جستجوی مقالات مرتبط با کلیدواژه « aphis gossypii » در نشریات گروه « گیاهپزشکی »

Seasonal population dynamics of the aphids on two important commercial citrus species, Thomson navel orange (TNO) and Satsuma mandarin (SM) were investigated in the west of Mazandaran province, Ramsar, during 2015-2016. Samplings were performed biweekly from April 2015 to July 2016. In each sampling date, four young shoots were randomly selected from each main geographical direction of each tree and the number of aphids was counted under a stereomicroscope. The Pearson correlation coefficient was used to determine the relationship between aphid density and temperature and relative humidity as variables. For both species of citrus, the results showed that the first and second population peaks of the aphids occurred in May and October, respectively. Furthermore, there was a significant difference between the infestations of both citrus host plants by the aphids, with Satsuma mandarin showing more infestation. There was a significant difference among the population densities of different aphid species on both citrus species. Aphis spiraecola, Aphis gossypii, and Toxoptera aurantii had the highest population abundances, respectively. A positive and significant correlation was observed between these citrus aphid population densities and temperature (r= 0.689, n=49, P=0.04), however, the correlation was not significant for relative humidity (r= 0.661, n=49, P=0.53). In total, seasonal population dynamics of the citrus aphids were affected by the host plant species and different species showed different population fluctuation trends.

The Melon Aphid, Aphis gossypii, is a key pest of greenhouse cultivated cucumber which is economically important due to its wide host-range and cosmopolitan status. Due to its high potential for evolving resistant biotypes against insecticides, it is necessary to test and present new insecticides against it. This research was conducted in the greenhouses of Tehran and Yazd provinces, based on a completely randomized design with 6 treatments and 4 replications. Treatments  included pirimicarb (WP 50%)  at the rate of 1/1000 L, flonicamide (Teppeki ® WG 50%)  at the rate of 0.2/1000 L and 0.25/1000 L, pymetrozine (Chess ® WG 50%)  at the rate of 0.5/1000 L, palizin insecticide soap  at the rate of 2.5/1000 L and control (water spray). The sampling was done one day before the treatment and 3, 7 and 14 days after the treatment. Analysis of variance of data was performed by SAS software and means were compared using Duncan multiple range Test. On the third day after treatment, the mean efficacy of Teppeki (0.2/1000 L), pirimicarb, pymetrozine, Teppeki (0.25/1000 L) and palizin was 97.83%, 87.7%, 82.43%, 90.53% and 76.94%, respectively. On the seventh day after treatment, the highest and the lowest efficacies were observed in Teppeki (0.25/1000 L) and palizin treatments, which were 92.27% and 38.7%, respectively.   The mean efficacy in Yazd province, on the third day after treatment was 90.25%, 79.66%, 86.28%, 88.74% and 75.25% for Teppeki (0.2/1000 L), Teppeki (0.25/1000 L), pirimicarb, pymetrozine, palizin, respectively. In general, the new insecticide, Teppeki, has an acceptable efficacy against this pest in the greenhouse.

Cucumber, Cucumis sativus L. is one the most important economic vegetables crop cultivated in Iran and many countries of the world. The cotton-melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most destructive polyphagous pests of Cucurbitaceae plants in greenhouses and open fields. A. gossypii can cause severe damage in commercial fields. The honeydew that aphid excretes decreases the photosynthetic activity of plants and contaminates fruit, resulting in severely reduced quality. Moreover, A. gossypii can transmit more than 80 type of viral diseases that can cause substantially greater losses than the damage from direct feeding of the insect. The focus of the control methods against this pest in our country is the use of insecticides. Additionally, A. gossypii has developed different levels of resistance to many insecticides. Agricultural adjuvants can improve the efficacy of pesticides and can be effective in reduction of pesticides use. In the current research, the effects of two adjuvants (Scorch and Torpedo п) on efficiency of imidacloprid (SC35%) and flonicamid (WG50%) to control this aphid were investigated on cucumber in greenhouse. These two insecticides have systemic property doing their job after leaf penetration. It is known that the leaf penetration step is very determinative for systemic pesticides. Besides, Scorch and Torpedo п are multi-functional adjuvant, showing penetration, wetting, adhesion and spreading properties.

