Browsing by Author "Qayyum, Abdul"

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Demographic Parameters of Lipaphis Erysimi (Hemiptera: Aphididae) on Different Cultivars of Brassica Vegetables
(Oxford Univ Press inc, 2018) Qayyum, Abdul; Aziz, Muhammad Asif; Iftikhar, Ayesha; Hafeez, Faisal; Atlihan, Remzi
Demographic parameters of the turnip aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae), which is a serious pest of Brassica crops worldwide, were evaluated on five major Brassica vegetables (three varieties of Brassica oieraceae (Linnaeus) (Brassicaceae Brassicales); kohlrabi, cabbage and ornamental cabbage, and two subspecies of Brassica rapa (Linnaeus) (Brassicaceae Brassicales), Chinese cabbage and bak choi). The study was carried out under laboratory conditions at 25 +/- 1 degrees C, 70 +/- 5% RH and 16:8 (L:D) h. Preadult developmental time, survival rate, female longevity, reproduction, and life table parameters were evaluated according to the age-stage specific life table method. The highest population growth parameters, i.e., net reproductive rate (R-0), intrinsic rate of increase (r), and finrte rate of increase (lambda) were recorded on kohlrabi (R-0 = 30.45 offspring, r= 0.2174 d(-1),lambda= 1.2429 d(-1)) These parameters were the lowest on Chinese cabbage (R-0 = 13.00 offspring, r = 0.1503 d(-1), and lambda = 1.1621 d(-1)) and bak choi (R-0 = 16.30 offspring, r = 0.1614 d(-1), lambda = 1.1752 d(-1)). The results attained from population growth parameters, together with population projection estimation based on the age-stage, two-sex life table theory, indicated that both Chinese cabbage and bak choi were less suitable hosts for turnip aphids and should be considered as a possible source for developing resistance in breeding programs and integrated pest management strategies.
Neogene Kinematics of the Potwar Plateau and the Salt Range, Nw Himalayan Front: a Paleostress Inversion and Ams Study
(Taylor & Francis inc, 2022) Qayyum, Abdul; Poesse, Jorik Willem; Kaymakci, Nuretdin; Langereis, Cornelis G.; Gulyuz, Erhan; Ahsan, Naveed
We provide new kinematic data from the Potwar Plateau (Pakistan) to evaluate the tectonic evolution of the region during the Neogene. The plateau is bound by two major strike-slip faults in the west and the east, accommodating its southwards translation. We have recognized two Neogene deformation phases in the plateau, based on paleostress inversion and Anisotropy of Magnetic Susceptibility (AMS) tensors. The first phase lasted until the early Pliocene and was characterized by vertical minor stress and N-S compression, implying thrust tectonics. The second deformation phase is characterized by a near-vertical intermediate principal stress and near-horizontal major and minor stresses, interpreted to be associated with strike-slip tectonics since the late Pliocene. K-int vectors from 21 sites are relatively compatible with the major principal stress orientations (sigma(1)) and indicate two distinct domains. This is possibly because K-min orientations are related to compaction, whereas K-int orientations were always parallel to tectonic shortening and hence compression direction during both strike-slip (post-late Pliocene) and thrusting (pre-late Pliocene) phases. These phases are characterized by swapping of (sigma(2)) and (sigma(3)) orientations while (sigma(1)) maintained its orientation. The most prominent change occurs at the western part of the Potwar Plateau, where major principal stress directions (sigma(1)) and K-int axes fan out south-westwards. The eastern domain is dominated by NE-SW trending folds and thrust faults, which are absent in the western domain. These structural features are interpreted to be the result of the distribution of deposits of the Neoproterozoic Salt Range Formation as a substratum below the Potwar Plateau. The Salt Range Formation is very thick and widespread in the west area and almost absent in the east. This factor led to unconstrained southwards gliding of the Potwar Plateau over the salt deposits in the west as opposed to frictional sliding and substantial internal deformation in the east.