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A survey of 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 the morphological and morphometric identifications of which 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 rates of infestation (8 and 83%) were observed in the regions of Ahvaz and Behbahan respectively. The number of J2 and eggs of CCNs in some regions were greater than the damage threshold level considered for CCNs and it is likely they could cause economic yield loss in these regions.  

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Entomopathogenic nematodes (EPNs) are commonly used as biological agents for control of insect pests. This study was carried out to identify EPNs, determine dominant and frequent species in Kurdistan province, Iran and characterize their symbiotic bacteria. Identification of EPNs was performed based on morphological and morphometrical characters and also rRNA-ITS gene sequences. Two EPNs, Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) and Steinernema feltiae (Rhabditida: Steinernematidae) were identified. Out of totally 150 soil samples collected mainly from mid-southern parts of the province, 60% were positive for EPNs. Heterorhabditis bacteriphora showed the highest frequency in this region, remarkably 59.3% of soil samples contained this species. Incidences of H. bacteriphora in grasslands, woodlands and alfalfa fields were 57.3, 14.6 and 28.0 percent, respectively. Steinernema feltiae was found only in alfalfa fields with 0.66% frequency. Bacterial symbionts of H. bacteriophora and S. feltiae were also identified based on biochemical characters and recA gene sequencing. In this research, two species of Photorhabdus were isolated from H. bacteriophora namely P. luminescens subsp. kayaii and P. temperata subsp. thracensis. Xenorhabdus bovienii was identified from infective juveniles of S. feltiae.

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Pieris brassicae L. is one of the most important pests of Brassicaceae. The insecticidal effect of two entomopathogenic nematodes (EPNs), Heterorhabditis bacteriophora and Steinernema feltiae, was determined through their interaction with Beauveria bassiana and Bacillus thuringiensis subsp. kurstaki (Btk) against P. brassicae. In the interaction tests, the EPNs were applied at LC₅₀ level 0, 12 or 24h after treating the larvae with LC₁₀ or LC₂₅ of the B. bassiana or Btk. The interaction between the EPNs and B. bassiana was entirely different from the interaction of the EPNs and Btk. The interaction with B. bassiana was dependant on time intervals, while the interaction of the EPNs with Btk was almost additive or synergistic. An antagonistic effect was seen when the EPNs were applied immediately after the B. bassiana. However, the application of the EPNs 24h after their treatment with B. bassiana caused additive or synergistic effects. The results also showed the best mortality effect when the EPNs were used with Btk at 12 h and 24 h time intervals. Based on the results, a simultaneous use of the EPNs and B. bassiana is not recommended against P. brassica. However, the EPNs could be used simultaneously after Btk but it is better to allow a time interval to increase mortality.

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To identify the Cereal Cyst Nematodes (CCN) and their distribution and population density in wheat fields in Chaharmahal and Bakhtiari Province based on interpolation by geographic information system, a total of 212 composite soil and root samples were randomly collected from different wheat fields of nine districts of the province during 2013-2014. The soil samples were explored for number of cysts, second-stage Juveniles (J2) and eggs. The species were identified based on morphological, morphometric and molecular characteristics. Analysis was performed by Arc GIS software using interpolation technique for determination of raster map. The results showed that 42% of soil samples were infested with Heterodera filipjevi containing an average of 994 eggs and J2 per 200 g of soil. The maximum infestation was observed in Dehsahra region in Lordegan district with an average of 4720 eggs and J2 per 200 g soil. Wheat fields of Kohrang, Kiyar and Farsan districts showed low population density while moderate infestation was observed in Ardal, Ben, Saman and Borujen districts. Instead high population density of H. filipjevi was found in Shahrekord and Lordegan. Based on interpolation of population density and interpolation maps, the eastern part of Shahrekord and southern and western parts of Lordegan districts were predicted as regions with high infestation to H. filipjevi and considered as hotspots for this disease.

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