m. a. samih

The sweet potato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is an economically important pest of a variety of agricultural crops worldwide. The control of sweet potato whitefly largely relies on the use of synthetic insecticides. However, the efficiency of chemical control is questionable with respect to the activity of adults and immatures on the abaxial surfaces of leaves. In addition, under the strong selection pressure of the chemical control, whitefly populations have become resistant to most registered insecticides. Therefore, the search for more environmentally friendly options for whitefly control is necessary. Botanical extracts are broad-spectrum materials, used in pest control and they compared to synthetic ones may be safer for the environment, are, generally, less expensive and are often decomposed to nontoxic products. They are potentially suitable for use in integrated pest management. Recently, in addition to the botanical insecticides, vermicomposting has been also proposed as a safe control method for insect pests. Vermicompost is an organic soil amendment, produced by earthworm digestion of organic waste. Studies show that plants grown in soil amended with vermicompost grow faster, are more productive and are less susceptible to a number of arthropod pests. In this research studied the mortality effect of ethanol extracts of the seeds and leave of Ricinus communis L. (Euphorbiaceae), Sophora alopecuriodes L. (Fabaceae), Aloe vera (L.) (Liliaceae) on adults of B. tabaci that reared on a tomato that planting in vermicompost from two different sources (pistachio waste and cattle manure). This result was compared with the insecticide abamectin.

The experiments were carried out in a completely randomized design and in a growth chamber at 25±2 ºC, photoperiod of 16: 8 (L: D) and with the 55±5 % relative humidity. Seed from the tomato cultivar ‘CH-Falat’ were sown into the pots (5×10 cm), containing different growth media. The three growth mixtures tested were: (i) 100% BAGA (sterile plant growth media); (ii) 70% BAGA with 30% pistachio waste vermicompost; (iii) 70% BAGA with 30% cattle manure vermicompost. After the bushes reached the 2- 4 leaf stage the bioassay tests were done by using the leaf-dip method. After drying of leaves, 20 adults of B. tabaci (24h) were released into each pot. The mixture of ethanol and distilled water (1:10) was as a control. After 72 h, mortality was recorded. To determine the effects of the sub-lethal dose (LC25) on the developmental durations of B. tabaci, the tomato pots that were prepared as above mentioned, dipped into LC25 concentration of each extract and abamectin, for 5s. After the drying of leaves, 15 pairs of B. tabaci adults were released in the pots and the cage was covered on the pot immediately. B. tabaci were removed from the plants after 72 hours and only the eggs less than 24 hours old were kept for the recording of the different stages of B. tabaci.

Based on the results, the kind of growth media was effective in the influence of extracts and abamectin, and the least LC50 of each insecticide was recorded in growth media that was added by pistachio waste vermicompost. Among the extracts, Aloe vera and leave of R. communis extracts showed the best and lowest effect against the B. tabaci with LC 50 value of 0.855 g/l and 22.841 g/l respectively (in pistachio waste vermicompost media). Subletal (LC25) effects of treatments on biological parameters of B. tabaci were significant compared to the control plant (p<0.05). Based on the results, the most mortality (%) in egg (22.84%), nymphal (42.11%) and pupal (11.94%) periods of B. tabaci was recorded for abamectin, Aloe vera and S. alopecuriodes extracts respectively. The interaction between vermicompost and extract was significant, and the longest of the nymphal period (19.83±0.67 days) was recorded on whiteflies that were treated by R. communis and reared on tomato plants grown in pistachio waste vermicompost. The shortest of this period (11.14±0.34 days) was recorded on control plant that grown in BAGA. Taken together, the longest development time was recorded on whiteflies that treated by S. alopecuriodes and reared on tomato plants grown in pistachio waste vermicompost and the shortest of this period was on insects treated by Aloe vera extract and pistachio waste vermicompost media. Plants fertilized with pistachio waste vermicompost had significantly higher phenolic content (10 mg/mL) than control (BAGA) (6.08 mg/mL), while those in cattle manure vermicompost group exhibited intermediary value (7.28 mg/mL).

