PLANT PEST RESEARCH
Year:2021 | Volume:10 | Issue:4|Papers Count:7

Habrobracon hebetor Say, is one of the most important larval parasitoids of many lepidopteran pests, particularly the family Noctuidae. In this study, the lethal and sub-lethal effects of chromafenozide, pyridalyl and thiodicarb, as insecticides, were investigated on this parasitoid under laboratory conditions. Bioassay tests on adults were conducted based on contact method and sub-lethal effects were done based on demographic toxicology. According to bioassay tests, estimated LC30 values for chromafenozide and thiodicarb were 126. 43 and 54. 24 mg a. i. /L, respectively. Since even with the application of three times more than that of the field concentration of pyridalyl (2250 mg a. i. /L), maximum mortality percentage of insects was 19%; LC30 value was not estimated for this insecticide. In order to assess sub-lethal effects of insecticides, female wasps were exposed LC30 values of chromafenozide and thiodicard and the field concentration of pyridalyl (750 mg a. i. /L). According to sub-lethal tests, insecticide treatments significantly affected duration of life different, fecundity and life table parameters. The intrinsic (r) and finite (λ ) rates of increase were significantly lower in insecticide treatments than that of control. Overall, results showed that thiodicarb had the highest toxicity effect on H. hebetor, while pyridalyl and chromafenozide had less adverse effects on this parasitoid. Following field experiments and subject to confirmation of the results of this study, it is possible to use pyridalil and chromafenozide in integrated pest management programs.

Eatoniana gonabadensis (Ahmadi, Hajiqanbar and Saboori, 2012), Charletonia saboorii Karimi Iravanlou, Kamali and Talebi, 2002 and Eutrombidium sorbasiensis Mayoral and Barranco, 2004 were collected and identified ectoparasitic on Acrididae and Tettigoniidae (Orthoptera) from Dehbar village, Mashhad city, Khorasan Razavi province in 2019. Eatoniana gonabadensis and C. saboorii belong to the subfamily Erythraeinae Robineau-Desvoidy, 1828 and Callidosomatinae Southcott, 1957 (Acari: Prostigmata: Erythraeidae), respectively. Eutrombidium sorbasiensis belongs to the family Microtrombidiidae Thor, 1935 and subfamily Eutrombidiinae Thor, 1935. Eatoniana gonabadensis has been described before from Gonabad city, Khorasan Razavi province ectoparasitic on Aphis craccivora Koch, 1854 (Hemiptera: Aphididae) and Dociostaurus cf. tartarus Stshelkanovtzev, 1921 (Orthoptera: Acrididae) and it is the second record from this province. Also, this species was recorded ectoparasitic on an unidentified grasshopper (Tettigoniidae) from Pol-e Sefid city, Mazandaran province, Iran. Charletonia saboorii has been described before from Varamin region ectoparasitic on Heteracris littoralis (Rambur, 1838) (Orthoptera: Acrididae). In the present paper, the new morphological data for E. gonabadensis (eight normal setae on Ge I; two pairs of setae between Cx II and III; fn Ta I– III 26-23-23; anterior hypostomalae (aHy) present; fPp: 0-B-B-BBB2-4Nω  z) and new metric data for C. saboorii are presented.

Trichogramma evanescens Westwood is an important biological control agent of lepidopteran pests and is widely distributed throughout Iran. In the current study, parasitism rate of T. evenescens on different egg ages of the Anagasta= Ephestia kuehniella Zeller (1, 2, 3 and 4-day-old) was studied at 25± 1º C, 55± 5% RH and 16: 8 h L: D photoperiod. The results obtained showed a significant effect on parasitism rate. The highest and the lowest values of net parasitism rate (C0) were 67. 69 hosts and 15. 92 hosts for 1 and 4-day-old eggs, respectively. The transformation rate of host population to parasitoid offspring (QP) was equal to 1 at all egg ages. The values of stable parasitism rate (ψ ) decreased from 0. 412 to 0. 266 (host/parasitoid) with increasing host age from 1 to 4 day. Finite parasitism rate (was significantly affected by different egg ages and the highest (0. 583 day Abstract-1 ) and lowest (0. 337 day-1 ) values were recorded for 1 and 4-days-old eggs, respectively. The results of the current study indicated that parasitism of T. evanescens was strongly affected by different egg ages of A. kuehniella. This finding provide helpful information for mass rearing of T. evanescens.