The project was performed based on a completely randomized design with 15 treatments and 3 replicates. The efficacy in the sampling units was recorded at 1, 3, 7 and 14 days after treatment. The treatments were: 1) imidacloprid (recommended dose); 2) imidacloprid+Scorch; 3) imidacloprid+Torpedo п; 4) imidacloprid (10% reduction of dosage)+Scorch; 5) imidacloprid (20% reduction of dosage)+Scorch; 6) imidacloprid (10% reduction of dosage)+Torpedo п; 7) imidacloprid (20% reduction of dosage)+Torpedo п. Flonicamid was replaced by imidacloprid in the treatments 8 to 14. The control treatment (No. 15) was sprayed by water only. The efficacy was calculated using the Henderson and Tilton formula. Statistical analysis was performed using the SAS software (ver. 9.1). One row was considered as the distance between the experimental units. Two rows on either side of the greenhouse were also considered as margins.

The combine analysis of variance showed that interaction of treatment × place was not significant, meaning that the experimental treatments had the same respond in different locations. Therefore, the data were statistically analyzed based on this, without considering the locations (Urmia and Karaj). The results showed that both adjuvants were able to improve the efficacy of imidacloprid and flonicamid, as it was confirmed at all times after spraying. For example, three days after spraying, the efficacy of imidacloprid alone was estimated at 81.47%, while "imidacloprid + Torpedo" and "imidacloprid + Scorch" were estimated at 92.60% at 93.43%, respectively. Similarly, seven days after spraying flonicamid alone showed 87% efficiency, whereas the treatment of "flonicamid+Torpedo" and "flonicamid+Scorch" exhibited 94.34% and 95.31%, respectively. When Torpedo п was used in combination of reduced doses of imidacloprid, the efficacy was severely reduced. Thus, the addition of Torpedo п is not recommended with reduced doses of imidacloprid. Instead, adding the Scorch when reducing the imidacloprid dosage, the efficacy was remained as high. For example, three days after spraying, "Imidacloprid with 10% dose reduction + Scorch" and "Imidacloprid with 20% dose reduction + Scorch" treatments were 93.65% and 94.23% efficacy, respectively. Besides, by reducing the flonicamid dosage and adding both adjuvant, the efficiency was as high as to the treatment using the recommended dosage. For example, 14 days after spraying, flonicamid with 10% dose reduction + Scorch and flonicamid with 20% dose reduction+ Scorch showed 93.94% and 93.48% efficacy, respectively. Our results can be important from both economic and environmental point of view, as the obtained results indicated that imidacloprid and flonicamid dosage can be reduced by 20%. However, it should be keep in mind that other factors, such as the price of adjuvants, are involved in their practical and field use by farmers, which should be taken into account.

Background and Objectives:

 The melon aphid, Aphis gossypii Glover, is one of the most important pests of tomato in Iran. This aphid causes severe damage on tomato crop in northern Iran. 

Materials and Methods:

 Present study was conducted in an experimental field, 0.3 h, in Behshahr region in Mazandaran province based on a randomized completely block design. In this study, the effectiveness of intercropping tomato (T) with clover (C) in the three combinations: (1) one row of tomato with two rows of clover (1T:2C), (2) two rows of tomato with two rows of clover (2T:2C), and (3) three rows of tomato with two rows of clover (3T:2C) along with sole tomato were assessed on the densities of melon aphid, Aphis gossypii Glover, diversity of its natural enemies and yield of both crops in 2016 and 2017.

