PLANT PROTECTION JOURNAL
Year:2009 | Volume:1 | Issue:4|Papers Count:9

To evaluate Diazinon residue in greenhouse cucumber in fruit and vegetable markets in Tehrans, 90 samples were conducted from 59 area selected by stratified sampling method. First the samples divided by two groups ,washed samples and not washed samples , 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 extraction method and extracts analyzed by GC and GC/MS systems. Results showed that in two samples there were residue higher than the Maximum Residual Levels , and the amount of residue were 1.2 ppm in washed and notpeeled sample (washed cucumber) and 10.4 ppm in not washed peel sample.

Camelthorn is a perennial noxious weed belonging to the Fabaceae family that exist almost in the most regions in Iran and reproduces by seed and rhizome. In 2008, a seed beetle was collected on legumes of camelthorn which identified as Bruchidius fulvus (Allard, 1883). Biology of this insect was studied in laboratory conditions in 15±1:25±1˚C light:day, relative humidity of 65±5% and length of light: dark 12:12h and also 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 was 19.8±0.95 eggs. The larva bore directly into the seeds through the cortex at the end of embryonic development. The mature larvae change to the pupa inside the seed. This beetle has 2-3 generations annually in Birjand and overwinters as larva inside extant legumes of host plant. The larvae change to pupa and adult in late spring and early summer (beginning of flowering camelthorn). The adult females start to lay eggs after having a taste from host leaves and flowers, simultaneous by appearing legumes. Only a larva remains inside each seed and grow after feeding from inner parts of the legumes and change to pupa there. Adult seed beetles make their way outside by boring a small hole on the seed and extant legume. The life cycle accomplishment of this beetle from egg to adult depends on environmental condition lasted 48.8±2.48 days. Under laboratory conditions, 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 natural conditions. Because of its impact on seed production, the camelthorn weevil may be a valuable candidate for biological control of camelthorn in the south khorasan.

Wild amaranth, Amaranthus retroflexus L. is one of the dominant summer weeds of citrus orchards in Dezful. Adults and larvae of snout beetle, Hypolixus pica (F.) feed on this weed and decrease its growth and reproduction. Population dynamics of H. pica was studied during the growing period of wild amaranth in a citrus orchard in Dezful. Every two weeks 30 plants (replications) were sampled and developmental stages of weevil were 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 and November. 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 feeding activity on larvae.

Cotton plant, Gossypium hirsutum L., is one of the most economic crop around the world and in GonbadKavous (located in North of Iran) is an important cotton cropping region. The spider mites (Tetranychus spp., Acari: Tetranychidae) are the most damaging pests on the field crops. Use of resistant cultivar is one of the foremost accepted chemical-free techniques for controlling this pest. A two year study was conducted to evaluate resistance of two most-cultivated cultivars, sahel and siokra, against spider mites. The results showed that there was a significant difference in population of spider mites, so that the population on Sahel was more than Siokra for two years studied. The separate population figures for each year recorded 10.3 ± 0.6 eggs and 24.2 ± 1.3 mites on 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 Diflubenzuron independently and different combinations of them were tested against Helithis viriplaca HuFn. in laboratory conditions. In order to conduct bioassay experiments, the pupa were collected from the field and reared under controlled conditions. Third larval stage was used for bioassay experiments. In bioassay experiments the best concentration of compounds were selected individually and in combination using randomized block design. The laboratory tests showed that  Bt with concentration of 2600 ppm and 1900 ppm revealed the best result and Carbaryl with concentration of 1900 ppm and Bt with concentration 1600 ppm were in the second rank. The comparison of tested compounds individually and in combination showed that mixture of Carbaryl-Diflubenzuron-Bt, Carbaryl-Bt, and Diflubenzuron-Bt were better than other treatments (p≤ 0.01) and Crarbaryl and Diflubenzuron mixture had least effect with no statistical difference with Bt effect.

Beauvaria bassiana (Buls.) Vuill. is one of the Sawtoothed beetle, Oryzaephilus surinamensis (L.), pathogens in date stored condition. The ability of different developmental stages of the beetle to disperse the fungus primary inoculums in three date cultivars Sayer, Zahedi and Deiri were studied. The individual dispersal functions as spore dispersal power and cross infestation rate as spore dispersal rate were calculated. Results showed that there were significant differences in spore dispersal ability by larval and adult stages and in three studied date cultivars. The slope of individual dispersal functions for different developmental stages were negative that indicating the reduction of primary inoculums of pathogen by distance. The rate of primary inoculums transmission was reduced by time also. So, the maximum of dispersal occurred in first days of inoculation. Maximum spore dispersal occurred on Deiri and its amount was similar in Sayer and Zahedi. The adults were more effective on dispersal of primary inoculums on date than the larvae. Conidial dispersion on date wasn't aggressive and the fungi conidia were 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. Their damage is feeding from leaves, stems, roots and seeds.The aim of this study was to determine the effectiveness of iron phosphate in comparison with registered molluscicides against D.agreste in lettuce fields of Mazandaran and Tehran provinces during 2007-2008. The field studies were conducted according on randomized complete block design method with four treatments and four replications. Treatments were iron phosphate 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 found significant 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 nematode Heterodera cajani Koshy, is causing significant economic losses in India. Knowledge of genetic variability present among different geographical populations is important for the selection of suitable control strategies. Molecular diversity among ten populations of H. cajani in India from pigeonpea growing areas is demonstrated by random amplified polymorphic DNA (RAPD). Operon series of decamer primers were used for exploring the polymorphism. The number of amplified fragments per primer varied from 7 (with OPA 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, 451 amplification products were obtained out of which, 434 were polymorphic and 17 were monomorphic. The Jaccard’s coefficient and cluster analysis showed that the nematode population 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 this experiment.