فصلنامه تحقیقات آفات گیاهی
سال نهم شماره 3 (پاییز 1398)

The use of insect cell lines for producing bio-pesticides, recombinant protein expression or gene delivery is increasing. Hence, the establishment of new cell lines will help to enrich this technology. Therefore, the purpose of this research is preparation of several primary cultures initiated from hemocytes of Helicoverpa armigera (Hubner),Anagasta kuehniella (Zeller) and Arge ochropus (Gmelin). The cultures were incubated in EX-cell 400 medium supplemented with 0, 5, 10, 15 and 20% concentrations of fetal bovine serum (FBS) at 28ºC. The concentrations of FBS were chosen on the basis of previous research. Results showed no growth in any of the cell lines when FBS was omitted from the medium. Maximal growth of H. armigerahemocytes was obtained with 15% FBS. There was no further increase in growth as FBS concentration was increased to 20%, Maximal growth of A. kuehniella hemocytes was obtained at 10% FBS. The growth of these cells was significantly lower at 15 and 20% FBS. As the fetal bovine serum concentration increased, A. ochropus hemocytes growth increased.  In conclusion, the current investigation demonstrated the lowest concentration of FBS required for maximal growth of insect cells in vitro.

The common pistachio psylla, Agonoscena pistaciae is the most important pest of pistachio trees which causes serious damage to pistachio crops. In the present study, we investigated some physiological-biochemical responses of pistachio Akbari cultivar at different feeding periods (2 to 192 h). Hydrogen peroxide contents as stress index had no significant differences between treatments (except for 2 and 96 h treatments). Also a significant decrease was gained in activities of superoxide dismutase (SOD) and catalase (CAT). The lowest activity of SOD, CAT and ascorbate peroxidase (APX) observed at 144 and 192 h. The amount of total protein increased significantly in response to the pest feeding and the lowest concentration observed at the onset of experiment. Total phenolic content increased following psylla feeding while no significant changes observed in total soluble carbohydrates. Amount of the pigments fluctuated in different times of feeding and their elevation after 144 h indicated optimal plant growth under stress conditions. The highest amounts of carotenoids, total phenolic content and total protein after 144 h were associated with the lowest activities of defensive enzymes. Our results showed an appropriate combination of enzymatic and non-enzymatic antioxidants leads to plant conservation and homeostasis regulation under stress conditions.

The use of herbal extracts as natural compounds in pest control is one of the most promising prospects for reducing future chemical pesticide use. The present study was conducted to evaluate in vitro effects of Golder and Myrtle extracts and also interaction between obtained different levels of concentrations for controlling Bemisia tabaci, on tomato under laboratory conditions. Plant extracts were used at 5 levels plus control. The effects of plant extracts and their interactions on B. tabaci, as well as lethal concentrations were determined. Concentrations of 0, 2, 2.5, 3.1, 3.9 and 5 g/L from Golder and 0, 1.4, 1.8, 2.3, 3 and 4 g/L from Myrtle were investigated. Experiments were done at 27±3 °C temperature, relative humidity of 50±6 %and the photoperiod of 16:8 hours L:D. Results showed that the median lethal concentration (LC50) amounts of myrtle and golder were respectively 2.56 and 3.39 g/L and they were significantly different with each other (P<0.05). Also Golder extract up to 5 g/L concentration and the extract of Myrtle up to 4 g/L concentration, whitefly mortality was increased. The maximum mortality rates of B. tabaci related to the plant extracts were 79.8 percent at 5 g/L concentration of Golder, and 81 percent at 4 g/L concentration of Myrtle, respectively. Analysis of the interaction between the whitefly B. tabaci and the plant extracts showed that the maximum mortality was due to interaction between Golder at the level of 5 g/L, with Myrtle concentration of 2.3 g/L, 3 g/L and 4 g/L, created 95 %, 96.3 % and 97.3 % mortality, respectively.

