JOURNAL OF CROP PROTECTION
Year:2019 | Volume:8 | Issue:2 |Papers Count:10

The decline of biodiversity, specifically of insects is one of the major topics in conservation biology. In several countries of Europe, recent studies have shown a severe decline in species number and biomass of insects. In most countries of much higher diversity, much less is known about the state of the insect fauna. In this study, we focus on the acridid grasshoppers of Iran as an indicator taxon for diversity decline in a high diversity region. We used data of two surveys to suggest a change in species number between 1963 and after 2000. In the surveys before 1963, the species diversity across multiple localities in Iran was much higher compared to more recent faunistic studies. While this data is not statistically analyzable as the sampling is not completely comparable, the trends show a clear pattern of decline, which likely reflects the reality, conforms well to individual observations of less frequent encounters in the field and matches global patterns of insect decline. However, more standardized quantitative surveys are needed to generate statistically analyzable data. Potential reasons for the observed decline are severe draughts as a result of global climate change, habitat pollution, and destruction for construction and mining and especially overgrazing. Management actions need to be urgently put into place to stop the negative trends. Future studies need to document and test if these are taxon-specific trends or universal patterns in the region.

Spectroscopy in visible and part of near infrared region was assessed as a non-destructive technique for the detection of plants infected with Potato virus Y (PVY),The aim of our research was to recognize spectral signatures that indicate PVY infected plants,In this assay,we studied spectral reflectance of potato leaves showing different PVY symptoms in cultivars Agria and Milva,Virus titer of leaves that showed different disease symptoms,were estimated using enzyme-linked immune sorbent assay,The means of spectral data obtained from different leaves in each experimental plant were used for spectral analysis,Analyses showed that spectral region in 900-1100nm was markedly sensitive to the PVY infection and could be useful for developing a good spectral signature for detection of the infection,Based on the X loading weights obtained from principal component analysis (PCA),sensitive wavelengths were screened,some wavelengths in this region have most positive or negative loading and based on linear discriminant analysis,they could discriminate infection status with high accuracy,The reflectance variation in this region is related to changes in cell structure and water activity due to viral infection,Results indicate that spectroscopy has a suitable potential to detect virus-infected plants;which could be further developed for more accurate potato field inspection aimed at controlling the spread of viral infection,

The cotton bollworm, Helicoverpa armigera (Hü bner) is an important pest of many crops. Here, effects of kaempferol on ecdysteroid titer in the ovaries, hemolymph andoocyte size via tachykinin-4 content of H. armigera were studied. Third instar larvae of H. armigera were fed on artificial diet containing different concentrations of kaempferol for 8 days. Kaempferol had insecticidal activity after 6 days. The highest level of larval mortality was approximately 36% in larvae fed diet containing 10μ g/g of kaempferol for 8 days. Competitive ELISA showed that tachykinin-4 titer decreased clearly in the adult female moth's brain and hemolymph which fed on diet containing 5 and10μ g/g kaempferol during their larval stage for 8 days. It also decreased ecdysteroid in the ovary and hemolymph of adult female. Moreover, oocyte size was significantly decreased. On the other hand, the injection of tachykinin-4 into the hemocoel not only increased ecdysteroid titer in the ovary but also approximately 1. 4 fold increases in oocyte size was observed. In conclusion, feeding on food containing kaempferol decreased tachykinin-4 level in the brain and hemolymph that itself led to decreasing ecdysteroid titer in the ovary and hemolymph. Finally the decrease in ecdysteroid titer resulted in smaller oocytes.

Cucumber mosaic virus (CMV; genus Cucumovirus, family: Bromoviridae) has the widest host range of any known plant viruses. Seven virus isolates, originated from different ornamental plant species and greenhouses, were biologically purified, mechanically inoculated onto test plants and their serological differences were assayed based on reactivity with 11 CMV-specific monoclonal antibodies. Following total RNA extraction, coat protein (CP) coding region of CMV isolates was amplified. Based on biological, serological and phylogenetic analysis, only one isolate belonged to CMV subgroup II and other six isolates were equally distributed among the two IA and IB subgroups. Aphid transmission assay showed that no significant difference was observed between transmission efficiency of CMV subgroups IA, IB and II members by Aphis gossypii. The genetic variation and evolution of CMV in Iran was studied by sequence analysis of the CP gene and comparison with equivalent sequences of isolates from other continents that exhibited low genetic diversity and close evolutionary relationships among isolates in subpopulations. Analysis of various population genetics parameters and distribution of synonymous and nonsynonymous mutations revealed that most of the amino acid sites were under negative selection and only one site was under positive selection.

The legume crops such as chickpea and lentils are mainly cultivated in semi-arid tropical lands. Chickpea chlorotic dwarf virus (CpCDV) causes major losses to legumes throughout the world. Producing of specific antibody against this virus is crucial for surveys of disease in the fields and assessment of vial resistance in plant cultivars. Present article describes developing of specific antibody against the CpCDV virus by applying recombinant protein. In this study, coat protein of CpCDV was selected as a target for detection and preparation of polyclonal antibody. To achieve this aim CP gene encoding coat protein of CpCDV was initially PCR-amplified and inserted into bacterial expression vector. Expression of recombinant protein was performed in Bl21 strain of Escherichia coli. Purification was carried out under native conditions and the accuracy of recombinant protein production was confirmed by electrophoresis. The purified recombinant coat protein of CpCDV was used for immunization of rabbit. Purification of immunoglobulin molecules was performed by affinity chromatography using protein A column followed by conjugating of IgG to alkaline phosphatase enzyme. The capability of purified antibodies and conjugates for efficient detection of infected plants was assessed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), western blotting and dot immunosorbent assay (DIBA). These results proved that prepared IgG and conjugate are able to distinguish with high efficiency CpCDV infected plants. To the best of our knowledge, this is the first report for production of anti-CpCDV antibodies raised through recombinant protein technology.