These results indicated that the concomitant use of extract and vermicompost was more effective for controlling of B. tabaci. The most mortality caused by Aloe vera extract and amending of pistachio waste vermicompost into growth media increased its effectiveness. So, these extract and vermicompost can play an important role in the managing of B. tabaci in greenhouse crops.

Nesidiocoris tenuis Reuter (Hemiptera: Miridae) is a zoophytophagous mirid known as a potential biological control agent of whiteflies and Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). This predator is widely used in integrated pest management programs in greenhouses. In this study, side effects of four pesticides including pymetrozin, abamectin chlorantraniliprole, mancozeb and iprodion carbendazim on survival and number of offspring N. tenuis were evaluated. Adults of predators exposed to the pesticides through residual and oral routes simultaneously. None of the pesticides except abamectin chlorantraniliprole cause significant mortality on predator but all of them were affected the number of offspring. The highest reduction in fertility was related to abamectin chlorantraniliprole (92.5%). Iprodion carbendazim (43.22%), pymetrozin (37.44%) and mancozeb (17.14%) were next in rank, respectively. Toxicity of pesticides was calculated based on the reduction coefficient, Ex. According to IOBC classification abamectin chlorantraniliprole was moderately harmful, pymetrozin and iprodion carbendazim were slightly harmful and mancozeb was harmless.

Characteristics such as lower developmental time, higher fertility and a large body size of natural enemies as biological control agents are important for mass rearing. Menochilus sexmaculatus (Fabricius) (Col.: Coccinellidae) is one of the major predators of pests in the orchards of Iran. The effect of six constant temperatures of 17.5, 20, 22.5, 25, 27.5 and 30 ºC were investigated on the development of the predator by feeding on the Pomegranate green aphid Aphis punicae (Hem.: Aphididae) under laboratory conditions (65 ± 5 RH and 16L: 8D h). The developmental time of M. sexmaculatus were 26.83± 0.61, 19.35 ± 0.23, 16.02 ±0.16, 11.66 ± 0.12, 10.45 ± 0.20 and 13.35 ± 0.33 days on above mentioned temperatures, respectively. The results showed that developmental time decreased with increasing temperature to 27.5 ºC. The lowest mortality was observed at 22.5ºC among the above-mentioned temperatures. The results indicated that there were significant differences for developmental times in different temperatures. Survival rate decreased away from the desirable temperature, 27.5 ºC, in both higher and lower orders. Lower temperature thresholds for eggs, larvae, pupae and adults were 10.69, 12.22, 12.83, 11.55ºC and thermal constants for egg, total larval period, pupa and egg to adult were 32.25, 83.33, 33.33, 166.66 degree-days, respectively, by feeding green pomegranate aphid. The results showed that optimum temperature were 25 to 27.5ºC for the rearing of the lady beetle.

The ladybird species Oenopia conglobata contaminata (Menetries) is one of the major predators of pests in the orchards across Iran. The life history and predation rate of this predator were studied under laboratory conditions with 27. 5 ± 2oC، 55 ± 5 RH and 16:8 h (L: D) photoperiod to 6-cm petri dishes. To study the demography، a cohort containing about 100 eggs with less than 24h of age was chosen. Ladybeetle larvae were fed daily on the immature stages of pomegranate green aphids، Aphis punicae Pass. The daily fertility، immature developmental time، mortality and predation rate data were analyzed using age-stage، two-sex life table analysis - MSChart software. Means and standard errors of population growth parameters were calculated by bootstrap method. To determine the predation rate، the first-instar beetle larvae were fed on the third and forth developmental stages of A. punicae. The adult ladybirds were grouped in pairs of opposite sexes to investigate their predation rates on daily basis. The intrinsic rate of increase (rm)، finite rate of increase (λ)، mean generation time (T0) and net reproductive rate)R0 (were 0. 181 d-1، 1. 198 d-1، 30. 58 d and 251. 65 offspring per individual respectively. Predation rate of different stages of forth-instar larvae and both adult sexes were 49. 56، 95 and 125، aphids respectively، and the average predation rate (C0) was 118 aphids that shows a high rate of predation on the aphid population.