 Results:

 The density of nymphs and adults of A. gossypii were significantly higher in sole tomato compared with intercrops. Among intercrops, the lowest density of nymphs and adults of A. gossypii were observed in 1T:2C intercrop. In present study, 13 predator species were collected and identified on aphid-infested plants of tomato in the experimental field. Among the predators, Coccinella septempunctata L., Chrysoperla carnea (Stephens) and Episyrphus balteatus DeGeer had more abundance in the two studied years.  The Shannon diversity index (H´) and the Pielou’s evenness index (J´) for composition of predator species were significantly higher in intercrops compared with sole tomato crop. Moreover, more nymphs and adults of A. gossypii were parasitized in all intercrops compared with sole tomato crop in 2016 and 2017. The highest value of land equivalent ratio was found in 1T: 2C (LER = 1.28 in 2016 and 1.30 in 2017) among intercrops in the two cropping seasons.   

Discussion:

 All the three intercropping patterns of tomato with clover including 1T:2C, 2T:2C and 3T:2C, especially 1T:2C could be recommended in management programs of the melon aphid in tomato fields.

Light, as an environmental factor, affects the biology, physiology and behavior of insects. In this study, the feeding behavior of Hippodamia variegata and parasitism rate of Lysiphlebus fabarum were studied under light and dark conditions. Synchronous cohorts of different growth stages of H. variegata and female parasitoid wasps were produced and then they were singly introduced into experimental arena containing third instar nymphs of Aphis gossypii (20 nymphs for second instar larvae and female wasp; 30 nymphs for other growth stages of ladybird beetle) on a cucumber leaf. The results revealed that, although light did not influence foraging behavior of second instar larvae of the ladybird beetle, the number of killed aphids was significantly higher for fourth instar larvae by female and male adults of H. variegata during foraging in the light condition in comparison with the dark condition. The ratio of partial prey consumption (No. of partially consumed aphids to No. of aphids killed) was significantly greater in fourth instar larvae than in second instar larvae in the dark condition. Female adults displayed significantly more partial consumption of prey in the dark relative to the light condition. Moreover, in both light and dark phases, this ratio was higher in female adults than in males. The results revealed that female wasps parasitized fewer A. gossypii nymphs in the dark than in the light. Based on the acceptable performance of H. variegata in the dark condition, it can be said that in addition to the benefits of simultaneous application of the parasitoid wasp and the ladybird beetle during the day, aphid population decline continues at night.

The melon aphid, Aphis gossypii Glover is a polyphagous and cosmopolite species which is widely distributed in moderate and tropical regions of the world. The high-risk chemical pesticides are currently used to control this pest that have environmental impacts and also affect non-target organisms. Therefore, in order to cope with this situation, we must think about the safe alternatives to control this pest. In the current study, chemical composition and fumigant toxicity of the essential oil from wild mint, Mentha longifoliaL. was studied against the nymphal and adult stages of the melon aphid, A. gossypii. The essential oil was obtained by hydro-distillation method, using a modified Clevenger-type apparatus. The amount of this essential oil was determined by mass chromatography method. Bioassay experiments were performed in a completely randomized design with five concentrations (0.1 to 0.9 μl/L air) and three replications. For each replicate, 10 samples of the last instar nymphs and adult aphids were separately considered. Also, nymph production deterrent effect of the oil at sublethal concentration of the oil was studied against the parthenogenesis form of aphid. Results indicated that essential oil of M. longifolia is highly toxic to the melon aphid.The major components in the oil were Pulegone (44.75%), Menthone (30.80%), 1,8- Cineole1 (5.49%) and Cyclohexanone, 5-methyl-2-(1-methylethyl)- (2R-cis (2.06%). Probit analysis showed that the LC50 values for nymphs and adults of A. gossypii were 0.059 and 0.0081 µl. L-1 air, respectively. By increasing the concentration of essential oil, the mortality rate also increased. Also, degree of nymph production deterrent effect was calculated for the essential oil of M. longifoliaas 80.03±3.68%. The overall results showed that the wild mint essential oil has a high potential in controlling the melon aphid especially in protected areas such as geenhouses.

