MỘT SỐ ĐẶC ĐIỂM SINH HỌC LOÀI VE SẦU PHẤN TRẮNG Dundubia nagarasagna Distant (Homoptera: Cicadidae) HẠI CÀ PHÊ VÀ DIỄN BIẾN MẬT ĐỘ VE SẦU TẠI TÂY NGUYÊN
MỘT SỐ ĐẶC ĐIỂM SINH HỌC LOÀI VE SẦU PHẤN TRẮNG Dundubia nagarasagna Distant (Homoptera: Cicadidae) HẠI CÀ PHÊ VÀ DIỄN BIẾN MẬT ĐỘ VE SẦU TẠI TÂY NGUYÊN
Some biological characteristics of cicada species (Dundubia nagarasagna Distant) damaging coffee and density dynamic of cicada in Central Highland
The cicada nymph deeply live in the soil, pierce into root of coffee trees and suck up sap through their needle - like rostrum. Coffee trees become yellow, stunted, if high density of nymph occured causing defoliation and falling fruit. The cicada species D. nagarasagna were reared by the two year old trees of coffee at the condition of temperature 23.4oC; humidity 83 % and temperature 23.8oC; humidity 84%. The nymph duration and the life cycle was 287.5 days; 333.5 days and 275.9 days; 330.6 days, respectively. The number of eggs laid per female was 382.29 and 402.29 at above temperature, respectively, the rate of hatching were 86.3 and 94 % at the temperature previously given. The peak of total nymph density of cicada was about from the end April to the mid May both in Daklak, Lamdong and Gialai, after that decreasing from the end May, but it increase again in September.