Applied Entomology and Phytopathology
Year:2001 | Volume:69 | Issue:1|Papers Count:16

Status of wheat seed gall nematode (Anguina tritici) was studied in irrigated wheat fields of Esfahan province .during 1994-97. For this purpose, 152 samples were taken from different parts of Esfahan. In the surveyed regions, 21.71% of fields were infested with the nematode in Ardestan, . Esfahan, Lenjan, Semirom, Shahreza, Fereydan, Fereydonshahr, Kashan, Mobarekeh, Najafabad and Natanz regions.The mean of infected heads was 5.82% and crop loss estimated to be 0.3% of the total yeilds (1444 tons of wheat). The various ranges in size of the nematode galls and the population of A.tritice 12 in collected wheat samples were determined in each area.The vaious ranges of the nematode galls were measured 2.4-5.3 x1.5-4.2mm .The maxium and minimum of second stagejuvenile (J2)in the nematod galls were culculated as 40250 and 4625 respectively. The loss of A.tritici on wheat, Roshan variety under field conditions with 4 treatments. 0.1.2 and 4% infested with galls were calculated as 0.10.68 . 21.13 and 34.93% respectively.

Cereal stem moth Ochsenheimeria vacculella is a small, relatively slender moths which is univoltine and diurnal. Wing expanse: 11-14 mm., vertex extremly rough densely covered with long, divergent, stramineous scales. Compound eyes rounded, relatively small, a pair of rather large ocelli present near to antennal sockets, antennae simple and short. The common colour of body and forewings is fuscous, dorsum of sixth abdominal segment is pale yellow which is characterisitic for the pest. The moth overwinters as egg in wall cracks. After emerging in spring, the first instar larvae blown away to the host plants by the wind. Larvae are white- yellow, with black head. pronotum and last abdominal segment with two dark-brown areas. Chrochetes reduced in numbers. maximum length of mature larvae is 18- 20mm. First instar larvae feed on leaves and older ones bore in to the stems. The most damage is caused by the larvae which gnaw below or directly into the ears. causing "white ears". Pupation occurs among cereal leaves and the stems at the late of May. Adults emerge during the first fort night of June.The highest damage was recorded in Zaghmar village. where %6.85 of the ears were dried up completely and %7.5 was fed directly by the pest.

Biology of carmine spider mite (Tetranychus cinnabarinus) has been studied on difterent ornamental host plants (Rose, Ficus, Gerbera, Gladiolus, and Dieffenbachia) under laboratory conditions (20±2, 26±2, 30±2°C,30-60% R. H. and 16 Land 8 D), during 1998- 1999. Both sexes of mite have three developmental stages (larva, protonymph and deutonymph) and interrupted with a quiescent stage in between. Min. and Max. duration of immature stages for male and female recorded 1I.01±0.67,28.33±1.2and 11.42± 0.48, 33.25±1.88days under 30±2 and 20 ±2°C on rose and ficus respectively. Analysis of collected data indicated that, a negative correlation between in an increase of temperature and reduction in mite developmental stages and in female longevity also observed. Under field condition of Varamin region the female mite entered in diapause when temperature fall below mean of 15°C. Effect of different laboratory temperatures on diapause of female mite were studied. A negative correlation observed when diapause interrupted by an increase of temperature. but statistically was not signigicent at the rate of oviposition.

To investigate cold hardiness of Eurygaster integriceps put., the supercooling pomt of whole bodies during August to April 1998-1999 and 1999-2000 were measured on samples collected from altitude of Ateshgah karaj-Iran. The supercooling point during summer was lowest, being about -17°C. and in early winter of 1998-99 and 1999-2000 were -12.9°C and -6.7°C respectively. Considering to minimum temperature in natural condition (-12.5°C and -13°C in January 1999 and 2000, respectively), insect use dual strategy for cold hardiness. Furthermore. supercooling points of different sex. weight, size and altitudes were not significantly difJerent. However, \vet individuals exhibit significantly higher supercooling points than dry ones.

Development of simulation model is very suitable to understand insects systems. It offers a possibility to recognize possible gaps in our knowledge. A simulation model of immature stages development of greenhouse whitefly Trialeurodes vaporariorum (Westwood) population is presented. The parameters, variables, selection of data used for the model and the formulation of equations are discussed. A network form and a program listing are provided with technical details on modeling with SLAM II software. To validate model there were two data sets available to compare the model result with. The data came from an experiment that was carried out in greenhouse condition. In this experiment there were followed and recorded the numbers of developmental stages of two sets of 106 and 115 whitefly eggs on tomato leaves daily. The simulations provide data that are corresponding well with experimental data collected in greenhouse. Total of all immature duration from 106 eggs took 56 days in model and 52 days in observation. Total of all immature duration from 115 eggs took 58 days in model and 52 days in observation.