Melon aphid, Aphis gossypii, is an important pest of cucumber in greenhouses. In this research the possibility of using induced resistance for reducing population growth rate of the pest has been investigated. The life history parameters of aphid were determined in a growth chamber at 25±2° C, 60 ± 5% R.H and 14:10 L D conditionsin a completely random design in a split plot experiment. The main factor was two cucumber cultivars of Royal and Storm and the subplot consisted of five different pre-infestation periods (0, 2, 4, 6 and 8 days pre-infestation with five melon aphid/plant). At the end of each pre-infestation period, the aphids were removed and the plants kept aphid-free for 48 h. The life history and population growth parameters of aphid were determined through 40 replications. The results indicated that there were significant differences among the treatments in aspect of the nymph growth duration, duration of reproduction of adult aphids and the longevity of the adult aphids. Furthermore, among the treatments R0, r, λ and DT had significant differences in both cultivars, but there was no significant difference among the treatments in terms of generation time (T). The lowest and highest R0 in Royal (19.27 and 49.65 nymph/female/generation)and the lowest and highest r(0.311and 0.480 /day) were observed on 6 and 0 days pre-infestation period treatments, respectively. The lowest and the highest R0 in Storm (13/25 and 44/63 nymph/female/generation)and the lowest and highest r(0.273and 0.463 /day) were observed on 6 and 0 days pre-infestation period treatments, respectively. WE conclude that the pre-infestation of the cucumber plants with A. gossypii can induce resistance in cucumber within 6-8 days leading to population growth rate reduction in the melon aphid.

The common pistachio psylla (CPP), Agonoscena pistaciae Burckhardt and Lauterer, 1989 (Hem.: Psylloidea: Rhinocolinae) is an important pest of pistachio trees. The presence of a large population of psyllid causes severe problems such as falling buds and leaves and therefore this pest causes heavy economic damage to farmers. Predators are the largest and the most diverse natural enemies of the CPP. They are offered as biological control agents against pistachio pests, especially CPP, although they are mostly general predators. Oenopia conglobata contaminata (Menteries) is one of the common psylla predators of pistachio orchard that have a significant role in biological control of Agonoscena pistaciae population. Despite the importance of this efficient predator, the limited study has been done on the effect of different hosts on the biological parameters of this lady beetle. In this study, the demographic parameters of this lady beetle by feeding on 4 different prey species, A. pistaciae , Aphis fabae Scopoli (Hem.:Aphididae), Aphis gossypii Glover (Hem.:Aphididae) and eggs of Ephestia kuehniella (Zell.)(Lep.:Pyralidae) were studied in the laboratory conditions (25 ± 2°C, relative humidity of %65 ±5 and photoperiod of 16 hours light and 8 hours of darkness).
Nymphs of CPP (A.pistaciae) and adults of O. conglobata contaminata beetles were collected on the pistachio leaves from a pistachio orchard. Aphids (A. fabae and A. gossypii) were reared on the bean and the cotton plants planted in a greenhouse. Eggs of E. kuehniella were prepared from insectarium of Kerman Plant protection management and rearing of E. kuehniella was done in the laboratory conditions in Kerman Agricultural and Natural Resoarce Research Center. Before starting the experiment, one generation of O. conglobata contaminata was reared in the laboratory on the different host separately. One hundred eggs of O. conglobata contaminata were used to determine the demographic parameters. After hatching of eggs, larvae was individually transferred to a plastic container (5*10 cm) and kept in a growth chamber. Every day the larvae were fed with the above mentioned host. Their growth and development were monitored daily and also mortality rate was recorded. In the experiments, fourth-instar nymph of the aphids and A. pistaciae were used. The raw data of the developmental time and female daily fecundity of O. conglobata contaminata individuals were analyzed based on the age-stage, two-sex life table using the computer program TWO SEX MS Chart.
Results showed that the maximum net reproduction rate (R0) and intrinsic rate of increase (rm) in psylla diet was 290.87 , 0.1559, respectively and the minimum of R0 and rm belong to eggs of E. kuehniella diet (61.68 and 0.1103). This result proves that psylla diet is the best food for O. conglobata contaminata and aphids diets were in the next ranks (R0 and rm in A.fabae and A.gossypii diets were 200.48, 0.140; 72.44,0.128, respectively). Results of mean generation time of O. conglobata contaminata that was rearing on different diets showed that there were significant differences among the different diets. Mean generation time of O. conglobata in Psylla, A.fabae, A.gossypii and egg of E. kuehniella diets were 36.31, 37.72, 33.34 and 37.30 days, respectively. Finite rate of increase (λ) of O. conglobata contaminata by feeding A.pistasciae, A.fabae, A.gossypii and E. kuehniella was determined 1.198, 1.150, 1.136 and 1.116, respectively.The results of this study can be compared with the result of Mokhtari and Samih (2014), Rounagh and Samih (2014) and Hassani et al. (2009). Life expectancy of female and male O. conglobata contaminata by feeding A.pistasciae, A.fabae, A.gossypii and E. kuehniella were 80.82,64.16; 81.02,68.76; 80.54,68.88 and 59.75, 62.11 days, respectively. Results also indicated that the psylla and A.fabae diets improved the demographics parameters and the life expectancy of O. conglobata contaminata.
The results illustrated that this predator by feeding on nymphs of A. pistaciae has the highest intrinsic rate of increase (rm) and with respect to the demographic parameters, it was the most suitable prey .The compare of O. conglobata contaminata -rm that rearing by CPP with A. pistaciae -rm proves that this predator can control of A. pistaciae in the field and this ladybeetle can be used in IPM of pistachio orchards. According to the difficulty of rearing CPP in laboratory conditions, aphids are suitable preys for mass rearing of O. conglobata contaminata in insectariums.

