نشریه تحقیقات نوین در گیاه پزشکی
سال ششم شماره 3 (پیاپی 17، پاییز 1393)

Sitobion avenae (F.) is an important species infesting wheat spikes in region Dehloran, Iran. To evaluate the spatial distribution of O. avenae on wheat, weekly samplings were carried out from five winter wheat fields around Dehloran throughout 2010-2011. Spatial distribution of different developmental stages and morphs of the aphid were described by fitting data to Poisson (random) and negative binomial (clumped) distributions. Based on R2 and F of regression analysis, Taylor’s power law provided a more adequate description of variance/mean relationships than Iwao’s patchiness regression model, and the b values ranged from 1.102 (alate adults) to 1.463 (apterous adults). Other distribution indexes and spatial distribution models showed the cumulative distribution of aphid population on clusters and fitting to negative binominal distribution in many section of season. Mature winged aphids were more likely to show a random distribution compared to other developmental stages.

Fig spider mite, Eotetranychus hirsti (Acari: Tetranychidae) is a serious pest of figs (Ficus carica L.) in Iran and other fig growing areas in the world. Under low mite infestation level, the leaves show small transparent patches while under high infestation the leaves with yellowish-green appearance drop down prematurely. Effects of three doses (0.3, 0.4, 0.5 per thousand liters) of new acaricide envidor speed (spirodiclofen 222+abamactin, 18g/l SC) evaluated in comparison with three other acaricides i.e. spirodiclifen (0.5 per thousand liters), bromopropylate (1.5 per thousand liters) and abamectin (0.5 per thousand liters) on egg and adult stages of fig spider on Ezmir variety of fig orchards in Agricultural Research Center (ARC) of Estahban-Fars, during 2014. Five replications for every treatment done through randomized complete block design. 50 leaves were plucked from each block at random and number of egg and adult of Eo. hirsti recorded through ten sampling interval, one day before, 1, 3, 5, 7, 10, 15, 20, 24 and 30 days after chemical applications. The efficacy of the acaricides was calculated by Henderson and Tilton formula. The data were subjected to ANOVA and the means were analyzed by Duncan test. The results showed that after 5 days, three dose of envidor speed have a good effect than bromopropylate and abamectin. While the treated trees with bromopropylate and abamectin have a significant population of egg mite 16.6 and 22.5 eggs respectively, after 30 days. The mean number of eggs in treated trees with bromopropylate and abamectin increased after 15 days. Efficacy of bromopropylate and abamectin showed an absolute control on adult mite after one day and mean mortality was 93.12 and 98.12 percent, respectively. Different concentration of envidor speed showed high efficacy after 3 days and for 03, 0.4 and 0.5 mortality were 94.99, 94.65 and 100%, respectively. Spirodiclofen showed high efficacy after 7 days. The efficacy of bromopropylate and abamectin decreased after 15 days and were 47.13 and 72.43% after 30 days, respectively. The results showed that envidor speed has a longer and good effect on egg and adult form of fig spider mite.

Rose flowers are as a shrubs plants which have several pests including rose aphid, Macrosiphum rosae. Aphids control more dependent on the use of chemical insecticides. Due to the frequent use of pesticides, many species of aphids have become resistant to many chemicals. So, the alternative method is needed to control aphids. In this study, in order to reduce pest damage and adverse effects of pesticides, the effects of Azadirachtin indicae on reproductive parameters of rose aphid were studied. Experiments were conducted in the laboratory condition, temperature 25 ± 1ºC, 60±5 % RH and photoperiod 16: 8 (L: D). After bioassay, the amount of LC10, LC25, LC50 and LC90 azadirachtin on rose aphid were calculated 0.5, 0.9, 1.62 and 4.94 ml/l, respectively. The data of fertility life table and reproductive parameters of rose aphid obtained on these concentrations. Maximum longevity of rose aphid was in the control and the minimums were in the 0.9 and 1.62 ml/l of the concentrations. Life expectancy in the first day of aphid, in control and 0.5, 0.9, 1.62 and 4.94 ml/l of azadirachtin concentrations was 9.85, 4.5, 3.22, 2.37 and 0. 95 days, respectively. The gross reproduction rate (GRR) of rose aphid in the control and 0.5, 0.9 and 1.62 ml/l of azadirachtin concentrations were 19.13, 8.73, 4.19 and 3.66 nymphs/female, respectively. The net reproductive rate (R0) with mortality of reproductive female, in the control and 0.5, 0.9 and 1.62 ml/l of azadirachtin concentrations was 12.95, 3.1, 1.3 and 1.02 nymphs, respectively. The intrinsic rate of natural increase (rm) in the control and 0.5, 0.9 and 1.62 ml/l of azadirachtin was 0.30, 0.18, 0.04, and 0.01 day-1, respectively. The results indicated a strong effect of azadirachtin on reproductive parameters of rese aphid.

