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The Oviposition Behavior And Insecticide Selection Against Eggs In The Legume Pod Borer, Maruca Vitrata (Lepidoptera: Crambidae)

Posted on:2016-12-31Degree:MasterType:Thesis
Country:ChinaCandidate:H Y WangFull Text:PDF
GTID:2283330485478086Subject:Agricultural Entomology and Pest Control
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Maruca vitrata Fabricius(Lepidoptera: Crambidae) is one of the main pests on grain legumes, and can cause great yield loss. Still, as is no environmentally friendly controlling method, insecticides are most widely used in China and even all over the world, which has lead to the resistance against insecticides and excessive insecticide residues. However, most of these problems can be ascribed to the lack of the research on and attention to the biological properties of M. vitrata. Thus, it is of great significance of intensive study on the biological properties of M. vitrata, and on this base, using insecticides more reasonablely may be more appropriate. In this study, we observed the oviposition property and measured the toxicity of different insecticides against the eggs and newly hatched larva of M. vitrata, aiming at providing the appropriate timing, position and insecticide to the chemical control of M. vitrata. Main results are as following:1. The ovary of the 1-2 day-old female is immature, and after the two days of yolk deposition and the ovarioles development, the ovary turns mature and the length of the ovarioles significantly elongated. The accumulated mating rate significantly increased at the 3rd day after paring when emerging, reached 80.31%, and continuously increasing until 5th day, most of the females can be mated. Under various temperature and photoperiod conditions, the peak of oviposition always appeared at the 1st hour into the scotophase; the peak of egg hatching appeared at early to metaphase and latter phase. Laboratory and field bioassays showed that female adults always prefer laying eggs at the flower buds of the host plant, instead of others parts.2. We also evaluated the toxicity of 5 kinds of insecticides against the eggs and the newly hatched larva of M. vitrata. Beta-cypermethrin is the most effective insecticide against the eggs, and the LC50 is 8.391mg/L; Abamectin and chlorantraniliprole shows more effective against newly hatched larva, the LC50 are 0.355 mg/L and 0.401mg/L respectively.Our study showed that the female adult of M. vitrata would be sexually mature in 3 days after eclosion and mated in 5 days. The female would lay eggs in the first hour of the scotophase, and mainly on the flower buds of the host plant, while neonate larvae come out from the eggs during the scotophase under different conditions. Beta-cypermethrin killed most eggs of M. vitrata, and Abamectin and chlorantraniliprole killed most neonate larvae of M. vitrata. So, it may be an effective way to spray beta-cypermethrin, abamectin and chlorantraniliprole or the appropriate mixtures of the three insecticides to control M. vitrata in the egg stage in the field, the spraying time may be selected toward evening.
Keywords/Search Tags:Maruca vitrata, internal-reproductive system, oviposition rhythm, oviposition preference, insecticides
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