Intraguild predation is defined as killing and eating another predator species as potential competitors that depends upon the same or limited resources. In this study, intraguild predation between the ladybird Hippodamia variegata Goeze and the parasitoid wasp Lysiphlebus fabarum (Marshall) was investigated in association with cotton aphid, Aphis gossypii, on cucumber plants. Host preference for healthy or previously parasitized aphids in third instar larvae and adult females of H. variegata was studied in a choice access situation as well as in a Y-tube olfactometer bioassay. We cut an antenna of each experimental aphid to reliably distinguish the parasitized aphids from healthy ones. All experiments were performed at 22±1°C, 60%–70% RH, and a 16:8 (L:D) photoperiod. Based on the pre-test results, cutting the antenna of aphids, did not significantly affect the host preference of adults or third instar larvae of ladybirds. In a choice access test, female ladybirds significantly preferred healthy aphids to previously parasitized ones (24 and 72 hours: t =2.15, df =1,18, P =0.04 and t =6.35, df =1,18, P

Oenopia conglobata is an important active predator of pistachio psyllid in pistachio orchards. Alternative host or prey has an important role in the stability of natural enemies population in nature. In this study, prey preference of 4th larval instar, male and female of O. conglobata were examined in 10 replications. Nymphs and adults of Agonoscena pistaciae, Aphis fabae, Aphis gossypii and eggs of Ephestia kuehniella with corn pollen were used as preys. In order to study the effects of these preys on consumption rate of adult stage of O. conglobata when feeding only on the common pistachio psylla, it was reared on each diet separately and the feeding percentage was determined after 24 hours. The results showed that the larvae and adults of this predator prefer nymphs of pistachio psylla to other preys. They fed 87±1.52 and 85.5± 1.74 % of psyllid nymphs, respectively. The Manly preference index in the prey-preference test on different diets also showed more preference to nymphs of pistachio psylla compared to other diets. Those predators reared on psylla had more consumption rate on pistachio psylla nymphs (99.2±0.512 %) than to other preys. The results showed that O. conglobata preferred common pistachio psylla to other preys and the common pistachio psylla is a suitable prey for rearing of this predator, but due to feasibility and rearing expenses, A. fabae as a second prey is the most favourable prey for rearing of O. conglobata for biological control of A. pistaciae.