Bemesia tabaci is an important pests in tomato fields. Effect of some control methods for these insect was evaluated in tomato nursery. This experiment was conducted in Borazjan, Bushehr Agricultural and Natural Resource Research Center. The treatments consisted of; yellow sticky trap, aluminum mulch on soil, cloth net mulch on plots, oil (1%) and pesticide (Imidaclopride 0.8 ml/l) spray and control (without any control method). These treatments were laid in a RCBD (Randomized Block Design) with 3 replications. Number of whitefly nymphs on 15 leaflets was recorded. The treatments were compared with Duncan`s Multiple Range Test. The results indicated that cloth net mulch has the lowest number of whitefly nymph. All treatments were coefficient different with control.

The use of botanical insecticide instead of chemical insecticide is one way to preserving the enviroment. In this research, the effect of three concentrations of the botanical insecticide, Tondexir (pepper extract), on two natural enemies of the pistachio psyllid, the first and fourth instar larvae and adult of the Coccinellid Predator Oenopia conglobata. (Coleoptera: Coccinellidae), and the pupa and adult of the Parasitic Wasp Psyllaephagus pistaciae (Hymenoptera: Encyrtidae) were investigated. A topical bioassay was used in laboratory conditions. Two field experiments were conducted with Tondexir and acetamiprid on mummy pupae of Parasitoeid in completely randomized block design in 2010 and 2011 In Rafsanjan, Iran. On chemical insecticide, acetamiprid, have been used in comparison with Tondexir. The results showed that Tondexir is less effective than acetamiprid on two natural enemies of Pistachio psyllid. Consistent with the IOBC, Tondexir was categorized as being harmless on first instar larvae, harmless on fourth instar larvae, harmless on adult Predator and slightly harmful on adult PW. Acetamiprid was categorized as moderately harmful, slightly harmful and slightly harmful on the above stages of two insects. The result of fieldexperiments showed that two insecticides were categorized as harmless onmummy of Parasitoid. Overall, the results have shown that Tondexir has lesseffect than chemical insecticides on two natural enemies and can be used inpistachio orchards.

Fusarium solani the causal agent of Fusarium dry rot of potato has a wide host range and worldwide distribution. Trichoderma is the most commonly used fungal biological control agent and have long been known as effective antagonists against plant pathogenic fungi. In present study volatile and non-volatile compounds produced from seven isolates of Trichoderma species including T. harzianum (1, 2, 3 and 4), T. virens, T. koningii and T. longibrachiatum were avaluated for their antagonistic effects in vitro against F. solani. The volatile compounds produced form all antagonistic isolates showed mycelial inhibition of the test fungi. T. longibrachiatum and T. harzianum 3 revealed the highest and the lowest antibiosis activity against mycelial growth, respectively. Investigating the effect of non-volatile compounds at 5 and 10 ml concentration showed that the highest inhibitory percentage on mycelium growth of the pathogen caused by T. harzianum 1 (14.28%) and T. harzianum 2 (9.76%) respectively.

Cucumber wilt disease caused by Fusarium oxysporum f.sp. cucumerinum is one of the most important diseases of cucumber. Disease severity can be decreased by plant nutrition management, especially nitrogen level. In this study, the effects of nitrogen sources such as KNO3 and NH4NO3 on the growth of fungus (Fusarium oxysporum f. sp. cucumerinum) on PDA medium and interaction between plant nutrition (N) and cucumber Fusarium wilt disease on some cultivar of cucumber in greenhouse hydroponic culture were investigated. The effects of nitrogen sources such as KNO3 and NH4NO3 were investigated on growth area of F.oxysporum f. sp. cucumerinum on PDA medium by a completely randomized design with 4 replications. Variance analysis of growth area of the fungus showed significant effect on the different factors used in this experiment. The highest area growth of fungus was obtained at 0.1 g/l for KNO3. Ammonium nitrate (NH4NO3) significantly reduced the mycelial growth compared to the control treatment. Effects of different N levels were investigated on two greenhouse cucumber cultivars (exterem and soltan) at the presence of fungus (F. oxysporum f. sp. cucumerinum). A completely randomized design with 4 replications was used for this experiment. The results showed that increasing of nitrogen level (20 meq/l NO3-) compared to the control treatment (distilled water + fungus) decrease the disease severity. The results showed that cucumber nutrition with nitrogen affects the F. oxysporum f. sp. cucumerinum. Also the importance of plant nutrituin management for decrease of disease severity was shown.