نشریه تحقیقات نوین در گیاه پزشکی
پیاپی 4 (زمستان 1388)

To evaluate Diazinon residue in greenhouse cucumber in fruit and vegetable marketsin Tehrans, 90 samples were conducted from 59 area selected by stratified samplingmethod. First the samples divided by two groups, washed samples and not washedsamples, then each of them divided by three types peeled, not peeled and only peelings.The residues measured in all of the type samples extracted by solid phase extractionmethod and extracts analyzed by GC and GC/MS systems. Results showed that in twosamples there were residue higher than the Maximum Residual Levels, and the amountof residue were 1.2 ppm in washed and notpeeled sample (washed cucumber) and 10.4ppm in not washed peel sample.

Camelthorn is a perennial noxious weed belonging to the Fabaceae family that existalmost in the most regions in Iran and reproduces by seed and rhizome. In 2008, a seedbeetle was collected on legumes of camelthorn which identified as Bruchidius fulvus(Allard, 1883). Biology of this insect was studied in laboratory conditions in15±1:25±1˚C light:day, relative humidity of 65±5% and length of light: dark 12:12h andalso field (Natural) conditions. Incubation period of eggs prolonged about 6±1.71 days.Eggs placed on legumes individually and the mean number of egg lay for a female was19.8±0.95 eggs. The larva bore directly into the seeds through the cortex at the end ofembryonic development. The mature larvae change to the pupa inside the seed. Thisbeetle has 2-3 generations annually in Birjand and overwinters as larva inside extantlegumes of host plant. The larvae change to pupa and adult in late spring and earlysummer (beginning of flowering camelthorn). The adult females start to lay eggs afterhaving a taste from host leaves and flowers, simultaneous by appearing legumes. Only alarva remains inside each seed and grow after feeding from inner parts of the legumes andchange to pupa there. Adult seed beetles make their way outside by boring a small holeon the seed and extant legume. The life cycle accomplishment of this beetle from egg toadult depends on environmental condition lasted 48.8±2.48 days. Under laboratoryconditions, larval and pupal periods last about 32±0.94 and 11±0.54 days, respectively.The larvae of this beetle can damage camelthorn seeds up to 35-48% in naturalconditions. Because of its impact on seed production, the camelthorn weevil may be avaluable candidate for biological control of camelthorn in the south khorasan.

Wild amaranth, Amaranthus retroflexus L. is one of the dominant summer weeds ofcitrus orchards in Dezful. Adults and larvae of snout beetle, Hypolixus pica (F.) feed onthis weed and decrease its growth and reproduction. Population dynamics of H. pica wasstudied during the growing period of wild amaranth in a citrus orchard in Dezful. Everytwo weeks 30 plants (replications) were sampled and developmental stages of weevilwere counted. The population of eggs started at the beginning of May and peaked in mid- July (23 eggs in 30 plants). In early November no eggs were observed. The population of larvae started in mid- May, increased gradually and peaked at the beginning of November (103 larvae in 30 plants). Pupae population started in mid-July and peaked in mid- September (24 pupae in 30 plants). Peak of adult female population was observed in the mid-September while adult male population had two peaks in early October andNovember. The population of parasitoids started at the beginning of June. The lowest and the peak number of parasitoids occured in early May and mid-August, respectively. The parasitoids Habrobracon hebetor, Eurytoma curculionum and Cyrtoptx sp. had feedingactivity on larvae.

Cotton plant, Gossypium hirsutum L., is one of the most economic crop around theworld and in GonbadKavous (located in North of Iran) is an important cotton croppingregion. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damagingpests on the field crops. Use of resistant cultivar is one of the foremost acceptedchemical-free techniques for controlling this pest. A two year study was conducted toevaluate resistance of two most-cultivated cultivars, sahel and siokra, against spidermites. The results showed that there was a significant difference in population of spidermites, so that the population on Sahel was more than Siokra for two years studied. Theseparate population figures for each year recorded 10.3 ± 0.6 eggs and 24.2 ± 1.3 miteson Sahel, 7.4 ± 0.4 eggs and 15.9 ± 0.9 mites on Siokra in first year whereas it was 22.6 2.1 eggs and 35.2 ± 2.6 mites and also 8.6 ± 0.5 eggs and 16.9 ± 1.1 mites in second year for them. Mite’s populations increased from mid-season to the end of growing period. The results showed that effects of ambient temperatures on egg populations and number of active stages of mites was more favorable on Sahel compared with Siokra. Population assessment of mites on these two cultivars can be used in management of the pest.

