Journal of Entomological Society of Iran
Year:2007 | Volume:27 | Issue:1 (39)|Papers Count:12

Some biological aspects of Emposaca decipiens Paoli were investigated on different bean species (Phaseolus vulgaris L., P. lunatus L., P. calcaratus Roxb. and Vigna sinensis L.) under field and laboratory conditions (26 ± 1oC, RH: 70 ± 5% and a photoperiod of 16L: 8D h.). The species of the host plant had no significant effect on incubation period, but the nymphal instars, development time, adult longevity and life span were affected by host plant species significantly. The shortest and longest development time in the field condition were occurred on V. sinensis (22.58 ± 0.50) and P. calcaratus (27.17 ± 0.67), respectively. But in laboratory conditions these parameters were observed on V. sinensis (20.71 ± 0.57) and P. vulgaris (29.29 ± 1.00), respectively. Adult longevity on V. sinensis had the longest duration. In contrast, the shortest adult longevity was observed on P. vulgaris. Surface of the leaves in V. sinensis is smooth and without trichomes, but presence of the hoocked trichomes on three other host plants especially in P. vulgaris assumed as the most important reason of their unsuitability for the leafhopper.

Fields of winter wheat and barley were sampled during two years (November to June 1996-1998) in Golestan province to determine the occurrence, frequency and distribution of thrips species. A total of 32 species belonging to 3 families and 16 genera were found. Haplothrips tritici (Kurdjumov) was the dominant species accounting for 70.2% and 55.7% of identified individuals in wheat and barley, respectively. Sitothrips arabicus Priesner was the second most abundant species, comprising 13.5% and 20.1% in wheat and barley, respectively. Regression analysis showed a non-linear relation (y=42.65+0.33x-0.0002x2) between altitude (x) and population density of H. tritici (y) on wheat. Locality and date of collection, host (s) and distribution data for each species are given.

Parapodia sinaica Frau. is among one of the important pests of tamarisk (Tamarix spp.) in Qom province. During 2000-2003, the biology of this pest was studied by periodic samplings of its different life stages every 15 days using light traps in natural tamarisk fields (Masileh region - Qom salt lake) and rearing some life stages in transparent dishes containing a tamarisk stem in laboratory conditions (50 ± 5% RH, 25 ± 1oC and a photoperiod of 16L: 8D h.). P. sinaica overwinters as 4th or 5th larval instars in the galls. In early March, larvae change into pupa and the pupal period lasts 52 ± 5 and 44 ± 3 days in field and laboratory conditions, respectively. Flight peak of the adult moth took place in early May. The moth being fed on water and sugar survived 14 ± 3 days and preoviposition period lasted 2.3 ± 0.49 days. Average egg number deposited by a female in natural conditions was 32 ± 7. Oviposition period lasted 7.2 ± 0.83 days and incubation period of eggs was 29 ± 3 and 25 ± 2 days in the field and laboratory conditions, respectively. This insect has five larval instars and the mean developmental time of the first to the fifth larval instars were 63 ± 5, 46 ±.34, 44 ± 3.8, 50 ± 5.3 and 97 ± 6.2 days, respectively. The pest has one generation in a year. Larvae never feed on the wood but they feed on bark and cause die back of the branches in the end of the next year. Activity of this pest was also observed in Isfahan, Khuzestan, Qom and Yazd provinces.

Chickpea, one of the major pulses, is planted together with wheat as a custom rotation in Ilam province. Pod borers are serious pest of chickpea and their direct damage to seed reduce yield considerably. Annually, farmers use much pesticide against the pest without any clue. In order to determine economic injury level (EIL), a semi-field study was started in 2000 to calculate this parameter based on a complete randomized block design with five treatments and four replications. Emerged larvae in the surrounding chickpea fields were collected and released in cages at the density of 0, 10, 20, 40, 80 larvae per square meter. Various factors (e. g. yield, damaged and total seeds) were measured and analyzed at harvesting time. Results show that if market value of chickpea and cost of management (treatment) are considered 3500 rials per kg and 150000 rials, respectively, then EIL will be 3.9 larvae per square meter (four rows with a length of one meter).

The monobasic genus Sphaeropothrips is recorded in Iran for the first time. This is the fourth member of the Thrips genus-group recorded from Iran, and a key is provided to distinguish these four genera. Information about these four genera is provided, and some problems in the recognition of true host-plant associations in Iran are discussed.

This experiment was conducted in Safiabad Agricultural Research Center for two years starting from 7th October 2001 in order to evaluate and selection of the best cultural, chemical and integrated control methods of Protapion trifolii (L.) (Col.: Apionidae) in Berseem clover. The effects of control methods were investigated using 9 experimental treatments (including chemical and cultural controls, and the integration of these two methods) in the form of a 2-factor split plot design with 3 replications. Vertical factors were two insecticides, Ecamet and Durseban, and an "untreated" treatment, and horizontal factors were the dates of second mowing (for seed) in 1st, 16th & 31st March 2002. In order to evaluate the amount of damage and the effects of different control methods on yield components, the percentage of inflorescence infestation to larvae before and after spraying, the amount of seed yield, the number of seeds per inflorescence, the number of inflorescences per m2, 1000 seeds weight, the amount of fresh forage, dry forage and the amount of produced protein were recorded. The results of two years combined analysis showed no significant difference among spraying treatments for all the mentioned characteristics, except the percent of larvae infested inflorescences after spraying. Contrary to spraying treatments, there were significant differences among mowing treatments for the percent of larvae infested inflorescences before spraying, the amount of seed yield, the number of inflorescences per m2, the amount of fresh forage, dry forage and the amount of produced protein. Considering the main objective of this experiment (obtaining the highest seed yield) and the high economic value of the clover seeds, the results showed that the mowing date of 16th March 2002 could be suggested as the best date. Also, the chemical control of P. trifolii had no significant effect on seed yield despite its effect on the population of the pest itself, so probably the chemical control of this pest in seed farms of Berseem clover has no economic justification in addition to its harmful environmental effects.

