Organic Soils Control Beetle Survival While Competitors Limit Aphid Population Growth

Nonlinear stochastic modeling of aphid population growth.

This paper develops a stochastic population size model for the black-margined pecan aphid. Prajneshu [Prajneshu, A nonlinear statistical model for aphid population growth. J. Indian Soc. Agric. Statist. 51 (1998), p. 73] proposes a novel nonlinear deterministic model for aphid abundance. The per capita death rate in his model is proportional to the cumulative population size, and the solution i...

//colorado Potato Beetle: Organic Control Options

Nonfumigant Nematicides for Control of Root-knot Nematode to Protect Carrot Root Growth in Organic Soils.

Greenhouse tests were conducted to determine the effects of two kinds of Meloidogyne hapla inoculum on the growth and quality of carrot roots, and the protection afforded in each case by nonfumigant nematicides in organic soils. For all treatments the percentage of carrots damaged was greater with larvae alone as inoculum than with larvae and eggs, indicating that most of the damage occurs earl...

Ant semiochemicals limit apterous aphid dispersal.

Some organisms can manipulate the nervous systems of others or alter their physiology in order to obtain benefit. Ants are known to limit alate aphid dispersal by physically removing wings and also through chemical manipulation of the alate developmental pathway. This results in reduced dispersal and higher local densities of aphids, which benefit ants in terms of increased honeydew and prey av...

Intrinsic and extrinsic determinants of mountain pine beetle population growth

1 Mountain pine beetle Dendroctonus ponderosae populations have large, economically significant outbreaks. Density dependence and environmental variability are expected to have important effects on their dynamics. We analysed time series data from an outbreak in the 1930s to determine the relative importance of population density and environmental variability on local population growth rates. 2...