JOURNAL OF ENTOMOLOGICAL RESEARCH
Year:2011 | Volume:3 | Issue:1 (9)|Papers Count:8

Cowpea weevil, Callosobruchus maculatus Pic., is one of the important pests of food industry in the world wide. The use of high temperatures or heat treatments is a very effective method for managing of the pests of stored products. In this study, the mortality of the pest in 5 constant temperatures, including 45, 50, 55 and 60oC each at durations of 5, 10, 15, 20 and 30 minutes on different growth stages (egg, 1-days larvae, 11-days larvae, pupae and adult C. maculates) was determined. The treated insects were kept at 30±1oC and relative humidity of 65±5%. the results showed that, The most sensitive and resistant stages were eggs and pupal stages, respectively. It also revealed that the minimum temperature to control eggs, 1-day old larvae, 11-day old larvae, pupal and adult stages were, 50, 50, 55, 55 and 55oC respectively. Since all stage of the insect are usually present in stored products, it is recommend to use 55oC heating at the duration of 15 minutes to control stored products infested with C. maculates.

Pomegranate fruit moth (PFM), Ectomyelois ceratoniae (Lep., Pyralidae), is one of the most important pests of pomegranate in Iran. The larvae of E. ceratoniae cause damage to pomegranate fruits. Several different methods including collecting and burning of infected fruits and biological control have been examined to control this pest, but these were not effective. One way that may prevent fruits infection is obstruction from laying eggs by the moth inside the fruit crown. In the present study, the effect of three types of fruit covers, including complete covering made by fabric net, crown covering with a plastic cap and crown covering with a cap made by fabric net on fruit infection rate were tested. The result showed that the mean infection rates were 9.50 and 2% for control and crown covering with a cap made by fabric net, respectively, so crown covering can reduce fruit damage by 78%. Comparison of flower and fruit drop, fruit cracking, cover stability and PFM infection indices between treatments indicated that using a cop made by fabric net on crown, in early May to early July, can be recommended for PFM control.

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Sugar cane stem borers are the most important pest of this crop in the world and Iran. Parasitism percent of the stem borer Sesamia nonagrioides Lefebvre by the wasp Telenomus busseolae Gahan was studied in Shooshtar, south of Iran in 2005-2006. The study was conducted in a Ratoon field in the first year and in a Plant field in the second year, both cultivated with variety of CP48-103.Numbers of parasitized and non-parasitized eggs were recorded weekly and percent parasitism was calculated by two methods of common and recruitment methods. Results showed a similar trend of the host and parasitoid populations in Ratoon field. However, the population of host’s eggs was in high in Plant field in the beginning of September, while the number of parasitized eggs was low. In addition, the parasitoid showed six period of activities during the agronomic year. According to these results the two methods were different, in percent parasitism eraluation. Meanwhile these results showed that recruitment was more reliable than the common method. The study also indicated that the parasitoid has an important effect on population dynamics of sugar cane stem bore in this area.

The effects of straight and reciprocal crossing on F1 hybrids were estimated on six quantitative traits viz., cocoon weight, shell weight, shell ratio, filament length, denier and renditta in the silkworm, Bombyx mori L. utilizing two bivoltine races and two multivoltine races namely NB4D2, C108, Nistari and Pure Mysore, respectively. In order to understand the genetics of cross breeding system between multivoltine and bivoltine races, a hybridization experiment was conducted by crossing females of multivoltine races (Pure Mysore and Nistari) with males of bivoltine races (C108 and NB4D2) and its reciprocals during 2009. The twelve straight and reciprocal hybrids were reared under standard laboratory condition. The data of the hybrids was analysed for the estimation of six economical traits to study the crossing effects, between the hybrids. The straight and reciprocal crossing of C108 × NB4D2 has shown maximum cocoon weight (0.37 gr) whereas PM´Nistari has recorded minimum cocoon weight (0.2 gr) among the hybrids. Superiority of strait crosses between multivoltine and bivoltine races only have been shown for denier trait in PM´NB4D2 hybrid. In bivoltine´multivoltine hybrids, characters such as cocoon weight, shell weight, filament length and denier showed high significant difference.

In many entomological studies, a smaller sample is taken than a statistician would advise.Clearly, such experiments would often fail to detect any significant effects, resulting in a complete waste of time and money. The present paper introduces statistical power of a test and its importance in determining the minimum sample size required for detecting significant effects. A number of experiments fail simply because the issues of statistical power are not confronted with at the planning stage. A fundamental question that is needed to address at the planning stage concerns the number of samples required to test the hypothesis of interest. The answer depends on the variance of response variable, the size of difference in the response variable that would be detectable as significant, the risk of a Type I error and the risk of a Type II error. Here using R language of statistical computing, the specific methods of the calculation of optimum sample size for laboratory and field studies are presented for two common scenarios.

Red palm weevil (RPW), Rhynchophorus ferrugineus Oliv. is one of the most important pests of palms in Asia, North Africa and Europe. At present, it is an internal quarantine pest in Saravan region (Sistan & Balouchistan province, Iran). Several experiments on the effect of the plant baits, shape and place of trap on the attracting and trapping of RPW have been carried out in infested date palm groves in Saravan region, during 2007-2008. The results showed that the traps baited with date palm core and aggregation pheromone significantly attracted more beetles of RPW in comparison with other baits include date fruit, apple fruit and banana stem. This subject clearly showed the high synergistic effect of date palm core on the aggregation pheromone of RPW.Covered traps with date palm stem tissue attracted significantly more number of beetles in comparison to traps without cover. The effect of trap place on the attraction of RPW showed that there was not any significant difference in the mean of catches of RPW by traps that had been placed in different trees and metal beam, Because all treatments were equally attractive to RPW.Application of date palm core with aggregation pheromone and covering trap with date palm stem tissue increased the efficiency of RPW pheromone traps.

The full text of this article is the Persian language, please for the view full text, refer to Persian Please click here to view the full text of this article