Effects of host plants on the growth,development and fecundity of Bradysia difformis
Gou Yuping;Liu Qian;Liu Changzhong;Pratacultural College of Gansu Agricultural University,Key Laboratory of Grassland Ecosystem of Ministry of Education,Gansu Provincial Laboratory of Grassland Engineering;
The chive gnat,Bradysia difformis Frey,damages the underground parts,and causes heavy losses to Chinese chive,spring onion,lily,garlic and other crops.Studies on the growth,development and reproductive rhythm of B.difformis on different host plants can provide scientific evidences for prediction and prevention of this pest insect.The experiments were conducted in artificial climate chamber at the temperature of(25±1)℃,dim light(251.2lx)and RH 80%±5%,using Chinese chive,spring onion,lily and garlic(garlic bulbs and garlic stems of different developmental periods)as the test plants.Life tables were established and the population dynamics parameters such as the intrinsic rate of increase(rm),net reproductive rate(R0),mean generation time(T),the population doubling time(t)and the finite rate of increase(λ)were calculated.The results indicated that the shortest developmental duration of eggs was on Chinese chives(3.49d)and the longest on garlic bulbs(4.91d).When B.difformis were fed on Chinese chives and spring onions,the larval duration was the shortest,but when fed on lilies,the longest.The shortest pupal duration was on Chinese chives(2.95d),while the longest on lilies(4.05d).The effects of host plants on egg hatching rate and pupal survival rate of B.difformis were not significant,but host plants significantly affected the larval survival rate.The highest larval survival rate was on Chinese chives(76.7%),and the lowest on garlic bulbs(30%).The average egg number per female on Chinese chives,spring onions,liliesand garlic bulbs and stems were 91.98,52.14,85.48,73.91 and 72.96,respectively.The net population growth rate(R0),the intrinsic rate of increase(rm)and finite rate of increase(λ)were the highest on Chinese chives,and the mean generation time(T)and population doubling time(t)were the shortest on Chinese chives.B.difformis had the best adaptability to and fastest breeding rate on Chinese chives.
【CateGory Index】： S433
【CateGory Index】： S433