title: A floatable formulation and laboratory bioassay of Pandora delphacis (Entomophthoromycota: Entomophthorales) for the control of rice pest Nilaparvata lugens Stål (Hemiptera: Delphacidae).
abstract: BACKGROUND
  The brown planthopper (BPH), Nilaparvata lugens (Staparvata luera: Delphacidae), is a serious rice pest that easily develops resistance to chemical insecticides and resistant rice varieties. This study evaluated the infectivity of the BPH fungal pathogen, Pandora delphacis, and developed a novel formulation as an alternative means of BPH control.
  
  
  RESULTS
  In a multiconidial concentration bioassay, P. delphacis-infected BPH cadavers were observed on day 4, but most occurred between days 5 and 8. BPH mortality depended on the inoculated conidial concentration. The cumulative mortality of adult BPHs reached 81.7% at 192 conidia mm(-2) in 8 days. Inoculation with 40.9 conidia mm(-2) was sufficient to induce 50% BPH death, based on analysis of a time-concentration-mortality model. A floatable P. delphacis-based formulation was made for use in paddy fields; mycelium-containing pellets mimicking mycosed cadavers could produce 7-15.7 × 10(4) infectious conidia pellet(-1) at 11-28 °C. In the laboratory bioassay, three floating pellets in a BPH-rearing jar caused 75.5% BPH mortality within 8 days, similar to the mortality level caused by direct conidial inoculation.
  
  
  CONCLUSIONS
  P. delphacis is a potential biocontrol agent of BPHs for further research, and the novel floatable formulation holds promise as a method for BPH control.
authors: National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang Agricultural and Forestry University, Lin'an, China.
authors: Xiang
authors: X
authors: Zhou
authors: National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang Agricultural and Forestry University, Lin'an, China.
authors: Xiu
authors: X
authors: Su
authors: National Joint Local Engineering Laboratory of Biopesticide High-Efficient Preparation, School of Forestry and Biotechnology, Zhejiang Agricultural and Forestry University, Lin'an, China.
authors: Hongbo
authors: H
authors: Liu
mesh_terms: D000464:Alginates / Q000737:chemistry; D000818:Animals; D020091:Entomophthorales / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006430:Hemiptera / Q000382:microbiology*; D006603:Hexuronic Acids / Q000737:chemistry; D012275:Oryza; D010572:Pest Control, Biological / Q000379:methods*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid
keywords: alginate formulation; bioassay; brown planthopper; sporulation capacity