Forests cover about 5,200,000 hectares of the west of Iran, from which 500,000 hectares are located in Kurdistan province. One of the most important pests in the oak forests of this province is oak leaf roller moth, Tortrix viridana L. (Lep.: Tortricidae). This pest significantly damages the oak forest each year. Using pheromone trap is one of the suitable methods for monitoring of this pest. In this work, distribution and flight period of the pest were studied by pheromone traps during two years. Fifteen regions were trapped at the equal distances (40 km) from Kamyaran (south west of Kurdistan province) to Baneh (north west of Kurdistan province) to investigate the presence and distribution of this moth. Also, a region located between Sanandaj and Marivan was selected to study the flight period. Some traps were established in this region and checked every two days. Investigation of pest distribution showed that oak leaf roller moth was present all over the sites from Kamyaran to Baneh. Different populations of moth were trapped in all over the sites. The highest population was trapped in Colit region (mid-west of Kurdistan province). The study of flight period showed that first moths were trapped on May, 16th and the peak of the flight took place on May, 21st and finally the last moths were trapped on June, 24th. herefore, adults activated during 40 days; mating and oviposition occurred during this period. Incubation period lasted 9 months and activation of larvae was coincident with flashing of foliar buds.

Efficacy of temperature and exposure interval on the toxicity of Silico-Sec®, a diatomaceous earth formulation, was determined on 7-14 days old adults of Rhyzopertha dominica (F.) and Tribolium castaneum Herbst under laboratory conditions at 22, 27, 32 oC and 65 ± 5% R.H. Insects were exposed for 8-72 hours to diatomaceous earth at the rate of 10 g/m2 on a filter paper inside plastic Petri dishes separately. Then the initial mortality was counted and, to determine delayed mortality, live individuals were held for a week in clean Petri dishes without food at the same conditions of previous experiment. LT50 values of initial mortality for R. dominica were 21, 12 and 9 hours at 22, 27, 32 oC, respectively, and in the case of T. castaneum, they were 52, 27 and 18 hours at the same temperatures. The LT50 values indicated that R. dominica was more sensitive to Silico-Sec® than T. castaneum under identical conditions. Results indicated that the initial mortality of both species was significantly lower at 22 oC in comparison with 27 and 32 oC, and a direct relationship between temperature and exposure period was observed. Mortality percentage of both storage pests was higher after a week than initial mortality.Therefore, Silico-Sec® can be recommended as a structural treatment of stored grain facilities.

The biological effects on silkworm larvae fed on mulberry leaves contaminated with 0.5 and 1 mg/ml carbendazim were analyzed in different periods. The fungicide was sprayed on trees with 0, 1, 2, 4 and 8 days intervals before the first feeding of second instar larvae. Carbendazim decreased the larval weight and the highest reduction was 4.5% decrease compared to control. One mg/ml of fungicide used immediately after treatment caused a significant decrease in female cocoon characteristics such as cocoon weight, pupa weight and shell weight by 8.4, 8.5 and 7.8, respectively. The rate of hatching had also decreased in some treatments. Economical traits of male insects and the number of laid eggs by females were not affected. In total, the mean of cocoon shell percentage in both sexes did not have any difference with control. Feeding from the leaves contaminated with carbendazim residue did not have significant effects on larval mortality and utilization of the leaves sprayed by this fungicide two days after application is recommended.

The specimens of the tribe Syrphini, deposited at the Hayk Mirzayans Insect Museum, were examined and 30 species identified, of which one genus and three species are newly recorded from Iran and marked by an asterisk (*). Keys to the genera and species, as well as their distribution in Iran, are provided. The species are as follows:Dasysyrphus albostriatus (Fallen), D. eggeri (Schiner), Dideoides annandalei (Brunetti), Epistrophe eligans (Harris)*, E. euchroma (Kowarz), Episyrphus balteatus (De Geer), Ischiodon aegyptius (Wiedemann), I. scutellaris (Fabricius), Melangyna* cincta (Fallen)*, Meliscaeva cinctella (Zetterstedt), M. auricollis (Meigen), Eupeodes corollae (Fabricius), E. latifasciatus (Macquart), E. lunigar (Meigen), E. nuba (Wiedemann), Scaeva albomaculata (Macquart), S. dignota (Rondani), S. latimaculata (Brunetti), S. pyrastri (Linnaeus), S. rossica Kuznetsov, S. selenitica (Meigen), Sphaerophoria bengalensis Macquart, Sph. rueppelli (Wiedemann), Sph. scripta (Linnaeus), Syrphus ribesii (Linnaeus), S. torvus Osten Sacken, S. vitripennis Meigen, Xanthogramma laetum (Fabricius)*, X. maculipenne Mik and X. pedissequum (Harris).