Population Dynamics And Control Strategies Of Marucatestulalis Geyer And Prodenialitura (Fabricius) In The Cowpea Field

Marucatestulalis Geyer and Spodoptera litura(Fabricius)are the pest that mainly cause damage of cowpea.To find out the occurring regulation about the two pests,the research was done in the Liuyang.city.This paper concerned on the population dynamics of Marucatestulalis Geyer and Spodoptera litura(Fabricius).The major results from these studies are summarized as follows:1.6～7 generations of Marucatestulalis Geyer occurred during one year in Liuyang and the peak of damage appeared during the June,July and August.5～6 generations of Spodoptera litura(Fabricius) occurred and the peak of damage appeared during July,August and September.2.The peak of damage caused by Marucatestulalis Geyer was on Jun.11^th when cowpea sowed in spring and was on Aug.29^th when cowpea sowed in summer,the time of May 22^th and Jun.16^th was peak period of damage that caused to cowpea that sowed in spring by Spodoptera litura(Fabricius),the time of Aug.4^th and Sept.18^th. was peak period of damage that caused to cowpea that sowed in summer by Spodoptera litura(Fabricius).3.Marucatestulalis Geyer like to oviposit on the flowers,the amount of eggs on the flowers is the largest,and the lowest on the leaves.The amount of eggs on tender caudex and bean-pod was between them.The amount of eggs on the middle of cowpea is larger than the else position.4.Five methods of aggregated indices and Iwao's way(regressive relation by m^*-m)and power law of Taylor were used to test the spatial distribution pattern of Maruca testulalis Geyer and Spodoptera litura(Fabricius) in the cowpea field.The results showed that the larvae of Maruca testulalis Geyer was the pattern of symmetrical distribution,and the spatial distribution pattern of the Spodoptera litura (Fabricius) was aggregative.5.According to the choice of 2.5%deliamethrin EC(Decis),15%indoxacarb SC (Avatar),1.8%abamectin EC,4.2%emamectin benzoate EW(Fengchi),5%fipronil SC(Regent),1.7%lambda-cyhalothrin SL(Lvheng),we discovered that the effect of prevention of 4.2%emamectin benzoate EW was better than the others.