JOURNAL OF CROP PROTECTION
Year:2020 | Volume:9 | Issue:3 |Papers Count:15

Three known species of the family Criconematidae namely Criconema crotaloides, C. princeps and Ogma zernovi were recovered from natural forests in Golestan province, and were characterized based upon their morphological and morphometric characters. The Iranian population of C. crotaloides was recovered from the rhizosphere of Fraxinus excelsior and is characterized by females 517-594 μ m long, having 64-70 not retrorse body annuli with smooth margin without lateral differentiation and RV = 11-14. The second species, C. princeps, was associated with Carpinus betulus and is characterized by females 421-506 μ m long, having 63-69 rounded to retrorse body annuli with smooth margin, marked by distinct lateral triangular arches and RV = 11-12. The main characteristics of this species and the status of some other previously reported populations as C. princeps were discussed. The last species, Ogma zernovi, was recovered from the rhizosphere of Quercus sp., and is characterized by females 350-653 μ m long, having 58-64 retrorse body annuli, each annulus with nine rows of short smooth scales in the middle of the body, the scales uni-or bi-lobulated, RV = 9-11, tail conoid and the last three annuli without projections. New observations on its morphology were added, comparisons were made with the type populations of the species and characteristics of the species were updated with including data of males and juveniles. Compared to the type populations, no remarkable differences were observed for the three studied species. All the three species represent new records for Iran.

Pseudomonas tolaasii Paine and Ewingella americana Grimont are considered as devastating pathogens in mushroom cultivation. Due to the short shelf life of button mushrooms, safe methods should be used to control these pathogens to avoid any toxic residues on the products. Plant secondary metabolites are assumed as important sources for biopesticides development. The aim of this study was to screen plant species for antibacterial properties against P. tolaasii and E. americana. Antibacterial activity of aqueous extract of 17 plant species on two pathogens was investigated in vitro using the disc diffusion method at 10 and 20 mg active ingredients per disc. Then the effect of extracts possessing antibacterial activity was tested on mycelial growth of button mushroom Agaricus bisporus (Lange) using the disc diffusion method. Analysis through measuring the diameter of growth inhibition zones revealed that the extract of Hymenocrater longiflorus Benth. and the other extracts including H. longiflorus, Achillea millefolium L., Eucalyptus sp. and Teucrium polium L. had significant antibacterial activity on E. americana and P. tolaasii, respectively. However, they had no inhibitory activity on mycelial growth of A. bisporus. The efficacy of four mentioned extracts was evaluated in the control of mushroom brown blotch disease caused by P. tolaasii, in vivo. Assessment of disease severity showed that all four extracts, at tested concentrations, had some level of preventive effect on P. tolaasii with no adverse effects on A. bisporus. It is noteworthy that the strength of the A. millefolium extract at 10% did not differ significantly from the 1% household bleach in reducing the disease severity. Therefore, it is possible that some plant extracts have the power to be considered as alternatives to chemical bleaches. Moreover, findings suggest that H. longiflorus extract is a promising candidate for control of P. tolaasii and E. americana in mushroom cultivation.

Brown spot, caused by Bipolaris oryzae, is a devastating disease of rice which can cause yield loss in most rice-growing regions of the world. Breeding for disease resistance is the preferred strategy of managing brown spot. Hence, identification and subsequent development of disease resistance in rice genotypes are crucial. The field resistance of 95 rice genotypes to brown spot was evaluated under water and fertilizer stress during 2017 and 2018. Partial resistance was assessed through reaction type (disease rating) and epidemiological parameters estimates i. e. final brown spot index, area under disease progress curve and apparent infection rate. Disease rating, brown spot index, and area under disease progress curve detected differences in the responses of rice genotypes to disease under field condition, which could be used to study brown spot resistance. Among the genotypes tested, 22 genotypes were resistant to moderately resistant (23. 16%) while majority were moderately susceptible to susceptible (76. 84%). A significant correlation between leaf angle and area under disease progress curve indicated positive influence of leaf erectness on severity of brown spot disease. Results showed that leaf infection did not significantly affect the number of filled grains per panicle or hundred seed weight, but caused yield decline by decreasing the number of productive tillers. Nevertheless, the infection of rice genotypes from flowering to ripening stages decreased the number of filled grains per panicle and grain weight. The resistant genotypes identified in this study can be exploited for future rice breeding programs to develop promising resistant lines in management of the brown spot disease.

