliferatum, Bipolaris drechslera, Curvularia sp., Alternaria sp., and Nigrospora sp. The experiments were conducted using the dual culture method in a completely randomized design with three replications under laboratory conditions. The diameter of the bacterial inhibition zone and the percentage of fungal growth inhibition were calculated. The results indicated that P. aeruginosa 15A exhibited the highest growth inhibition against T. ethacetica, Curvularia sp., and Alternaria sp. On the other hand, Stenotrophomonas sp. 22A significantly inhibited C. sacchari, while both Stenotrophomonas sp. 22A and Brucella sp. 65A showed considerable inhibition against F. proliferatum. Bipolaris drechslera was most effectively inhibited by Brucella sp. 66A and Brucella sp. 44A, while P. aeruginosa 15A and Brucella sp. 66A exhibited prominent inhibition against Nigrospora sp. Notably, P. putida 10A did not display antagonistic properties against the tested fungi under laboratory conditions, whereas P. aeruginosa 15A significantly affected the growth of all examined fungi. Based on these findings, this study provides evidence that certain bioremediation isolates possess significant potential for biological control of specific fungal pathogens affecting sugarcane in laboratory conditions. Consequently, the antagonistic properties against important fungi in sugarcane can be utilized in agricultural activities. This strategy has the potential to decrease the reliance on fungicides in sugarcane farming, benefiting both the economy and the environment. Additionally, it can contribute to the maintenance and improvement of product quality and yield, while supporting sustainable cultivation..