Predatory damsel bug, Nabis pseudoferus Remane has a high density in the alfalfa fields and feeds on different types of prey. In this study, biological properties and life table statistics of N. pseudoferus by feeding on melon aphids have been determined under controlled conditions (at 25±1˚C, 60±10% relative humidity and under a photoperiod of 16h light/ 8h dark). Data analysis carried out based on age-stage two sex life table program. The results indicated that the mean duration of eggs, 1st instar, 2nd instar, 3rd instar, 4th instar, 5th instar nymphs and adult longevity was 9.00±0.05, 2.89±0.02, 2.86±0.02, 3.10±0.03, 3.67±0.03, 5.87±0.05 and 19.47±0.52, days respectively. Life table statistics include r, R0, GRR, λ and T were estimated as 0.06±0.002 day-1, 16.39±1.99 eggs/individual, 59.58±6.16 eggs/individual, 1.07±0.002 day-1 and 43.97±0.31days, respectively. The death and birth rates for this predator by feeding on melon aphid were determined 0.02 and 0.08, respectively. With regard to predatory habit of most life stages of N. pseudoferus and longevity of adults, this predator could be considered as a potential candidate for reducing cotton aphid populations.

Aphis gossypii Glover (Hom.: Aphididae( is one of the most important pests in greenhouse and field. Considering the importance of human health and the environmental protection, reduction in pesticide application has to be considered as an essential issue in the pest control program. In the present study, effects of ethanolic extracts of Rosmarinus officinalis L. and Nerium oleander and an insecticide, imidacloprid were evaluated against Aphis gossypii. Leaf dipping method was used in the laboratory conditions (temperature of 25 ± 1 °C, 65 ± 5% relative humidity and 16 h light: 8 h dark). After 72-h, LC50 values of imidacloprid, plant extracts from rosemary and oleander were estimated 0.004, 24.69 and 45.26 mg/ml, respectively. In this study, the effects of sublethal concentration (LC30) of each treatment was evaluated against A. gossypii. Longevity and the number of offspring were estimated per female per day. In this experiment, significant effects were observed on the life table parameters such as survival, intrinsic rate of increase, net reproductive rate, finite rate of population increase and mean generation time, for aphids fed on the leaves treated with ethanolic plant extracts and imidacloprid as compared to the related controls. This information provides further support for plant extracts of R. officinalis and N. oleander having a good potential to control the A. gossypii. However before claiming firm conclusions, trials under glasshouse and field related conditions are needed to verify the applicability of these two plant extracts in control of A. gossypii.

Imidacolprid and pirimicarb are conventionally used insecticides for controlling melon aphid، Aphis gossypii Glover in fields and glasshouses in Iran. Aphidius matricariae Haliday is one of the most impotant parasitoid wasps of A. gossypii. The sublethal effects of mentioned insecticides were investigated on orientation behaviour using olfactometer device. The mortality data were subjected to probit analysis for lethal concentrations calculations and confidence limits. Concentrations of 0. 3 and 4. 2 ppm (LC25) of imidacloprid and pirimicarb، respectively، were used for olfactometer tests. Adult females were exposed to dry residues on glass tubes for 24 h. Three day old survived wasps were used for orientation tests. Results showed that imidacloprid and pirimicarb had no effects on orientation behaviour of female wasps to the odour of cucumber leaves that were infected by melon aphid although orientation response of female parasitoids toward contaminated leaves to honeydew of aphids was affected by exposure to LC25 of two insecticides. But in all of the tests، access times to treatments by parasitoid wasps exposed to imidacloprid significantly exceeded control.