Persian Journal of Acarology

Abstract Pesticide-resistant populations of the two-spotted spider mite, Tetranychus urticae Koch, have been reported in many countries. This problem has led to the search for alternative control methods. One of these alternative strategies is aqueous ozone. During a series of preliminary test, the effect of different concentrations of aqueous ozone on mortality of T. urticae on pepper (Capsicum annuum L.) was evaluated in greenhouse conditions at 25 ± 2 °C; 50 ± 5% RH and 16:8 (L:D) photoperiod. Then efficacy of ozone to control the pest was evaluated in different experimental conditions including three exposure times (5, 10 and 15 seconds), different time of spraying (8 am, 2 pm and 8 pm), and different ages of the host plant (4, 8 and 12 weeks old). Each experiment was carried out in a randomized complete design with six replications. Based on the screening tests, ozone concentration of 43 g/m³ was found to give efficient results in terms of mortality rates of the mites and morphological traits of the host plant. The mortality rate of the mites increased with increasing exposure time. Although the interaction effect between ozone concentration and exposure time was significant, in other experiments, no significant difference in the mortality percentage of the mite among either times of application, or ages of the host plant was found. In none of these experiments, no symptom of injury to the host plant foliage such as chlorosis, necrosis, yellowing or malformation was observed after aqueous ozone spraying. Based on these results, aqueous ozone at a specific concentration and conditions can reduce the population density of T. urticae without any visible damage on the pepper foliage. However, more research needs to be done before ozonated water can be deployed commercially as a pesticide.

Abstract The role of rodents in transmission of different parasitic infections, has been well documented. The objective of this study was to determine the relationship between capturing season and rodent habitat with ectoparasites prevalence in the murin rodents from northeast of Iran. Furthermore the host species-related effects on ectoparasitic prevalence were studied.A field survey of ectoparasites was carried out in 20 localities from April 2013 to April 2015. A total of 74 murin rodent were captured: 17.56% Apodemus witherbeyi, 35.13% Mus musculus, 21.62% Nesokia indica and 25.67% Rattus noorvegicus. A total of 413 ectoparasites were collected as follows: 19.85% fleas, 24.45% ticks, 39.70% mites and 16.22% lice. The most infested rodent was R. norvegicus (P= 89.47%) and the most common ectoparasite was mites. The highest prevalence was observed in summer (P= 31.57%) and ticks were the most common ectoparasite for this season. Behesht Reza and Railway station were the highest infested areas with P= 12.28%. Prevalence of overall ectoparasites (P= 74.32%) was higher in Behest Reza cemetery and Railway station compared to the other localities. Seasonal changes in the prevalence of some ectoparasites paralleled those in the relative abundance of their hosts. Furthermore, the prevalence of some ectoparasites showed differences related to the locality of their hosts. There were significant differences between the prevalence of each of ectoparasitic group in all four species.These relationships are useful in understanding the role of arthropod vectors as well as their reservoirs in the transmission of diseases in humans and other animals.