PLANT PEST RESEARCH
Year:2012 | Volume:2 | Issue:1|Papers Count:8

During 2009-2010, a survey was carried out to study the fauna of raspberry shrubs phytoseiid mites in central area of Guilan Province. During this study, 19 species belonging to 8 genera and 3 subfamilies were collected and identified. The list of identified species is as follows. New species for Guilan Provine mite fauna are marked by an asterisk (*). Also, an identification key for phytoseiid mites of raspberry shrubs in Guilan province is provided.Subfamily Amblyseiinae: Transeius wainsteini (Gomelauri, 1968); Transeius herbarius * (Wainstein, 1960); Amblyseius herbicolus (Chant, 1959); Proprioseiopsis okanagensis * (Chant, 1957); Amblyseius rademacheri(Dosse, 1958); Neoseiulus umbraticus (Chant, 1956); Neoseiulus sugonjaevi * (Wainstein and Abbasova, 1974); Neoseiulus marginatus (Wainstein, 1961); Neoseiulus barkeri Hughes, 1948; Neoseiulus tauricus* (Livshitz and Kuzenetsov, 1972); Neoseiulus multiporus * (Wu and Li, 1978) and Euseius amissibilisMeshkov, 1991. Subfamily Phytoseiinae: Phytoseius plumifer (Canestrini and Fanzago, 1876); Phytoseius juvenis Wainstein and Arutunjan, 1970 and Phytoseius spoofi (Oudemans, 1915).Subfamily Typhlodrominae: Typhlodromus (Anthoseius) georgicus * Wainstein, 1958; Paraseiulus soleiger(Ribaga, 1904); Typhlodromus (Anthoseius) kazachstanicus * Wainstein, 1958 andParaseiulus triporus (Chant and Yoshida-Shaul, 1982).

Diaphorina citriKuwayama (Hemiptera: Psyllidae) is one of the dangerous citrus pests and is the vector of citrus greening disease. For introduction of the most effective insecticide, two methods were carried out in this study. At the first method, dimethoate (500 ppm), imidacloprid (500 ppm), hexaflumaron (1000 ppm), pyriproxifen (AdmiralÒ) (2000 ppm), phosalone (1000 ppm), petroleum olil (VolkÒ) (1%), Neem extract (1000 ppm) were sprayed. Second method was done with injection of oxydemeton-methyl, imidacloprid to tree trunk. Results showed that there were no significant differences between results of two years experiments (2005-5006), but there were significant differences among treatments in 3 and 7 days after spraying of insecticide at the level of 1%. Three days after spraying of insecticides the highest mortality was obtained for dimethoate (77.61%) and imidacloprid (70.49%). Seven days after spraying of insecticides, dimethoate caused 71.55% mortality. In injection method, oxydemeton-methyl and imidacloprid caused 14.13% and 15.86% mortality, respectively and results showed no significant differences between the treatments.

The spatial distribution pattern of pests can be useful in planning and performing the integrated pest management. The Konar moth, Thiacidas postica Walker (Lepidoptera: Noctuidae), is a defoliator of Konar (Ziziphus spina-christi), in south of Iran especially Bushehr, Hormozgan and Khuzestan provinces. The Larva is defoliator of Ziziphus spp. Extension of Konar cultivation in south of Iran as an economic orchards caused complete studies on some important pests. The spatial distribution of T.posticafifth instar larvae was studied in field conditions on the Ziziphus spp. during 2006-2008. A 50 cm of branches of each Konar tree was selected as sampling units. With a primary sampling sample size was determined as 40. In this research, the spatial distribution pattern of fifth instar larvae of T.posticausing regression models (Taylor’s power law and Iwao’s patchiness regression) was determined. Population density of T. postica and its parasitoid, Pales murina Mes. (Diptera: Tachinidae), was studied by Regression and Linear equation. The results showed that Taylor’s power law (R2=0.98) and Iwao’s patchiness regression, (R2=0.86), that the Konar moth larval population was aggregated on the host plant branches. As the slop of regression was significantly greater than 1, and it implies that large samples are required to obtain density estimates at an acceptable level of precision.The relationship between eating and behaviors of different larval instars fitted both Taylor’s power law and Iwao’s patchiness regression model. The slop of regression, b, was 1.99 and 3.45 for Taylor’s power law and Iwao’s patchiness regression, respectively. Then spatial distribution of fifth larval instars of T. postica on Z. spina-christi was estimated aggregated (clumped). Regression and Linear equation between mean of 5th instar larva density of T. postica and percentage of parasitism of P.murinaalso showed that parasitoid acts as a density dependent factor.

