Journal Of Crop Protection
Volume:3 Issue: 1, Mar 2014

Microcerotermes diversus Silvestri (Isoptera: Termitidae) is the most economically destructive wood pest in structures in Khuzestan province (Iran). Chemicals such as essential oils and plant extracts that are compatible with the environment and have high potential to be used in integrated pest management programs are extremely important. This study evaluated contact and digestive toxicity of Eucalyptus camaldulensis Dehneh. (Myrtaceae)essential oil in no-choice and choice bioassays and feeding inhibition trials on M. diversus. Concentrations of the essential oil ranged from 0.3 to 1.6% (g ml1). The results of the choice tests and feeding inhibition trial showed that the essential oil could act as a repellent at 0.7% concentration. Concentrations used in these tests resulted in mortality of termites, and a direct relationship between concentration and mortality was observed. The essential oil also increased the mortality of termites at concentrations higher than 0.7%. Termite feeding decreased with increased in concentration. Due to the ability of termites to choose the untreated filter-paper in the choice trial, values of LT and LC, were higher than in no-choice trials. The highest effects of Eucalyptus essential oil (≈100% mortality) was induced by the concentration 1.6%. Overall, this study reveals that Eucalyptus essential oil may be suggested as an effective toxicant with suitable contact and digestive toxicity on M. diversus.

Six belonolaim species were collected from grasslands of Sabalan region. The found species belong to genera Amplimerlinius, Merlinius, Nagelus, Neodolichorhynchus, Paramerlinius and Tylenchorhynchus. Among the found species, Neodolichorhynchus judithae is reported for the first time from Iran and is characterized byhaving offset head, cuticule with 16 longitudinal ridges, delicate stylet 21-23 µm long, presence of post intestinal sac and tail with annulated terminus.

Xanthomonas campestris pv.musacrearum causes Banana wilt disease (BXW disease) which which occurs at different epidemic phases in East and Central Africa (ECA). In the endemic areas, there are many banana fields with over 80% BXW disease incidence. This study aimed at rehabilitating banana fields heavily infected with BXW disease in Uganda, Kenya and DR. Congo. Farmer managed trials were established in BXW disease hotspots in western Kenya and DR. Congo, while in Uganda, similar trials were established at community level i.e. clusters of at least 200 heavily infected banana fields. The control options evaluated included single stem removal, suspension of pruning in affected fields, male bud removal and disinfection of tools with fire or Sodium hypochlorite. Data was collected on the proportion of affected fields (BXW disease prevalence), BXW disease incidence and the number of banana bunches sold at 3-month intervals. BXW disease incidence reduced by over 80% in 11 months in Kenya and DR. Congo, resulting in yield recovery by up to 70% within one year. In Uganda, the proportion of farmers that effectively controlled BXW disease increased 5% to 60% within a year in some hotspots. Consequently banana sales recovered up to 30% in some hotspots. This study demonstrates that it is possible to effectively control BXW disease within 12 months in previously severely infected fields in various area of ECA.

Brassica napus is an important oilseed crop and the yield loss due to fungal disease stem rot caused by Sclerotinia sclerotiorum is a serious problem in cultivation of this crop. The pathogenesis-related (PR) protein, glucanase, hydrolyzes a major cell wall component, glucan, of the pathogenic fungi and acts as a plant defense barrier. In this study, a β-1,3-glucanase (bgn13.1) gene isolated from the biocontrol fungus Trichoderma virens-10 (showing the high β-glucanase activity) and cloned in pUC19 cloning vector. The cloned fragment was confirmed by molecular analysis and showed to contain two short introns, 52 and 57 bp and an open reading frame coding 761 amino acids. The bgn13.1 gene was over-expressed under the CaMV35S promoter in B. napus, R line Hyola 308. Transformation of cotyledonary petioles was achieved by pBIKH1 containing bgn13.1 gene via Agrobacterium tumefaciens LBA4404. The insertion of transgene was verified by the polymerase chain reaction (PCR) and genomic DNA Southern dot blotting in T0 generation. RT-PCR analysis indicated that the transgenic canola plants were able to transcribe the β-1,3 glucanase gene. Also, we used transgenic over-expression approach in order to investigate antifungal activity of expressed Bgn13.1 on S. sclerotiorum. The heterologous expressed Bgn13.1 of line # 7 and line # 10 compared with other lines showed stronger inhibition against hyphal growth of S. sclerotiorum with inhibition rate of 35.2% and 32.8%, respectively.

The diamondback moth, Plutella xylostella (L.) is a serious and economically important pest of cruciferous crops worldwide. The nutritional indices of this peston four host plants including two canola (SLM046 and RGS003) and two cabbage cultivars (Green-Cornet and Glob-Master) were determined under laboratory conditions (25 ± 0.5 °C, 65 ± 5% RH and 16: 8 L: D h). The highest relative consumption rate (RCR) and relative growth rate (RGR) were recorded on RGS003 (95.68 ± 14.52 mg/mg/day) and SLM046(0.382 ± 0.041 mg/mg/day), respectively. The efficiency of the conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were significantly highest on SLM046 (2.298 ± 0.646 and 2.471 ± 0.719%, respectively). However, there was no significant difference among cultivars regarding approximate digestibility (AD) index. The highest feeding performance of the larvae of P. xylostella was found on SLM046. The nutritional indices are appropriate tools in host plant resistance evaluation and they also could provide profound understanding of the behavioral and physiological bases of insect-host plant interactions.

