نشریه گیاه پزشکی کاربردی
سال چهارم شماره 4 (پیاپی 16، اسفند 1394)

Root knot nematodes (Meloidogyne spp.) is one of the most important pathogens of tobacco almost in all tobacco-growing areas. The effect of two nematicides, Cadusafos10G and Fenamiphos10G to control root knot nematode Meloidogyne incognita in pot condition were investigated in this study. Experiments were carried out in a completely randomized design with 20 treatments and 4 replications included two nematicides at three dosages of 40, 60 and 80 Kg/ha and in three application times. Each pot was inoculated by 3000 second stage juveniles (SJ2) and eggs per kg soil of pots. Two controls were considered for the experiments: nematode infested soil (no nematicide) and control check of no infested. The effect of the nematicides were evaluated by the number of nematodes in root and soil, gall index, number of egg masses, average eggs number per egg mass, reproduction factors(Rf) after seventh harvesting stage at the end of growing season (3 month after transplanting). The growth factors measured, were included the fresh and dry weight and number of leaves, height of shoots, fresh and dry weight root, and length of root, income and average price. There was significant difference among treatments except fresh weight and number of leaves and plant height. Nemacure 80 Kg/ha had the best efficiency in controlling the root knot nematode (M. incognita) in tobacco and the best time of its application was one week prior to transplanting.

Cytochrome P450 (cyp) enzymes are heme-containing monooxygenases that catalyze metabolisms of various endogenous and exogenous compounds. They constitute a superfamily of enzymes present in various organisms including mammals, plants, bacteria, and insects. cyps are diverse and metabolize a wide variety of substrates, but their structures are largely conserved. In this study, bioinformatic analyses of P450 enzymes were performed in 30 insect species from different families. According to the conserved motifs obtained by MEME and MAST tools, three motifs were common in all insect species. The structural analyses of seven selected species of insects were investigated by ProtParam and SOPMA tools in ExPASy database. Tertiary structure of Drosophila melanogaster (Accession code: NP_525031) as an insect sample and six samples of other species were predicted by Phyre2 server using “c4lxjA” model (PDB accession code: 4lxj). The protein sequences were aligned with ClustalW algorithm by MEGA 6.06, and phylogenetic tree was constructed using the Neighbor-joining (NJ) method. According to the results, there is a high similarity among cyp proteins of different species in insects so that they should be derived from a common ancestor. The obtained data provides background of bioinformatic studies for the function and evolution of this protein in insects.

With about 4500 species, the Tephritidae is one of the most important families of acalyptrate Diptera. Most species are phytophagous and cause economical damage to agricultural crops and some of them effectively used in biological control programs against weeds. During studies on tephritid flies fauna in Gilan Province (Iran) in 2013–2015, 19 species of 11 genera are found to occur in this region. 17 species are recorded for the first time from Gilan province. The list of 25 species of fruit flies that occur in Gilan province is provided.

Colorado potato beetle Leptinotarsa decemlineata Say has numerous hosts as a serious potato pest. There are several biological control agents which are used to control the pest and Bacillus thuringiensis can be the most important. In order to estimate the LC50, this study started by the bioassay performed with the standard cultured isolate from the Custom BC sample. The concentration killing 50% of larva population was assessed as 2506.63 CFU/ml. Probit statistical software was used to show the difference among native and standard isolates in a complete random design. Two native isolates (KH4 and GN9) were used as treatments. The variance analysis and comparing the mean mortality percentage of Colorado potato beetle in second instar larvae demonstrated a significant difference between treatments and the standard isolate in all the concentrations. The standard isolate had the highest mortality percentage of 62% and the native isolates showed less than 5% of mortality. It is understood that the selection of the proper concentration (about LC50) and comparison of the mortality percentage in that concentration is an appropriate method for the screening the isolates and make a lot of time and money saved.

The use of chemicals is one of the most effective, fastest and accessible ways to control plant diseases. Due to their environmental pollution, harmful to humans, and the occurrence of pathogens resistance, the researchers look for alternative ways to control plant diseases. Currently, the use of plant extracts is as one of the modern methods to control plant pathogenic pathogens. Because plant extracts have natural origin, they could not cause environmental pollution. Moreover, these compounds have great potential to use in plant disease management. Plantextracts have been used against different pathogenic agents such as fungi, bacteria and nematodes, and the results of their applications have been successful. This review summarizes the previous studies that have used plantextracts as biological agents to control plant pathogenic pathogens and their biocontrol efficacy

Plants produce a large number of anti-fungal materials. Many of these compounds are structural and are present in plants normally. The pathogen can cause disease that pass of the barrier of these compounds. On the other hand, there are compounds in plants that are inactive in the normal mode, this compounds was called phytoalexins. The phytoalexins are broad spectrum inhibitors and are chemically diverse with different characteristic types of particular plant species. Phytoanticipin distribution in plants often performed specifically and the concentration of these compounds in the outer cell layers of plant tissues were high. Studies on phytoanticipins are often done by focusing on the mutant plants. Phytoanticipins are divided in two groups, compounds with low and high molecular weight. Low molecular weight compounds include phenols and quinones, the unsaturated lactone, sulfur compounds, saponins, cyanogenic glycosides and terpenoids. High molecular weight compounds including tannins and proteins. In this study, it was studied the compounds plant defense against pathogen stress.