The lady beetle Adalia decempunctata L. (Col.: Coccinellidae) is known as the ten-spotted ladybeetle, whose larvae and adults are active hunters. These insects have been reported from several stone-fruit trees, seed-fruit trees, broad leaved forest trees and coniferous forest trees infested with pests like aphids, mealybugs and psyllid from several countries on the world. The culture of this predator was maintained in laboratory condition (25 ± 2 ºC, 75 ± 5% RH and 16:8h L:D). In this research, the bioassays of pyriproxyfen was performed through topical application method. The concentration of IC10, IC30, IC50 and IC90 were estimated 18.6, 33.1, 49.3 and 130.6 µg/ml, respectively. Also, in order to have a better understanding, some of the most important biochemical parameters were evaluated in the 4th instar larvae treated with sublethal concentrations of pyriproxyfen. The results showed that lipid and protein amount were relatively increased compared to control, while the glycogen amount was reduced in treated larvae. The activity of detoxifying enzymes (Glutathione S-transferase and general esterases) in treated larvae were significantly increased compared to control. The activity of peroxidase was also increase significantly compared to controls. As the pyriproxyfen is a juvenile hormone analogue, therefore the growing stages of this predator is affected. While adults that have surpassed this stage are no longer dependent to growth hormones and are less affected. Hence, supplementary evaluation of the use of pyriproxyfen and this predator at the same time under field conditions is needed.

The mulberry scale pest Pseudoulacaspis pentagona (Targioni) (Hem.: Diaspididae) has entered Kiwi orchards causing worries to gardeners in recent years. The damages of this pest by feeding of both adults and nymphs from host plant sap, which weakens the plant and cause gradual death of the tree. In the current study, three geographical regions of Guilan province (i.e. west, east, and central) where the kiwi fruit is largely planted were selected. During 2015-2016 pest population changes and the rate of pest parasitism were studied. The results indicated variations in pest density in the studied areas. The spatial distribution pattern of nymphs and adults of these regions were aggregated and random. The highest pest density was recorded in 2015 from the east of Guilan (88.4 ± 14.25 adult scales in 10cm) while, 40.4 ± 4.09 and 77.8 ± 3.24 were recorded in 2016 and 2017 respectively. The Temperature fluctuations and parasitism by Encarsia berlesei Howard were found to be the limiting factors for pest activity. The presence of parasite was found to be remarkable in sampled areas. The highest number of parasitized was recorded in the third generation (38.78 parasited adult scales in 10 cm) from east Guilan in 2015. The annual parasitic activity rate of this parasitoid can be considered as one of the most important options in management of mulberry scale pest on the kiwi. The results could be improved and incorporated in management of this important pest.

In this study, the effects of four diets including standard food (68% wheat flour, 29% wheat bran and 3% yeast) and standard diets with oil additives including 10% palm oil, glycerin oil and pumice oil was studied on biological properties of Mediterranean flour moth. The study was carried out in a rearing chamber set at 25 ± 1 °C, relative humidity of 65 ± 5% and complete darkness. The fecundity rate was recorded (264.31 egg 250.54 egg and 335.03 egg in the diet containing pumice oil, glycerin oil and palm oil respectively that was significantly lower than standard diet (393.2 egg). There were significant differences in intrinsic rate of population increase (r) among diets, diets containing pumice oil (0.092 day-1), palm oil (0.101 day-1), glycerin (0.099 day-1) and standard food (0.109 day-1). Net reproduction rate (R0) in standard food (174.75 offspring /individual) was not significantly different from palm diet (127.31 offspring /individual), but significantly higher than pumice diet (76.65 offspring /individual) and glycerin diet (102.27 offspring /individual). Insect’s longevity in standard diet (52.86 day) was not significantly different from glycerin added diet (54.08 day) and palm (49.17 day) but the remaining diet had a meaningful difference. Therefore, diets containing palm, glycerin and pumice oil did not have much more efficiency than standard food for use in artificial diet based rearing this insect.

In this study, the effect of grafting of tomato on eggplant rootstock were investigated on growth indices of the tomato plant and biological parameters of Tuta absoluta (Meyrick) (Lep.: Gelechiidae). In order to evaluate of fertility and fecundity, a pair of adult insects (male and female) of T. absoluta, with less than 24 h age, were kept on each plant (grafted and non-grafted). Then, one egg (in 15 replications) was placed on each plant to measure the developmental period of embryonic, larval and papal stages until adult insect emergence. Seventy-five days after grafting, except the stem diameter, all growth indices of grafted plants including plant height, number of nodes and leaves were significantly higher than non-grafted plants. Also, weight of fresh and dry root of grafted plants were higher compare to non-grafted plants. Larval and pupal developmental period of T. absoluta fed on grafted plants were significantly higher than non-grafted plants. Besides, the mean fecundity of the adult female of T. absoluta was lower on grafted plants. Amount of total phenol content in different days after infestation with T. absoluta indicated a significant increase in grafted plant. Results of this research clearly showed that the grafting of tomato plants on eggplant rootstocks could be an effective approach for increasing of plant growth and subsequently its resistance to T. absoluta.