Showing 4 results for J. Khajehali
M . Latifian, H. Seyedoleslami, J. Khajehali,
Volume 8, Issue 3 (fall 2004)
Abstract
Populations of Arboridia kermanshah Dlabola is increasing in Isfahan vineyards. In this study, some morphological characteristics of the immature stages, over wintering sites, number of generations per year, and seasonal population fluctuations of this pest were studied in vineyards in Isfahan Province. Eggs showed apparently four distinct embryonic developmental stages. At 25.8 ±2˚C, development of eggs was completed in 10.9 ± 0.7 days. There were five nymphal developmental stages. Nymphal stages can be distinguished with wing pad development and width of head capsule and width of pronotum. The grape leafhopper overwintered as adults under leaves and crop residues. Rearing studies showed that the grape leafhopper had three generations per year, each lasting 33.9±0.6 (without overwintering period), 46.3±0.7 and 37.3±0.6 days, respectively. Seasonal monitoring of adults, nymphs and eggs showed three or four overlapping periods of activity in the field. Four periods of activities of adults were recorded through season from early May – mid June, mid June – mid July, mid July - late August and early September – mid October.
M. Latifian, H. Seyedoleslami, J. Khajehali,
Volume 9, Issue 2 (summer 2005)
Abstract
Some bioecological aspects of grape leafhopper, Arboridia kermanshah Dlabola, including: the egg distribution under the leaf surface, eggs and nymphs spatial distribution on the vine arms, the adult distribution on three strata of the vine canopy, the adult diel activities and the geographical distribution of this species in Isfahan province were studied. Samplings were done in the 1997. The egg distribution under the leaf surface was determined by repeated sampling during the season and the egg density was estimated on three regions such as the main and secondary vein, the leaf surface margins and others. Eggs and nymphs spatial distribution along the vine arms were studied weekly for six weeks by sampling an arm of five vines during the second generation, the leafhopper population was the highest. The adult spatial distribution on the vine canopy was determined by sampling three strata of the vine canopy using the D-vac apparatus. Diel activities were studied by sweeping nets fifty times per vineyard at the two hour intervals from 8 a.m. to 20 p.m. Temperature and the relative humidity were also measured in the shade once per hour. The presence and the abundance of this species in 87 vineyards in the different climatic conditions were studied by a sweeping net. The leaf margin and around of the secondary vein were preferred for the oviposition of the leafhopper. Adults, nymphs and eggs were more abundant in the middle strata of the vine canopy than others. The mean pattern of the daily activity of the adult indicated one peak at 8 a.m. and the other one at 20 p.m. Maximum temperature thereshold for the adult activities was 28º C. The study of the grape leafhopper distribution in isfahan province indicated that this species was distributed in the most vineyards, but was highly abundant in more humid conditions.
M. Latifian, H. Seyedoleslami, J. Khajehali,
Volume 9, Issue 3 (fall 2005)
Abstract
In 1997, in two vineyards of Isfahan university of technology and Zobeahan in Isfahan, the density fluctuations of Arboridia kermanshah Dlabola and their injury symptoms were studied. In each vineyard three leaves of each of ten randomly selected vines were sampled weekly. Nymphs in different instars were counted directly and rate of injury symptom (leaf discoloration) was determined with planimeter. Special cages were used to determine rate of injury symptom for each nymphal instar in comparison to each other. Rate of injury symptoms and nymphal density indicated two peaks through growing season until harvest. Tolerance threshold for A. kermanshah nymphs was determined 80 first instar nymphal days or presence of 11-12 first instar nymphs and feeding for seven days. With increase of nymph densities, damage symptom increased rapidly.
A. Mazaheri, B. Hatami, J. Khajehali, S. E. Sadeghi,
Volume 11, Issue 41 (fall 2007)
Abstract
Sarta longhorned beetle, Aeolesthes sarta, is one of the most destructive wood borer pests of fruit and shade trees in Iran. In this research, the reproductive parameters were studied under laboratory conditions. Fifteen pairs of newly developed adults (1-2 days after emergence from overwintering sites) were caged separately on 15 logs of Ulmus carpinifolia and fertility table was made using this data. The results showed that 3.9±0.2 days after emergence, females began to oviposit for 16.6±0.6 days, as oviposition period. Mean number of laid eggs was 122.6±17.5 per female. The mean longevity of male and female was 26±0.6 and 29.4±0.4 days, respectively. Females had no mortality during oviposition period, so gross reproductive rate (GRR) and net reproductive rate (R0) (famale/female/generation) were equal (61.6±8.7). Intrinsic rate of increase (rm), mean generation time (T) and doubling time of the population (t) were 0.0067±0.24-5 famale/female/day, 612.5±0.4 and 102.7±3.6 days, respectively. The finite rate of increase (λ) (female/female/day) was 1.006±0.24-5. Intrinsic rate of increase (rm) was very low (0.00672), because of longer lifetime of females (mean 602 days), low longevity during reproductive period (maximum 22 days) and long mean generation time (612.5 days).
