PLANT PEST RESEARCH
Year:2020 | Volume:10 | Issue:1|Papers Count:8

The aim of this study was to investigate the potential of traps for releasing Metarhizium anisopliae Metsch in a population of date palm horned beetle Oryctes elegans Prell. The structure used in the trap consisted of an absorber section, stopper plates, pickup hopper, and trap chamber. In order to study different pheromone and dietary compounds in the trap predation rate, three treatments in three replications were cumulative pheromone, integration (cumulative pheromone and nutrient absorber) and nutrient absorber containing 20 g of date palm meristem. Insect retention time and concentration of inoculum were standardized to achieve maximum trap efficiency in adult insemination. Hence, five times of 20, 30, 40, 50 and 60 seconds and 5 concentrations of 104, 105, 106, 107 and 108 spore/mL were considered. The final dimensions of 350×350×650 mm trap were made using standard workshop methods. The results showed that the type of attractant had significant effects on trapping efficiency of adults. The highest rate of insect trapping was observed in the combination of cumulative pheromone and date meristem and the lowest was found in the date meristem alone. The highest rate of trapping occurred at 8 pm. The best time and concentration for maximum male and female inoculation were 54. 3 and 55. 7 seconds as well as 4. 14×104 and 4. 36 104 104 spores/ml, respectively. The results of the present research showed that the smart releasing trap of M. anisopliae as a pathogenic agent of the population of palm horned beetles possess the required efficiency in laboratory conditions.

The apple armored scale, Lepidosaphes malicola Borchsenius (Hem.: Diaspididae) an important pest of fruit trees. Control of this pest depends mostly on the use of chemical pesticides. To study the effect of several pesticides on the pest population, two separate experiments were conducted in a randomized complete block design with three replications in two orchards. The first factor was treatments [control (water), spirotetramat 0. 5 and 0. 75 ml/L, flupyradifurone, thiacloprid, and pyriproxyfen 0. 5 ml/L]. The second factor was the sampling time (1 day before and 1, 3. 5, 7, 14, 21, 28 and 35 days after treatment). Spirotetramat and flupyradifurone (with more than 80 percent mortality) had the most effect on the nymphal mortality. The mortality in thiacloprid and pyriproxyfen was lower than that of spirotetramat and flupyradifurone. By considering the treatment time, the mortality rate of nymphs by flupyradifurone, a butenolide with knockdown effect reached its highest level one day after treatment. In 0. 75 ml/L concentrations of spirotetramat the highest decrease in the nymphal population was observed one week after treatment. Spirotetramat with up and down bilateral movement ability is a very long-lasting systemic insecticide. Results indicated a negligible effect of the pesticides on adult mortality under female shields. The use of 1. 5-2 percent volck® oil in winter spraying had a significant effect on pest control. Overall, spirotetramat and flupyradifurone showed a significant effect on the nymph’ s control and can be recommended.

The snail, Helicella candaharica (Pulmonata: Hygromiidae) is one of the most important terrestrial mollusk pest of field and orchards in Mazandaran province. The aim of this study was investigating the efficacy of different treatments in control of H. candaharica in lettuce and tomato fields. The treatments were copper sulfate (2. 1 g/m2), metaldehyde (2. 7 g/m2), Ferricol® (4 g/m2), Cuprex® (1 ml/m2) and two sawdust treatments; a 15-cm barrier was created around the half of the plants in first sawdust treatment and around the all of the plants in second sawdust treatment. 840 and 1350 snails were released within the plots in first and second field experiments, respectively. The results indicated more efficacy of Ferricol® in comparison with the other treatments in both lettuce (78. 3%) and tomato (80. 2%) field experiments at 21 days after treatment. The Cuprex® was ranked as the next treatment where its effectiveness was 48. 3% in lettuce and 59. 9% in tomato field. The metaldehyde treatments were more effective in tomato (55. 7%) than lettuce (33. 7% control) field. There was no significant difference between sawdust (average of 36%) and copper sulfate (average of 38% effectiveness) treatments. The results of this study demonstrated the appropriate ability of Ferricol® for replacement of the current chemical molluscicide, metaldehyde.

Vegetable leaf miner, Liriomyza sativae Blanchard (Diptera: Agromyzidae), is one of the most economically important pests of agricultural products, including vegetables and ornamentals. The larvae feed on leaf mesophyll and reduce photosynthesis and yield. Identifying more effective insecticides and choosing the suitable treatment method can be very important in managing this pest. In this study, the insecticidal effect of chlorantraniliprole, spirotetramat, dimethoate and diazinon were investigated on 1 st instar larvae of L. sativae. The study was conducted under greenhouse condition at 26 ± 2° C, 60 ± 10% RH and 16: 8 (L: D) h photoperiod. Preliminary experiments were performed to compare the insecticidal effects of leaf and root treatment of each insecticide. Leaf treatment was performed using leaf dipping method and soil treatment carried out by adding a certain amount of insecticide solution into the soil of each pot. Lethal concentrations were estimated for the treatments which caused higher mortality of the larvae. The results showed that only soil treatment of dimethoate (LC50: 53. 73 mg ai L-1) was more effective than its leaf treatment (LC50: 162. 91 mg ai L-1). The LC50 values for leaf treatment of chlorantraniliprole, spirotetramat and diazinon were 0. 24, 6. 11 and 53. 72 mg ai L-1, respectively. Considering the results of the bioassays, treatment of plant leaves by chlorantraniliprole and spirotetramat, and treatment of plant soil by dimethoate are proposed as effective insecticides and suitable treatments to control this pest.