Tomato bacterial wilt and canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm) is an economically important seed-borne disease in the major tomato growing regions all over the world. Also, this disease is present in northern, northwestern, and central provinces of Iran. This study aimed to isolate fluorescent pseudomonads with efficient antagonistic activity against Cmm from tomato rhizosphere and rhizoplane. In the present study, ninety six fluorescent pseudomonads were isolated from rhizosphere and rhizoplane of tomato plants using King’ s medium B agar and tested for antagonistic activity against Cmm by co-inoculation culture in vitro. Seed and roots of tomato transplants were inoculated with representative antagonistic strains and planted in the soil infected by Cmm in greenhouse. The incidence and severity of the disease were assessed on tomato as well as growth parameters. Nineteen strains exhibited inhibitory activity against Cmm in vitro and two selected strains (M1R1 and H1R1) were identified as Pseudomonas putida based on their phenotypic characteristics and partial 16S rRNA gene sequences. These two strains produced siderophore and hydrogen cyanide. In greenhouse, strain M1R1 reduced the disease incidence by 30% and 40% in Superluna and Falat cultivars, respectively. Strain H1R1 reduced the disease incidence by 20% only in Falat cultivar. Strains M1R1 and H1R1 decreased the disease severity by 52. 93 % and 10. 60 % in Superluna and 47. 90 % and 42. 88 % in Falat cultivars, respectively. Strain M1R1 increased the growth parameters, including fresh and dry weight, and height of the inoculated plants significantly in comparison with control. These results indicated that rhizospheric fluorescent pseudomonads could be effective agents in the biocontrol of tomato bacterial wilt and canker disease.

The monotypic genus Thaumatorymus Ferriè re and Novicky, 1954 (Hymenoptera: Torymidae) is endemic of the West Palaearctic subregion. Thaumatorymus notanisoides, a species rarely sampled, is recorded for the first time from Iran, expanding its known distribution range in the subregion. A brief diagnosis, illustrations and geographical distribution are provided.

Whiteflies are becoming a very serious menace and have shown resistance to many synthetic insecticides since early 1980s. The greenhouse white fly, Trialeurodes vaporariorum (Westwood) is one of the most significant pests in many horticultural and greenhouse crops worldwide. Currently, it is controlled by chemical pesticides. In current study, the best conditions for chemical control of T. vaporariorum on gerbera applying Confidor ® , Palizin ® and Proteus ® were investigated. The experiment was performed in a commercial greenhouse in Pakdasht, Tehran. The same size and not yet flowering gerbera plants in pots were selected for further analysis. Before the experiment, the numbers of nymph and adults were counted in order to evaluate application effect on their population. Each pot was covered by insect-proof net, separately. Selected factors included: the pesticide in three levels, pesticide dose in three levels (0. 5, 1 and 1. 5 ml/l), application time in three levels (at 8, 12 and 16 O’ clock) and replications in a month in three levels (2, 4 and 6 times). The experiment was conducted on the basis of Response Surface Method with central composite design to optimize the chemical control condition. Data were analyzed using Design Expert 10 software. The mortality percentage model for adults was predicted. Based on the predicted model, the optimum conditions for controlling greenhouse whitefly in gerbera commercial greenhouses were obtained. Optimal conditions with the less replications, which was two, were predicted with the dose of 0. 5 to 0. 7 ml/l up to the time at 10 or dose of 1. 5 ml/l at the time 16 using Proteus.

Tomato leaf miner, Tuta absoluta (Meyrick), is a serious pest of the greenhouse in Iran. Chemical control is the main method in high infestation conditions to deal with this pest. In this study, the efficacy of five insecticides from different groups consisting of abamectin, spinosad, imidacloprid, indoxacarb and cypermethrin was examined on the egg, larvae and adult stages of T. absoluta in laboratory conditions. The LC50 values of the insecticides were estimated at the larval stage. The results showed that abamectin had the most and imidacloprid had the least ovicidal effect. None of the tested insecticides had a satisfactory effect on the adult stage. The maximum adulticide impact was 40% for spinosad. Abamectin with 0. 45 mg ai. l-1 of LC50 value had the most toxicity and imidacloprid with 980 mg ai. l-1 of LC50 value had the least toxicity on the third instar larvae. According to the findings, abamectin and spinosad had the highest toxicity against three developmental stages (egg, larvae and adults) of the pest and can be used in infested tomato fields, when all life stages of T. absoluta are present at the same time. Meanwhile, it is recommended to use selective insecticides such as indoxacarb, when natural enemies are very active or the population of the tomato leaf miner is mostly at the larval stage.

