Ecological studies on Spodoptera exigua (Hubner) and its biological control by the novel parasitoid, Cotesia ruficrus (Haliday) (Hymenoptera: Braconida) on sugar beet
Keywords:Cotesia ruficrus, protecto, Spodoptera exigua, sugar beet, productivity
Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae) is one of the polyphagous insects destroying crops which included sugar beet global. It causes a highly reduction in sugar percentage and roots weight. parasitoids are the most element used around the world in biocontrol of insects. The current inquiry was conducted during the two succeeding growing seasons of 2019/2020 and 2020/2021 at the Experimental Farm of the Sakha Agricultural Research Station. The results obtained showed that seasonal parasitism percentage of Cotesia ruficrus on S. exigua larvae were 24.23, 22.86 and 34.33% during the first season 2019/2020. While was 21.48, 20.39 and 27.58%
in the second season 2020/2021 throughout the three cultivations, respectively. This is the first report about parasitoid on S. exigua and their occurrence in Egyptian sugar beet fields, highly significant correlation was recorded between S. exigua larvae and parasitoid in three cultivations respectively. Biocide (Protecto) reduced S. exigua numbers with 51.51 and 52.26%, and C. ruficrus with 18.60 and 22.67%. While, conventional insecticide (Chlorpyrifos), reduce S. exigua with (88.50 and 92.11% and C. ruficrus with 99.06 and 100%) in the two seasons, respectively. Insignificant differences between sprayed plots with Protecto and Chlorpyrifos in both root and sugar yield of sugar beet were observed. In addition, C. ruficrus and protecto are consider as vital elements in the integrated pest management (IPM) Program against S. exigua. The sensible and justifiable application of biological control is the primary factor in the control of the insect pest complex throughout the sugar beet crop.
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