Climate change matters: cotton bollworm rampant with less late spring cold occurrences

Climate change may favour destructive agricultural pest and bring harm to crops in temperature regions, a recent study by scientists from Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences showed. 

 
Helicoverpa armigera, commonly known as cotton bollworm, is a major pest in cotton. The species is widespread in central and southern Europe, temperate Asia, Africa, Australia, and Oceania.

  
Scientists analyzed the empirical data of Helicoverpa armigera moth populations from three sites over 12 to 13 years in northwestern China, and uncovered how changes in spring temperatures impact crop pest population dynamics in temperate regions. 

 
Late spring cold (LSC) events decrease in the last decade. Using model simulations, XIEG researcher Lv Zhaozhi and his group explored the relationships between LSC parameters and moth population dynamics. 

 
"The abundance of H. armigera will increase as the frequency and duration of late spring cold events decrease under global spring warming," said Lv.

  
Their model showed that the timing of the LSC event had a major effect on influence on each H. armigera generation. The eclosion timing of the overwintering generation was critical, and determined the abundance of the first and subsequent generations, according to the study.

  
Duration and timing of LSC events should be taken into account in forecasting of H. armigera and other devastating insect pest under global warming, the study suggests.

 
Results of the study were published on Journal of Pest Science as “Climate change favours a destructive agricultural pest in temperate regions: late spring cold matters”.