In places where the Asian citrus psyllid Diaphorina citri is vector of citrus huanglongbing disease, the economic threshold level is almost nule

 D. citri densities varied from 8 for eggs to 4 for adults; projections indicated that a

sampling plan consisting of 10 trees and 8 flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions.

Dear Pradeep Kumar Dalal

Pls. find the attached files

https://www.researchgate.net/publication/251179443_Bio-Intensive_Integrated_Pest_Management_in_Fruit_Crop_Ecosystem

http://cropwatch.unl.edu/economic-injury-level-and-economic-threshold-ipm

http://link.springer.com/chapter/10.1007/978-1-4020-8992-3_21#page-1

http://ipmworld.umn.edu/pedigo

http://pdf.usaid.gov/pdf_docs/Pnadk252.pdf

Hoping this will be helpful

Regards

Prof. Houda Kawas

Article Bio-Intensive Integrated Pest Management in Fruit Crop Ecosystem