the toxicity of imidacloprid and pirimicarb for all stages of the melon aphid, aphis gossypii glover, were investigated under laboratory conditions (25 ± 1 oc, 65 ± 5% r.h. and a photoperiod of 16:8 (l: d) h.) using a leaf dipping method. these pesticides were very toxic for first instar nymphs of a. gossypii with lc50 values of 17 and 220.2 ppm for imidacloprid and pirimicarb, respectively. fo...

the beet armyworm, spodoptera exigua, is one of the most important pests of sugar beet in iran. the aim of this study was to determine the effect of water and nitrogen treatments of sugar beet planton developmental time and fecundity life table parameters of the pest. an experiment was carried out under laboratory conditions (25±2oc, 70±5% r.h. and 12l: 12d) on larvae reared on sugar beet leave...

The net reproductive rate R0 measures the expected lifetime reproductive output of an individual, and plays an important role in demography, ecology, evolution, and epidemiology. Well-established methods exist to calculate it from age- or stage-classified demographic data. As an expectation, R0 provides no information on variability; empirical measurements of lifetime reproduction universally s...

1. Second derivatives of the population growth rate measure the curvature of its response to demographic, physiological or environmental parameters. The second derivatives quantify the response of sensitivity results to perturbations, provide a classification of types of selection and provide one way to calculate sensitivities of the stochastic growth rate. 2. Using matrix calculus, we derive t...

life table of almond moth, cadra cautella walker was studied on four main dry and semi-dry date palm varieties (deyri, zahedi, piarom, and rabbi) of iran under laboratory conditions. data were analyzed based on the age-stage, two-sex life table theory. duration of total preadult stages was 42.54, 45.79, 51.48 and 50.41 days on deyri, zahedi, piarom, and rabbi, respectively. the highest fecundit...

The effectiveness of inundative releases of the parasitoid Encarsia formosa for control of Bemisia argentifolii on poinsettia was determined in replicated experimental greenhouses. We evaluated two release rates of E. formosa: a low release rate (1 wasp/plant/week, released in two greenhouses, in spring 1995) and a high release rate (3 wasps/plant/week, released in two greenhouses, in fall 1993...

Aspects of Biosteres arisanus (Sonan) (= Opius oophilus Fullaway) (Hymenoptera: Braconidae) development on the oriental fruit fly, Bactrocera (= Dacus) dorsalis (Hendel), were investigated to facilitate mass production in the insectary. Life table statistics were generated for cohorts of B. arisanus females. Overlap in the emergence of fruit flies and parasitoids necessitated a procedure for se...

The beet armyworm, Spodoptera exigua, is one of the most important pests of sugar beet in Iran. The aim of this study was to determine the effect of water and nitrogen treatments of sugar beet planton developmental time and fecundity life table parameters of the pest. An experiment was carried out under laboratory conditions (25±2oC, 70±5% R.H. and 12L: 12D) on larvae reared...

The beet armyworm, Spodoptera exigua, is one of the most important pests of sugar beet in Iran. The aim of this study was to determine the effect of water and nitrogen treatments of sugar beet planton developmental time and fecundity life table parameters of the pest. An experiment was carried out under laboratory conditions (25±2oC, 70±5% R.H. and 12L: 12D) on larvae reared...

The beet armyworm, Spodoptera exigua, is one of the most important pests of sugar beet in Iran. The aim of this study was to determine the effect of water and nitrogen treatments of sugar beet planton developmental time and fecundity life table parameters of the pest. An experiment was carried out under laboratory conditions (25±2oC, 70±5% R.H. and 12L: 12D) on larvae reared...