The present study provides information about parasitoid wasps of the family Encyrtidae (Hymenoptera: Chalcidoidea) collected from south of Kerman province. The specimens were caught using Malaise traps during April to September 2017. Totally 16 species belonging to 10 genera of encyrtid wasps were collected and identified. Among them, Cerchysiella Girault, 1914 and Charitopus Foerster, 1856 are new generic records for the fauna of Iran. Four species viz. Charitopus manukyani Sakhnov, 1993; Cheiloneurus submuticus Thomson, 1876; Mayridia myrlea (Walker, 1838) and Prionomitus tiliaris (Dalman, 1820) were recorded for the first time from Iran. Diagnostic characteristics are mentioned for the newly recorded species. In addition, biological associations as well as geographical distribution for all reported species are presented. An updated list of encyrtid wasps of Kerman province is also cataloged.

In order to introduce new chemical weed management program in maize weed control in Iran, a study was conducted during 2014 and 2015. Experiment were carried out in a randomized complete block design with three replications. 15 treatments of the common maize herbicides, including nicosulfuron, foramsulforon, eradicane and 2, 4-D + MCPA were applied in their recommended doses, moreover the treatments related to cycloxydim with dicamba + tritosulfuron were used with different doses and in different times along with two control treatments (weedy and weed-free). Treatments contained 75-150 g a. i. ha-1 of cycloxydim, showed similar results with the common treatments including nicosulfuron, foramsulforon, eradicane and 2, 4D + MCPA. However, treatments with high doses of cycloxydim, had a significant reduction in weed density and weed biomass. There were no significant differences between the effects of treatments on maize grain yield and biomass. Despite the acceptable weed control of the combined treatment of cycloxydim with dicamba plus tritosulfuron, maize canopy could overcome weed growth. Based on the results and by considering cycloxydim efficacy in controlling perennial grassy weeds in maize plantation, this chemical is a suitable option during different growing stages of weeds and maize. Finally, the application of 200-300 g a. i. ha-1 of cycloxydim combined with dicamba plus tritosulfuron was the best option from an economic and environmental safety points of view.

This study aims to elucidate the relationship between the larval armyworm Spodoptera litura F. population density (0, 2, 4, and 6 per plant) with leaf damage level and yield loss in three soybean varieties, Anjasmoro, Argomulyo, and Grobogan. S. litura larvae were introduced both in the plant’ s vegetative phase (20 and 30 days after planting) and its generative phase. This research used a split-plot design with the varieties as the main plots and the larval population as the subplot, with five replications. The results showed that the highest leafdamage was in the Anjasmoro, 6. 5% to 8. 87% in the vegetative phase and 6. 95-7. 81% in the generative phase. Meanwhile, Argomulyo had 5. 96% to 6. 68% and 5. 78% to 6. 39% of damage in both phases, and Grobogan was less susceptible, with 5. 90% to 5. 98% and 5. 28% to 6. 17% at the vegetative phase and generative phase, respectively. The highest decline in seed yield was in Argomulyo (0. 81% and 0. 79% in the vegetative and generative phase) and the lowest was Anjasmoro (0. 66% and 0. 64% in the vegetative and generative phase). For the population density, the highest level of soybean varieties seed yield loss in South Sulawesi was with 6 larvae per plant, which was at 23. 44% in the vegetative phase and 23. 48% in the generative phase. Among the varieties, the highest of seed yield loss was with Argomulyo (14. 93%) and the lowest at Anjasmoro (11. 30%). It can be concluded that the relationship between the S. litura larvae population density and the decrease of seed yield is quite strong (90. 2% to 96. 4% for vegetative phase and 94. 8% to 96. 4% for generative phase).