In this research the effect of Bacillus thuringiensis, Carbaryl and Diflubenzuronindependently and different combinations of them were tested against Helithis viriplacaHuFn. in laboratory conditions. In order to conduct bioassay experiments, the pupa werecollected from the field and reared under controlled conditions. Third larval stage wasused for bioassay experiments. In bioassay experiments the best concentration ofcompounds were selected individually and in combination using randomized blockdesign. The laboratory tests showed that Bt with concentration of 2600 ppm and 1900ppm revealed the best result and Carbaryl with concentration of 1900 ppm and Bt withconcentration 1600 ppm were in the second rank. The comparison of tested compoundsindividually and in combination showed that mixture of Carbaryl-Diflubenzuron-Bt,Carbaryl-Bt, and Diflubenzuron-Bt were better than other treatments (p≤ 0.01) andCrarbaryl and Diflubenzuron mixture had least effect with no statistical difference withBt effect.

Beauvaria bassiana (Buls.) Vuill. is one of the Sawtoothed beetle, Oryzaephilussurinamensis (L.), pathogens in date stored condition. The ability of differentdevelopmental stages of the beetle to disperse the fungus primary inoculums in three date cultivars Sayer, Zahedi and Deiri were studied. The individual dispersal functions asspore dispersal power and cross infestation rate as spore dispersal rate were calculated.Results showed that there were significant differences in spore dispersal ability by larvaland adult stages and in three studied date cultivars. The slope of individual dispersalfunctions for different developmental stages were negative that indicating the reduction of primary inoculums of pathogen by distance. The rate of primary inoculums transmissionwas reduced by time also. So, the maximum of dispersal occurred in first days ofinoculation. Maximum spore dispersal occurred on Deiri and its amount was similar inSayer and Zahedi. The adults were more effective on dispersal of primary inoculums ondate than the larvae. Conidial dispersion on date wasnt aggressive and the fungi conidiawere dispersed on all sites of stored date. Dispersal rate by adults was faster than larvae.

Deroceras agreste (L.) is a pest of lettuce in different regions of Iran and world. Theirdamage is feeding from leaves, stems, roots and seeds.The aim of this study was todetermine the effectiveness of iron phosphate in comparison with registeredmolluscicides against D.agreste in lettuce fields of Mazandaran and Tehran provincesduring 2007-2008. The field studies were conducted according on randomized completeblock design method with four treatments and four replications. Treatments were ironphosphate baits (pellets 1%) at dose 5 gr/m², metaldehyde bait (2.5 gr/ m²), carbaryl bait (3 gr/ m²) and control. The percent of slug mortalities in all treatments were foundsignificant at α=5% (p<0.05). iron phosphate applied (5 gr/ m²) caused 65.40 % mortality and that of metaldehyde (2.5 gr./ m²) and carbaryl (3 gr./ m²) were 74.93% and 71.61% respectively. In Sari, Mortality percentage of iron phosphate (5gr/m²) was singnificantly higher. control (71.26%) as compared with metaldehyde (70.42%) and carbaryl (68.06%) treatments. Application of 5gr/m² Iron phosphate and 2.5gr/ m² metaldehyde and 3gr/ m² carbaryl were placed in group of A, B and C respectively, by Duncan test. It was proved that mortality of slugs increased as time passed regardless of doses (Iron phosphate) and was found max. in day 14 of sampling. Percent mean of slug mortality in Sari region was higher (69.91%) compared with that of observed Varamin (71.38%) regions. In total, results of present study indicated that, Iron phosphate 5 gr/m², due to possessing the least environmental pollution, among the registered molluscicides and because of its higher efficacy in wet condition can be recommended against D. agreste in lettuce fields of Iran.

One of the most important pathogen attacking pigeonpea root, the nematodeHeterodera cajani Koshy, is causing significant economic losses in India. Knowledge ofgenetic variability present among different geographical populations is important for theselection of suitable control strategies. Molecular diversity among ten populations of H.cajani in India from pigeonpea growing areas is demonstrated by random amplifiedpolymorphic DNA (RAPD). Operon series of decamer primers were used for exploringthe polymorphism. The number of amplified fragments per primer varied from 7 (withOPA 16 and OPD 4) to 24 (with OPB 2) whereas the size varied from 300 bp to 3.1 kb.Out of the 32 primers tested 23 revealed 100% polymorphism (OPA 1, 2, 3, 4, 5, 6, 10,OPB 2, 3, 4, 12, OPC 1, 4, 5, 7, 8, 9, 10, 11, 16, OPD 4 and 10). Overall, 451amplification products were obtained out of which, 434 were polymorphic and 17 weremonomorphic. The Jaccard’s coefficient and cluster analysis showed that the nematodepopulation from Indore was distinct from the other populations of H. cajani in India.Samastipur and Pusa R.S. populations showed high degree of similarity in thisexperiment.