The potato cyst nematode Globodera rostochiensis (PCN) causes severe damage to potato production worldwide. The stimulatory effects of root diffusates of 9 plant families on hatch of second stage juveniles (J2) of PCN and their possible use as trap crops were studied. In the laboratory, cysts were placed in leachates from roots and hatched J2s were collected weekly; in addition, the selected plants were grown in soil for 3 months and the rates of decline of eggs from inoculated cysts, were determined in two experiments with various plant species. Species of Solanaceae, such as the susceptible potato cultivar Marfona, tomato and the resistant potato cultivar Agria, induced 84%, 75% and 65% hatch respectively. Moreover, considerable hatching (49%-70%) was caused by exposure to root exudates of weeds of Solanum nigrum and S. villosum. Among non-host and non-Solanaceae plants, 11-32% of J2s hatched in root exudates of treatments of wheat, corn and barley in soil. There were differences in the rates of decline of J2 populations caused by the different plant species examined. In S. sisymbriifolium (a non-host species of Solanaceae) treatment, the density of encysted eggs declined by 62%. The potential of aforementioned plant species, the resistant cv Agria and some other tested plant species as suitable trap crops are further discussed; and in conclusion, the use of the trap crops could be an important component of PCN management program in Iran.

The antibiosis, host preference in free-choice situation, and digestive enzyme activity of Brevicoryne brassicae L. (Hemiptera: Aphididae) were evaluated in the laboratory (25 ± 1 ° C, 60 ± 5% R. H. with a 14-h day) on nine host plants: broccoli, canola (leaf, flower, and pod), cauliflower, kohlrabi, radish, red cabbage and white cabbage. The antibiosis test was based on life table parameters and the experiment started with 50 replicates for each host plant using clip cages. The immature survival varied from 34% on red cabbage to 78% on cauliflower. The viviparous aphids reared on rapeseed (flower) had the highest GRR and R0 values, and those on red cabbage had the lowest GRR and R0 values. Also, aphids reared on rapeseed (flower) had significantly higher rm value. The lowest rm value was obtained when individuals fed upon red cabbage. In host preference experiment, rapeseed (leaf) attracted the significantly higher number of adults as opposed to radish, which attracted the lower number of adults. Females who came from nymphs reared on rapeseed (flower) were heavier than other hosts. The growth index of nymphs varied from 0. 035 to 0. 103, with the minimum on red cabbage and the maximum on cauliflower. The amylolytic activity in adults was higher on rapeseed (flower) and the lowest on red cabbage. In addition, the highest and lowest proteolytic activity was on rapeseed (flower) and red cabbage, respectively. The results of this study indicated that red cabbage was an unsuitable host for feeding of B. brassicae.

The efficacy of sex pheromone traps for detection of Cydalima perspectalis (Walker) (Lepidoptera Crambidae) was assessed in 2017 in Cheshmeh-Bolbol Box Reservoir (Golestan province, Iran). Monitoring was done from May to September and three flight peaks were determined. No significant difference was observed between colors as well as heights of installing pheromone Traps for capturing C. perspectalis. The results confirmed the efficiency of pheromone traps in decreasing damages of Box tree moth. Also, best time for chemical and pheromone control was assessed.

The objective of this work is to determine the chemical composition of essential oils of four Cupressaceae species and to bring out some of their antimicrobial activities. For this purpose, the extraction of essential oils was carried out by hydrodistillation and the obtained oils varied from 0. 4% to 0. 91%, with a better yield for Cupressus sempervirens equal to 0. 91%. The chromatographic analyses revealed that the chemical composition of Juniperus phoenicea, Juniperus oxycedrus and C. sempervirens is largely dominated by monoterpenes at rates higher than 34% with majority of α-pinene like component. In addition, the results of the antibacterial activity showed a significant inhibitory effect of essential oils, particularly those of J. phoenicea was found to be the most active with values of Minimum Inhibitory Concentration (MIC) equal to 50μ g/ml. Moreover, the mycelial growth inhibition confirms that essential oils of J. phoenicea and J. oxycedrus are most effective, with values of MIC equal to 1000μ g/ml for both. These antimicrobial properties would be due to the richness of these essences in bioactive compounds such as the terpenoids, polyphenols and alkaloids known for their implication in the plants selfdefense. Consequently, the inhibitory effect of these essential oils on the microbial development suggests prospects for their application as natural and safe alternatives to synthetic compounds for plant protection.

Among specimens collected from West Azerbaijan province-Iran, during 2011-2017, fourteen species of the genus Megaselia Rondani 1856 were identified. Twelve species (Megaselia aculeata (Schmitz, 1919), M. annulipes (Schmitz, 1921), M. brevicostalis (Wood, 1910), M. giraudii (Egger, 1862), M. hendersoni Disney, 1979, M. hirticaudata (Wood, 1910), M. meconicera (Speiser, 1925), M. minuta (Aldrich, 1892), M. pleuralis (Wood, 1909), M. plurispinulosa (Zetterstedt, 1860), M. subnudipennis (Schmitz, 1919) and M. verralli (Wood, 1910)) are being newly reported from Iran. A key to the studied species along with their geographical distributions and supplementary figures are given.