Criconema iranicum n. sp. was recovered from the rhizospheric soil of date palm in Khuzestan province, southwest Iran, and described and illustrated based upon morphological and morphometric data. The new species is characterized by 435-515 µ m long females having a lip region with two annuli, the first labial annulus slightly wider than the second annulus, 76. 5-84. 0 µ m long stylet with anchor-shaped knobs, vulva closed, its anterior lip not curving over the posterior lip, anus small, 5-7 annuli posterior to vulva, 16. 4-23. 0 µ m long conical tail, bearing 3-5 annuli, its terminal annulus simple or bifurcate, R = 6165, RV = 9-11, juvenile present and males absent. Morphologically, the new species looks similar to four known species under the genus viz. C. annuliferum, C. duplicivestitum, C. navarinoense and C. sanctusfrancisci. Comparisons with the four aforementioned species are discussed. This is the first species of the genus being originally described from Iran.

Organisms are often exposed to various stresses such as heat. The diamondback moth, Plutella xylostella (L. ) (Lepidoptera: Plutellidae) is a serious pest of cruciferous crops in Iran and the world. The effect of short-term temperature stress on egg stage of P. xylostella and its demographic parameters were studied under laboratory conditions. Diamondback moth eggs were exposed to 30, 35 and 40 ° C for durations of 2, 4, 6, 8 h and then returned to normal temperature condition (25 ° C). The results showed that P. xylostella eggs successfully developed to adulthood at short-term (2, 4, 6 and 8 h) high temperatures stress. The ovipositional period was significantly longer at 30 ° C for 8 h, 35 ° C for 2 h and 40 ° C for 4 h than for other periods of stress. There is a significant difference in the net reproduction rate (R0) among the shortterm high temperature stresses treatments. The highest and lowest R0 was obtained at 30 ° C for 8 and 4 h, respectively. The intrinsic rate of increase (rm) was also found to be significantly affected by stress temperatures. The rmvalue ranged from 0. 15 ± 0. 009 (30 ° C for 4 h) to 0. 22 ± 0. 004 (35 ° C for 8 h). Knowledge of the effect of temperature on demographic parameters of P. xylostella could be useful in the integrated pest management for forecasting the population dynamics of this economic pest of brassicas, thereby reducing insecticide inputs, negative environmental impacts and saving hundreds of millions of dollars annually.

Ooencyrtus fecundus Ferriere and Voegele (Hymenoptera: Encyrtidae) is a gregarious egg parasitoid of sunn pest Eurygaster integriceps Puton. Superparasitism enables a female to produce multiple progeny per host and thus reduces the time spent searching for hosts, but results in progressively smaller progeny as more individuals compete for limited resources within hosts. In this study, we tested whether gregarious development would affect the functional response of O. fecundus reared under laboratory condition (26 ± 2 º C, 50 ± 10% RH and 16: 8 L: D h). Various host densities (1, 2, 4, 8, 16 and 32 eggs) were offered to females that had developed either as single, or as twins, triplets or quadruplets within host eggs. To resolve the functional responses of these females, a total exposure time of five hours was chosen, based on direct observations of handling time and the maximum daily number of host attacks/female. Functional response of the parasitoid was type III in singleton and twin parents, and type II in triplet and quadruplet ones. However, host mortality rate was 100% in host densities ≤ 8, suggesting density independence at lower densities as expected from a type I functional response. In such circumstances, handling time is expected to be zero, but was observed to be 11. 4 to 14. 3 minutes in different treatments. These results suggest that when enough time was available to find and handle all hosts, a type II functional response resembles Type I one. Searching efficiency increased and handling time decreased with body size of the parasitoid of four categories.

Puccinia tanaceti in narrow sense is reported from British Columbia for the first time. Golovinomyces asterum var. solidaginis and G. macrocarpus are also new members for mycobiota of BC. New hosts are reported for rusts and powdery mildews in BC and Canada.

Genus and species of Dichromothrips smithi (Zimmermann) (Thripidae: Thripinae) is recorded from Iran, Ilam province for the first time. Specimens of this species have been collected on rangeland plants by beating an unknown plant over a white plate. Diagnostic morphological characters and the geographical distribution of the newly recorded thrips are given.