Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) is a cosmopolitan species and the main pest of fennel in northeastern Brazil. Understanding the relationship between temperature variations and the population growth rates of H. foeniculi is essential to predict the population dynamics of this aphid in the fennel crop. The aim of this study was to measure the effect of constant temperature ...

In infectious disease epidemiology the basic reproductive ratio, R0, is defined as the average number of new infections caused by a single infected individual in a fully susceptible population. Many models describing competition for hosts between non-interacting pathogen strains in an infinite population lead to the conclusion that selection favors invasion of new strains if and only if they ha...

It is common practice in disease modeling studies to characterize groups or subgroups using population-average parameters, most importantly the basic reproductive number, R0. This approach overlooks variation at the individual level, which is caused by many factors. In this paper we show evidence of significant individual-level variation in transmission patterns for several diseases, and discus...

The use of computer algebra software has many applications in diverse fields like epidemiology. This work pretends to show how computer algebra software applications for symbolic computation have a very promissory future in mathematical epidemiology with a concrete problem of this kind. In this case; the basic reproductive rate, corresponding to the propagation of a certain disease inside a cir...

The brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera: Delphacidae) is one of the most destructive rice pests in Asia. microbial metabolite decoyinine (DCY) has been extracted from Streptomyces hygroscopicus. Recent studies have suggested that treating seeds with DCY could improve growth and yield rice. To further assess effects priming different varieties on seedling resistance again...

ABSTRACT Disease transmission is difficult to model because most vectors and hosts have different generation times. Chagas disease is such a situation, where insect vectors have 1-2 generations annually and mammalian hosts, including humans, can live for decades. The hemataphagous triatominae vectors (Hemiptera: Reduviidae) of the causative parasite Trypanosoma cruzi (Kinetoplastida: Trypanosom...

The predatory mite Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) is currently used as an efficient biological control agent of thrips, whiteflies and spider mites, which are economically damaging pests ornamental plants vegetable crops grown in greenhouses fields worldwide. Currently, the effects relative humidity (RH) water availability on optimal growth A. unknown. Here, we test ...

One key issue for theory in stream ecology is how much stream flow can be changed while still maintaining an intact stream ecology, instream flow needs (IFNs); the study of determining IFNs is challenging due to the complex and dynamic nature of the interaction between the stream environment and the biological community. We develop a process-oriented benthic-drift model that links changes in th...

Gerbera (Gerbera jamesonii Bolus and Hook,) is an ornamental Asteraceae of great commercial value, and pests can affect adversely its cultivation. More than 20 species of arthropods cause economic damage on gerbera, among them the two spotted mite, Tetranychus urticae Koch, 1836 (Acari: Tetranychidae), considered a key pest for this and other ornamental plants. In this work, some life-cycle asp...

Predator–prey interactions play major and direct roles in the structuring of zooplankton communities. Asplanchna usually predates ciliates, rotifers, cladocerans and sometimes even copepods, its predation may drive not only the ecological, but also the evolutionary dynamics of prey populations. In the present study, the life-table demography and the population growth of Asplanchna brightwelli w...