Yaws is targeted for eradication by 2020. The mainstay of the eradication strategy is mass treatment followed by case finding. Modeling has been used to inform programmatic requirements for other neglected tropical diseases and could provide insights into yaws eradication. We developed a model of yaws transmission varying the coverage and number of rounds of treatment. The estimated number of c...

If the demographic parameters in a matrix model for the dynamics of a structured population are dependent on a parameter u, then the population growth rate r = r(u) and the net reproductive number R0 = R0(u) are functions of u. For a general matrix model, we show that r and R0 share critical values and extrema at values u = u∗ for which r(u∗) = R0(u∗) = 1. This allows us to re-interpret, in ter...

Spodoptera exigua (Lepidoptera: Noctuidae) is one of the major pests of many crops in Pakistan. Effectiveness of different insecticides was evaluated against field populations of 2 instar larvae of S. exigua under laboratory conditions because in lepidopterous pests resistance is developed in 3 instars. Bioassays were performed through leaf dip method to evaluate the doseand time-mortality resp...

We studied the mechanism of cold acclimation of Jerusalem artichoke (Helianthus tuberosus L.) tubers with special reference to the role of the cell wall. During the cold-acclimation process from September to January, the freezing tolerance of tubers increased from -2.8 degrees C to -8.4 degrees C (LT50). By contrast, the isolated protoplasts constitutively showed a consistent high level of free...

Fumigant toxicity and sublethal effects of essential oils from Artemisia khorassanica Podl. and Artemisia sieberi Bess were investigated against adults of Sitotroga cerealella Olivier. To assess the sublethal effects, adult moths were exposed to the LC30 of each essential oil, and life table parameters of the surviving S. cerealella were studied. Higher fumigant toxicity of A. khorassanica (LC5...

When alfalfa (Medicago sativa L. cv Apica) plants grown at room temperature are transferred to 2 degrees C, the temperature at which 50% of the plants fail to survive (LT50) decreases from -6 to -14 degrees C during the first 2 weeks but then increases to -9 degrees C during the subsequent 2 weeks. However, when plants are kept for 2 weeks at 2 degrees C and then transferred to -2 degrees C for...

The repellency and toxicity of mint oil to American, Periplaneta americana (L.), and German, Blattella germanica (L.), cockroaches were evaluated in a series of laboratory experiments. In topical application experiments, mint oil was toxic to both species with toxicities (LD50s) of 2.57 (1.98– 4.20) in 10 l and 3.83 (2.35–7.34)% in 2 l for American and German cockroaches, respectively. In conti...

Spilarctia obliqua nucleopolyhedrosis virus (SoNPV) has been found effective against S. obliqua (Walker) as well as Porthesia xanthorrhoea Kollar. LC50 concentration of S. obliqua SoNPV against S. obliqua and P. xanthorrhoea was 2.5 x 10(4) and 3.7 x 10(4) POBs/ml, respectively. LT50 of SoNPV against S. obliqua was 5.73 days, while it was 6.98 days for P. xanthorrhoea. Cross infectivity of SoNP...