n the present study, lethal and sublethal effects of essential oils of Artemisia khorassanica Podi, Carum carvi L. and Piper nigrum L. was assessed on number of parameters of Phthorimaea operculella (Zeller). The lethal concentrations (LC50) of essential oils were determined on the adults. Sublethal concentration (LC20) of essentials decreased the amount of life expectancy (ex), and showed different changes on the survival rate (lx) and reproductive value (vx) in comparison with the control. A. khorassanica essential oil in comparison with two the other essential oils decreased the population growth parameters such as gross reproduction rate (GRR), net reproduction rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ ) and increased the mean generation time (T) significantly. The essential oil of A. khorassanica had the most effective on biological parameters such as larval duration, immature stages, female longevity, the fecundity and fertility. The essential oil of A. khorassanica decreased the amounts of pupal protein (489. 2 ± 20. 86 µ g/pupa), lipid (812. 40 ± 48. 70 μ g/pupa) and glycogen (96. 4 ± 5. 51 µ g/pupa) of pupae compared with the control (606. 8 ± 28. 38, 941. 80 ± 54. 97 and 150. 40 ± 15. 09 µ g/pupa, respectively). Chemical composition analysis of the essential oils showed that camphor and 1, 8-cineol in A. khorassanica and 2-methyl-3-phenyle propane in C. carvi and P. nigrum had the most amount. Considering the lethal and sublethal effects of essential oils, performing additional research achieving their application in the management of pest is recommended.

Predatory mite Amblyseius swirskii Athias-Henriot is one of the most important species of Phytoseiidae. In the current study, the effects of feeding on different preys including two-spotted spider mite Tetranychus urticae Koch, cereal mite Tyrophagus putrescentiae (Schrank), silverleaf whitefly Bemisia tabaci (Gennadius); together with integrated treatments of these preys including spider mite+cereal mite, spider mite+whitefly, cereal mite+whitefly and spider mite+cereal mite+whitefly on the biological charactristics of adult females of this predator (predation, fecundity and survivorship) were investigated after seven days storage at 10 ° C. Larva and adult female with 72. 34 and 11. 76 % mortality had the highest and lowest susceptibility of this predator to temperature of 10 ° C, respectively. The highest feeding of predatory mite after cold storage was observed on the larva and protonymph of T. urticae (91. 63 prey). The lowest feeding was recorded on eggs of cereal mite (10. 18 prey). Total fecundity of the predatory mite was significantly affected by different prey; the highest (5. 13 egg) and lowest (1. 55 egg) values of this parameter were recorded when the predatory mite fed on “ spider mite+cereal mite+whitefly” and “ cereal mite” , respectively. In the view point of mortality, the highest percentage was recorded in the predatory mites that reared on the cereal mite. According to the results obtained, integrated treatment of “ spider mite+cereal mite+whitefly” was the most suitable treatment for the storage of A. swirskii at cold conditions than other treatments tested.

Peach twig borer, Anarsia lineatella Zeller, as one of the most important pests of stone fruit trees in Iran and worldwide, causes severe damage annually. In this research, the pest seasonal dynamics on early (Prunus persicae var. keres), moderate (Prunus persicae var. zafarani) and late (Prunus persicae var. sibi) ripening peach cultivars was studied by using pheromone traps in three orchards (1 ha), in Mazandaran province during 2012-2013. Four pheromone traps were placed at 1. 5-2 m height per orchard for weekly monitoring the adult moths. To determine the larval infestation, 10 trees (per orchard) were selected and 40 new shoots and 100 fruits (from each tree) were randomly inspected per week. The results indicated that A. lineatella had 3-4 generations and overwintered as 1 st nd and 2 instar larvae inside terminal parts of infested shoots. The first moths were trapped in mid-April with maximum population appeared three weeks later, coinciding with main flushing stage of the trees. The three main peaks of the moths were observed in April, June and July, which almost concur with the huge flushing stage of the trees. The 1 st generation larvae generally attacked the new shoots. Feeding activity of second generation of pest was very important for moderate and late ripening cultivars. Fruit damage on moderate and late ripening cultivars was determined around 4. 2 and 5. 5 percent, respectively. In conclusion, under high density of 2 nd rd and 3 generations, severe damage on the fruits may be expected and consequently control recommended.

Camelina is an annual oilseed plant of the Brassicaceae. Resistance to some diseases and pests of other members of Brassicaceae plants is one of the important features of Camelina. In the experimental sowing of this plant in Ahvaz in the cropping year 2018-2019, while the seeds were still immature, silicles shattering was observed in some camelina plants in experimental plots. After careful observation, it was discovered that some ants were cutting off the plant silicles and transferring them to their nests. Damages by these ants to Camelina plants were not limited to availibility of plants on the farm. These damages were also observed at the time of harvesting and counting of yield components. The ant was identified as Messor ebeninus Santschi, 1927 (Myrmicinae: Formicidae). This species has previously been reported from northern and southwestern of Iran. Collected specimens are preserved in the insects and mites collection, at the Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University of Ahvaz. This is the first report of insects damage to Camelina in Iran.