In this study disease samples from mushroom farms were collected and several species of Trichoderma were identified include, Trichoderma harzianum Rifai, T. longibrachiatum Rifai , T. virens (Miller, Giddens & Foster) and Trichoderma sp. Results of the growth patterns in 25°C showed significant differences in the type of growth and sporulation patterns between different species and isolates.Each isolate had several growth patterns. However regarding to distribution and relative abundance. each species showed different patterns in the surveyed mushroom farms. Fortunately, most of the pathogenic species were observed in all of the samples include pasteurized and non pasteurized compost, Casing layer and mushroom beds too. Besides in this study. we have also determined growth patterns and growth curves and also veryfied these effects on growth patterns as well as their morphological characteristics.

P. alhageos reported as a vine pest trom Iran since long time ago Nymphs damage the host plant by feeding on roots and adults by laying their eggs under the bark of the shoots and teeding on newly formed buds. This study showed that the cicada complete its lite cycle in four years via five nymphal instars, each female lay 600-900 eggs under the bark of young shoots in two rows. Thedurationof embryonicstage,1st, 2nd, 3rd,4th and 5th nymphal stages are 1, 4, 12, 12, 12 and 8 months respectivly.The longevity of the adults is almost 2 weeks. To investigate the insects biology it was reared in cages instuled in vine yards under nataral conditions. The studies showed that appropriate cultural practices considerably reduce the pests damage and with out further application chemical control.

The effects of tenitrothion and deltamethrin on preimaginal stages. emergence and life table parameters of sunn pest egg parasitoid Trissolcus semistriatus were investigated. These insecticides are applied to control sunn pest Eurygaster integriceps in Iran, Parasitized host eggs in the preimaginal stages (2, 4, 6 and 8 days after parasitism) were exposed to field recommended dose of the insecticides. Although both insecticides affected the emergence of the adult parasitoids from the host eggs significantly, the development of preimaginal stages were not affected, suggesting that sunn pest egg shell acted as an efficient barrier to insecticide penetration. However, parasitoids apparently came in contact with the insecticide residues while chewing through the host egg shells to emerge. Deltamethrin significantly reduced emergence rate in all preimaginal stages but fenitrothion had a reduction in emergencerate on days 6th and 8th after parasitism.Progeny production of emergent females was signiticantly reduced by deltamethrin but not by fenitrothion. None of the tested insecticides affected longevity significantly. The sex ratio of the progeny was atTectedby both insecticides and was male-based. The intrinsic rate of increase for control, fenitrothion and deltamethrin were 0.297, 0.280 and 0.269 female offspring per female per day respectively.

An investigation was carried out to detennine the suitable time for chemical control of four spotted bean weevil in 1994-1995 in Karaj region.The cowpea variety 29005 was used in a randomized complete block design with 4 treatments and 4 replications. The treatments were three spraying dates, the first spray (A) has been done at the appearance of pods. The second (B) and the third (C) at an interval of 10 daysfrom the first spray. The fourth (D) was checked (without spraying). Eterimphos 50% was used for spraying in all of the treatments (except check plots) at the rate of 2 litres per hectar.In three times sampling, 150 pods were chosed from each replication to detennine the percentage of infestation. The data obtained at the end of the second year of study and were analyzed with combined variation analysis method.The analysis of variance revealed that, there was a significant difference between the treatments. Treatment (A) with 12.33% contamination and (B) with 11.14% were the least contaminated treatments in comparison with the others. Therefore, one spraying of cowpea at the time of appearance the pods until 10 days later was the most suitable to control four-spotted cowpea.

Fourteen species of whiteflies (Homoptera: Aleyrodidae: Aleyrodinae) including Trialeurodes vaporariorum on Altheae sp., Lantana camara, Cestrum nocturum and Euphorbia pulcherrima; Bemisia tabaci and Bemisia argentifolii on Altheae sp., L. camara and Absena velvetleaf; Bemisia hancoki on A. velvetleaf and Medicago sativa; Aleyrodes proletella (=Aleyrodes brassicae) on brassica sp., Aleyrodes rosae on Rosa sp. Bulgarialeurodes cotesii on E. pulcherrima; Aleyrodes singularis and Trialeurodes packardi on Punica granatum; Trialeurodes ricini on C .nocturum and Rosa sp ;.Aleurolobus moundi and Aleurolobus selangorensis on Citrus aurantium; Siphoninus phillyreae on Ulmus carpinifolia. and Acaudaleyrodes citri on C. aurantium were collected and identified. All species from Isfahan and two species, A. proletella and B. argentifolii are the first record from Iran. The identification key and description of subfamilies, tribes, genera and species upon the characteristics of pupal and for the new record from Iran upon the adult stages and the synonyms of the identified species were prepared.

Sexual attracting in several species of tephritid fruit flies involves chemical, visual and auditory stimuli or combinations of these stimuli. In this research the effect of chemical cues in sexual attraction of Bacterocera ciliatus Loew has been studied via the active and passive bioassay methods. The results have shown that males attracted females in both methods. Daily rhythm and age at appearance of attraction in this species coincides with mating in natural conditions, which indicates that these two parameters are associated with sexual attraction. Sexual attraction seems to be regulated by light intensity and reaches maximum levels during the last hour of the photophase. In this species sexual attraction reaches maximum at the age of 8-15 days old and will be decrease in other ages.