English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Strains of the rice brown planthopper and small brown planthopper with 360and 370fold resistance to malathion were respectively and successively selected with fenvalerate to trace the changes of LD50 values of malathion and fenvalerate. The LD50 value of malathion markedly decreased during the first five to six generations of selection in both planthoppers, but little changed by further selection (equilibrated state). In both planthoppers, the LD50 value of malathion in the final (19th) generation of selection was about 1/4 that of the parent strains. In the fenvalerate-selected strain of the rice brown planthopper, the LD50 values of fenitrothion, diazinon and phenthoate decreased to 1/2 to 1/5 during the selection of the first seven generations. In the fenvalerate-selected strain of the small brown planthopper, on the other hand, decreases in the LD50 value of these insecticides were minimal. The LD50 value of fenvalerate increased in the fenvalerate-selected strains of the two planthoppers. This increase, however, did not proceed in proportion to the change in the level of resistance to malathion; the LD50 value did not markedly increase before the level of resistance to malathion reached an equilibrium. In the final (19th) generation of selection, the LD50 value of fenvalerate was about 11-times as high as those in the corresponding parent strains in the rice brown planthopper, and about 5-times in the small brown planthopper.

Effects through Successive Selection with Fenvalerate on Malathion-Resistant Strains of the Rice Brown Planthopper and the Small Brown Planthopper