Acyrthosiphon Pisum (Harris) Numeric Dynamics In Alfalfa Field

In this paper, population dynamics of Acyrthosiphon pisum (Harris) and its dominant natural enemies, life table parameters of Acyrthosiphon pisum (Harris), and predatory function of Hippodamia vartegata (Goeze) to Acyrthosiphon pisum (Harris) were researched. The results were as follows:1. Investigation of numeric dynamics of Acyrthosiphon pisum (Harris) and its dominant natural enemiesAcyrthosiphon pisum (Harris) took place in the first ten days of May, reached it's peak at the beginning of July. Then the population sharp decreased, vanished in middle of August. There was different quantity of Acyrthosiphon pisum (Harris) in ten alfalfa varieties.Numeric dynamics of dominant nature enemies of Acyrthosiphon pisum (Harris) were investigated, such as Chrysopa formosa Brauer, Hippodamia (Adonis) variegate (Goeze), Nabis stem ferus Hsiao and spider. There was one peak in increasing of Chrysopa formosa Brauer, Hippodamia (Adonis) variegate (Goeze) and Nabis stem ferus Hsiao. It's population reached peak in middle of July. After that population decreased gradually, vanished in middle of August. The appearance of peak late 10 days compared with Acyrthosiphon pisum (Harris).The ebb and flow dynamic of spider population was double peak type. It's population reached peak respectively at the beginning of July and late July.2. Studies on experimental population life table of Acyrthosiphon pisum (Harris)The present paper deals with the effects of temperature on the development, survival and reproduction of Acyrthosiphon pisum (Harris) at six different temperatures (12℃,15℃,18℃, 21℃,24℃and 27℃)and relative humiditie(80% RH). The life tables were constructed and life parametrers were compared at 6 treatments. At 24℃and 80% RH the intrinsic rate of natural increase was the highest (rm =0. 28)and the finite rate of increase(λ) was determined to be 1.32/d. The mean generation time(T) was calculated to be 10.09 days and the net reproductive rate (R0)to be 17.03. The relationship between the temperatures and the intrinsic rates of natural increase showed a parabolic curve within the temperature range tested. 3.The Predatory Function of Hippodamia vartegata (Goeze) to Acyrthosiphon pisum (Harris)The predatory function of the adults and larva of Hippodamia (Adonis) variegate (Goeze) to Acyrthosiphon pisum (Harris) were tested in lab. The results showed that the adults and 4th-larva of Hippodamia (Adonis) variegate (Goeze) had a good predatory function to...