Carob moth Ectomyelois ceratoniae Zell. (Lep.: Pyralidae) is the most important pest reducing the quality and the quantity of pomegranate trees products. Damage at the beginning of the spring causes shedding of the pomegranate flowers and fruits. In this study the effects of the gum extract of Ferula assa-foetida L. (Apiaceae) and natural sex pheromone of Carob moth was studied in 2010-2011 in the pomegranate orchard of Agricultural Research Center of Yazd. Three treatments including gum extract spray، natural sex pheromone traps and pheromone traps + gum extract (push-pull) were studied. In another experiment the effects of four concentrations of gum extract including 2، 3، 4 and 5 ml/l were studied on parasitism and mortality rate of Tricograma brasica (Hym. Trichogrammidae) at 25 ±20C، 55±5 RH and 16 h: 8 h L: D. All Experiments had control. The results showed that there were significant differences at 1% probability level between percent of pomegranates collected from under the trees، percent of pomegranates cracked due to carob moth damage and percent of cracked and rotten pomegranates in treatments studied. There were significant differences between percent of pomegranates cracked and the pomegranates cracked containing larvae at 5% probability level. The results showed that push pull treatment were more effective in reducing pest damage compared to the other methods. According to the results، use of gum extract in the push-pull strategy for controlling carob moth has no negative effect on parasitism activity of Trichogramma. Use of sex pheromones and gum extract decreased the carob moth population and it can reduce the control costs and the chemicals usage with attracting the pest to a predicted area

The common pistachio psylla, Agonoscena pistaciae Burckhardt and Lauterer (Hem.: Aphalaridae) is one of the most important pests of pistachio trees in Iran. Cultural methods such as crop fertilization can affect susceptibility of plants to insect pests attack by altering plant tissue nutrient levels. In this investigation we studied in relation to varying fertilization levels of Ca, U, Zn and amitraz on common pistachio psylla, A. pistaciae in pistachio orchards based on complete randomized blocks with six replications and nine treatments including applied Ca, U, Zn, Uzn, Uca, ZnCa, UZnCa, amitraz and control on common pistachio psylla fed on 20-year-old pistachio trees of Ahmadaghaei rootstock in Rafsanjan orchards. The results showed that the effect of nutrient solution on nymph and eggs population had a significant difference at %1 and 5% level, respectively. The highest measure of control on eggs was related to UZnCa while the least was related to ZnCa and amitraz. The results also showed that the highest measure of pest control was related to Ca while the least was related to amitraz and UZn. The results indicated that the elements mentioned had a stronger reducing effect on the concentration of common pistachio psylla nymphs than the effect pesticide had.

The Lady beetle، Hippodamia variegata is one of the natural enemies of Agonoscena pistaciae. Demographic toxicology is a common method for evaluating sublethal effects of insecticides on natural enemies. Regarding to use of hexaflumuron and spirodiclofen in pistachio gardens، present study conducted to evaluate the side effects of the pesticides on demographic parameters of H. variegata under controlled conditions (26 ±10C، 65±5% RH and 16:8h L: D). For this purpose، 120 fresh eggs were treated with field recommended concentration of insecticides and treated into Petri dishes 6 cm with distilled water was used as control، by dipping method. Results has shown that there were significant differences among treatment for gross reproductive rate (GRR)، net reproductive rates (R0)، intrinsic rate of increase (rm)، finite rate of increase (ג)، intrinsic birth rate (b) and doubling time (DT) parameters. The gross reproduction rates were estimated 24. 43±0. 38، 55. 67 ±0. 49 and 48. 11±0. 66 in hexaflumuron، spirodiclofen and control respectively. In addition، rm were estimated 0. 086±0. 0067، 0. 1086±0. 0045 and 0. 1232±0. 007، Moreover، DT values were recorded as 8. 62±0. 51، 6. 54±0. 25 and 5. 88±0. 29 as above mentioned، respectively. According to this experiments، hexaflumuron had higher negative effect on intrinsic rate of H. variegata and it will be suggested that to be considered in integrated pest management.