Canola is cultivated as an oil seed plant all over around the world. The mustard aphid, Lipaphis erysimi (Kalt. ) (Hem.: Aphididae) is one of the most important canola pests. In this study, the lethal and sublethal effects of flupyradifurone were evaluated on biological characteristics and life table parameters of the mustard aphid. The experiments were carried out at 20± 2oC, 65± 5% RH and 16L: 8D photoperiods. The life table parameters of L. erysimi were calculated using Carey's life table method. The LC50, LC25, and LC10 values of the flupyradifurone insecticide were 0. 385, 0. 093, and 0. 026 mg/L, respectively. The intrinsic rate of increase (r= 0. 34, 0. 30, and 0. 23 Female/female/day), finite rate of increase (λ = 1. 41, 1. 36, and 1. 27 Female/female/day), mean generation time (T= 10. 84, 9. 98, and 9. 00 d) and doubling time (DT= 0. 49, 0. 50, and 0. 54 d) were calculated in control, LC10, and LC25 treatments, respectively. The highest rates of reproduction and population growth rates of the mustard aphid, L. erysimi population were related to control, LC10, and LC25 treatments, respectively. Experiments showed that the sublethal effects of flupyradifurone significantly reduced gross rate reproduction, intrinsic rate of increase, finite rate of increase and mean generation time and increased doubling time of mustard aphid. Therefore, according to the results of this study, the insecticide flupyradifurone has a good potential in controlling mustard aphids in lethal and sub-lethal concentrations.

The activity of general esterases (ESTs), catalase (CAT) and glutathione S-transferase (GST) were used to survey the in vivo responses of Glyphodes pyloalis Walker to bare carbon nanotubes (CNTs) and synthesized carbon nanotubes/titanium dioxide nanoparticles (CNTs/TiO2-NPs). These biochemical tests were performed in the three time points of exposure (i. e. 24, 48 and 72 h) and to five concentrations (i. e. 100, 200, 300, 400 and 500 ppm). Results showed that the enhancement of treated concentrations of both CNTsand CNTs/TiO2-NPs irreversibly impaired ESTs activities when α-naphthyl acetate (α-NA) used as a substrate. Using β-naphthyl acetate (β-NA) as a substrate, inhibitory effect of both CNTs and CNTs/TiO2-NPs on ESTs activities was more intense than that of α-NA. Results also demonstrated that inhibition of GST activities generating by bare CNTs and also by CNTs/TiO2-NPs was dependent to the concentrations of treatments. CAT assays showed that the increasing CNTs concentrations over exposure time could be affected by enhancement of the CAT activities in G. pyloalis. In the similar manner to bare CNTs, the increasing CNTs when coupled to TiO2-NPs (CNTs/TiO2-NPs) over exposure time could be interfered to the CAT activities. It can be concluded that these tested enzymes are good early biochemical indicators in order to prediction and management of adverse effects of bare CNTs and also CNTs when coupled to TiO2-NPs on insects.

Poplar clearwing moth, Paranthrene tabaniformis Rott. (Lep.: Sessiidae) is an important poplar pest in Asian, European, African and North America and it's reported by Farahbakhsh from Iran in 1962. In current research, biology of P. tabaniformis was studied mainly in Safrabasteh Poplar Research Station, as well as Fakhr Abad (Lasht-e nesha) and Pillambara (Paresar) stations, the Lakan nursery and some private nurseries in Kiashahr and Ziabar in Guilan province. Adults of this pest are resemble wasps, emerge from Mid-May and operate until Mid-September. Females mate after emergence and the eggs are laid individually, pairs, and rarely more in different directions at a height of 30 cm to 2. 5 m on the creases of the stems, as well as under the leaves and margins of the lateral buds. The embryonic period is 10 to 14 days and the larvae create a small cavity in the bark, usually at the petiole-to-stem junction, after hatching and then they penetrate into the soft stems and gradually form galleries. The maximum length of larval galleries was 25 cm. Larval activity of this pest was observed by creating galls on one-year-old poplar stems of different poplar clones of euramericana and deltoides species with different intensities in Guilan province. Severe infestations of seedlings can result in stem breakage under wind impact. Wintering of the insect is the form of third to sixth stages of larvae. The activity of larvae is resume in April and become pupae after a while. The pupal period is between 17-19 days. P. tabaniformis has one generation per year.

The use of colored sticky traps is very common in population monitoring and pest management. The color trap attractiveness and capture rates of thrips vary according to species and trap color. Different color preferences of many thrips species have been studied by numerous scientists to enhance the attractiveness and sensitivity of various traps. In this study, the attraction of thrips by colored traps (blue, yellow and white) in the oak forests of Khoran and Kalan regions located in Eyvan city (Ilam Province, west of Iran) was investigated in 2018. The results showed that in both Khoran and Kalan regions, in all sampling months (except December), the blue sticky traps attracted significantly more thrips than other sticky traps. In the Khoran region, the highest number of attracted thrips with a value of 19. 80 ± 1. 35 was related to blue traps and the May, and the lowest number of attracted thrips with a value of 1. 01± 0. 44 was related to white and August. In addition, in the Kalan region, the highest and lowest number of thrips with a value of 15. 80± 1. 35 and 1. 80± 0. 3 were related to blue and yellow sticky traps in May and December, respectively. Generally, the results of this study showed that the efficiency of blue sticky traps was more than yellow and white traps. Overall, the use of blue sticky traps is appropriate for monitoring thrips on oak trees in the spring season.