The astigmatic mites are cosmopolitan and some species are the most important pests of stored products. During 2006-2007, a faunal study was carried out to collect and identify rice stored mites in Guilan Province, Northern Iran. Infected rice samples were collected and taken to acarology laboratory Agriculture College, University of Guilan. The mites were extracted by Berlese funnel and cleared in lactophenol; they were mounted in Hoyer’s medium on microscopic slides and identified using available references. During this study, 9 species of Astigmata belonging to four families and 9 genera, were collected and identified. Among them 8 species considered to be new records for Guilan Province mite fauna which are marked by an asterisk (*). The list of identified species is as follow:AcaridaeAcarus siro* Linnaes, 1758                                              GlycyphagidaeAleuroglyphus ovatus* (Troupeau, 1878)                           Lepidoglyphus destructor* (Schrank, 1781)Suidasia nesbitti* Hughes, 1948                                       G. privatus* Oudemans, 1903Tyrophagus putrescentiae*(Schrank, 1781)                       Gohieria fusca(Oudemans, 1902)Chortoglyphidae                                                              Histiostomatidae=AnoetidaeChortoglyphus arcuatus* (Troupeau, 1879)                       Histiostoma feroniarum* (Dufour, 1839).

The lethal and sublethal effects of chlorpyrifos+oil, abamectin, and chlorpyrifos+abamectin+oil on the immature stages of Cryptolaemus montrouzieri Mulsant were investigated under laboratory conditions. Chlorpyriphos was applied at 500, 1000 and 2000 ppm with 1% oil and abamectin at 500, 100, and 200 ppm concentrations on fourth instar larvae through three exposure methods, including topical direct contact, residual contact and feeding on sprayed preys. The eggs of C. montrouzieri treated via dipping in pesticide solutions. Dipping eggs in pesticide solutions affected significantly their hatching rate, first instars larvae survival, and pupal weight. The lowest egg hatching percent (29 percent) and pupal weight (9.8 mg) were observed in chlorpyriphos 2000 ppm+abamectin 200 ppm+oil. Survival of the fourth instar larvae and pupal developmental period and weight were also significantly affected in each exposure method. The lowest survival of fourth instar larvae (50 percent) and longest pupal duration (7.0 days) were obtained in topical contact with chlorpyriphos 2000 ppm+abamectin 200 ppm+oil. In conclusion, because of the adverse effects of chlorpyriphos on the development of immature stages of the ladybird, replacing it with a safer pesticide is necessary to increase the compatibility of biological and chemical control programs in citrus orchards of northern Iran.

Boll worm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a cosmopolitan and polyphagous pest that attacks many plant species. The most important control method is based on the use of pesticides which is a concern to environment as well as insects' resistance, thus alternative ways to chemical ones are required. The aim of the current study is to investigate the effect of protein extract of triticale against boll worm amylase. To do so, fourth instar larvae were dissected, their gut removed and their amylase were extracted. Protein of triticale was extracted using 0.1 M NaCl. Effect of proteinaceous extracts on amylase activity in both enzymatic assay and in gel assay using zymogram was performed. Results showed that the inhibitory process was dose dependant. The highest (17 mg protein) and the lowest concentration (1.0625 mg protein) of triticale extracts produced 70 and 30% inhibition activity, respectively. The highest inhibitory activity was observed at pH 8.Dose dependant manner of inhibition also was observed in gel assay. At the highest concentration of the inhibitor, two bands were completely eliminated while the intensity of major band was reduced.When the lowest dose was used two bands was removed but intensity of major band was still high.

Whiteflies are considered as citrus orchards pests in the north of Iran. The whitefly consumes large quantities of sap with its sucking mouthparts and weakens the plant. Further injury is caused by sooty mold fungus, Capnodium citri Berk. & Desm., which grows over fruit and foliage in the copious amount of honeydew excreted by the whitefly. This black fungus may cover the leaves and fruit so interferes with the proper physiological activities of the trees. In this investigation, biology and dynamics of the dominant species, citrus whitefly, Dialeurodes citri was studied in the west of Mazandaran province. Weekly sampling was done. Sampling of the adult stage was done with 4 leaves from 5 trees (20 samples). Sampling was taken of other stages of the pest including egg, nymph and puparium. The results indicated that adult insects of first generation emerged in late May. The peak of adult population was in mid June, early August and late September, respectively. Population density of the pest was high in citrus orchards, especially in nurseries and young citrus orchards. It was found that a complete life cycle took 50 days in summer. Depending on the conditions, the eggs hatching took 10-28 days. Nymphal stage took 21-32 days. The pupal stage was 10-14 days during summer.The pest overwinters as last nymphal stage and pupae under leaf underside. Citrus whitefly has three generations in a year.

Amaranth crop, Amaranthus cruentus L. (Amaranthaceae), can be used as forage crop. Recently, this crop has been studied in detail in Khuzestan province. During a study on agronomy characteristics of this crop in Ahvaz in summer 2011, widespread damage of a curculionid beetle was observed on the cultivated crop. The beetle was identified as Hypolixus pica Fabricius, 1798. This is the first report of an insect pest on the mentioned Amaranth crop in Iran. Here we report some damage symptoms of this curculionid pest on Amaranthus cruentus.