Black stem is one of the most important fungal diseases of sunflower which caused by Phoma macdonaldii. This research was conducted to clarify the interactions between a few breeder lines and wild-type accessions of sunflower with seven isolates of Phoma macdonaldii, the causal agent, under controlled conditions. The experiment was carried out in randomized complete block design with three replications. Each replication consisted of 30 seedlings. Twenty micro liters of spore suspension was deposited at the intersection of the cotyledon petiole and hypocotyl of four-leaf-stage sunflower seedlings as well. Three, five and seven days after inoculation, seedlings were scored on a 1-9 scale for percentage of necrotic area. Highly significant differences were observed among genotypes, isolates and their interactions for disease severity 7 days after inoculation based on AUDPC (Area Under Disease Progress Curve) values. Two models of GGE biplot including Isolate-based and genotype-based models were used to study the pathogenicity of the isolates and susceptibility of sunflower, respectively. Isolate-focused biplot revealed that there was a considerable difference between virulence of isolates. Based on genotype-focused biplot model, accessions including 665 Iowa, 1012 Nebraska, 211 Illinois and 1016 Nebraska were more resistant to studied isolates of P. macdnaldii. Results revealed that GGE biplot approach could lead to good understanding about interactions between sunflower genotypes and Phoma macdonaldii isolates.

Morphological and morphometric characters of two species of superfamily Sphaerularioidea, recovered in southwestern Iran namely Deladenus durus and Prothallonema obtusum are given. The recovered specimens of D. durus are characterized by having a valvular chamber in metacorpus and excretory pore posterior to the hemizonid.The Iranian population of P. obtusum is characterized by having four lines in the lateral field, excretory pore anterior to the end of pharynx, not bulgy vulva region and short subcylindrical tail.

A survey was conducted on the fauna of the hover flies in Northern Iran in 2011. Among the collected and identified material, the genus Temnostoma Le Peletier & Serville, 1828represented by a single species, T. vespiforme (Linnaeus, 1758) is newly detected in Iran. Diagnostic characters and geographical distribution of the newly recorded species is briefly discussed.

A survey on cereal fields of Khuzestan province during 2008-2011 revealed that cereal cyst nematodes (CCNs) are widely distributed in this region. The CCNs were present in 37 and 35% of the 200 samples collected from wheat and barley fields respectively. The species were identified as Heterodera avenae type B and H. filipjevi which the morphological and morphometric identification were confirmed by rRNA-ITS RFLP. Population density of CCNs ranged from 2 to 103 cysts (mean 18)/100 g of dried soil with an average of 395 (0-3400) J2 and eggs in wheat samples. Whilst the number of cysts in barley samples were counted 3-71 cysts (mean 11) /100 g soil, the J2 and eggs averaged 166 (0-900). The lowest and the highest rate of infestation were observed in the regions of Ahvaz and Behbahan with 8 and 83 % respectively. The number of J2 and eggs of CCNs in some regions were greater than damage threshold level considered for the CCNs and it is likely they could cause economic yield loss in these regions.

The toxicity of imidacloprid and pirimicarb for all stages of the melon aphid, Aphis gossypii Glover, were investigated under laboratory conditions (25 ± 1 oC, 65 ± 5% R.H. and a photoperiod of 16:8 (L: D) h.) using a leaf dipping method. These pesticides were very toxic for first instar nymphs of A. gossypii with LC50 values of 17 and 220.2 ppm for imidacloprid and pirimicarb, respectively. For other nymphal instars, values of 23.9 to 70.5 ppm and 308.8 to 781.7 ppm were recorded for imidacloprid and pirimicarb respectively. Their LC50 values for adults were 90.1 and 983.1 ppm, respectively. Toxicity decreased with increasing age. Imidacloprid was more toxic than pirimicarb for all stages of development. The effect of applying sublethal concentrations of imidacloprid and pirimicarb was evaluated, also, using demographic toxicology. Longevity and population growth parameters, including intrinsic rate of increase (rm), net reproductive rate (R0), generation time (Tc) and finite rate of population increase (λ), were affected negatively by both insecticides. The rm values for control, imidacloprid and pirimicarb exposed populations were 0.438, 0.150 and 0.335 female offspring per female per day, respectively. The doubling time (DT) also, was affected by imidacloprid. Overall, these results suggest that imidacloprid and pirimicarb can be effective against A. gossypii.

Four genera and five species of Idolothripinae are recorded in Iran: Allothrips Hood, Compsothrips Reuter and Pseudocryptothrips Priesner each with one species, and Megathrips Targioni-Tozzetti with 2 species. In this paper, the genus Nesothrips Kirkaldy, with one species N. brevicollis (Bagnall) collected on grasses in Marivan, Kurdistan Province, is recorded in Iran for the first time. A key is provided to distinguish five Idolothripinegenera from Iran. Diagnostic morphological characters and geographical distribution of the newly recorded species are briefly discussed.

In this study two Bacillus pumilus including ToIrFT- KC806241 and ToIrMA-KC806242 were obtained from tomato fields and characterized based on phenotypic and molecular properties. Their possibility to reduce root knot disease of tomato causes by Meloidogyne javanica was evaluated. The experiments were done in lab and under pot conditions. Application of the ToIr-MA against M. javanica reduced the number of galls and eggs. Preliminary results indicated that the ToIr-MA has an ability to produce proteolytic enzymes in lab conditions. It seems that the bacterial culture filtrates can suppress egg hatching and increase juvenile''s mortality, but the role of these metabolites in disease suppression needs to be investigated further. Significant enhancement in root and shoot length (33%) and dry root and shoot weight (64 and 67%) was also recorded over usage of strain ToIr-MA in comparison to untreated controls. Additionally, survival of bacterial strains in rhizosphere and increases in population density were seen using root colonization assay. To our knowledge, this is the first time that such B. pumilus strain with nematicidal activity against M. javanica has been reported in Iran which may suggest to manage disease and change microbial population dynamics in the rhizosphere.