Effects Nutrition Of Tobacco On The Development, Survival And Host Selectivity And Mechanism Of The Q-biotype Bemisia Tabaci

Bemisia tabaci (Gennadias) is an important worldwide distribution insect pest. In recent years it did a lot of harm to tobacco, flowers and vegetables and other economic crops in our country. Because of its short life history, high fecundity and easy acquisition of pesticide-resistance ability, an environmentally friendly control technology is imminent. With tobacco as host plants, this paper adopts a hydroponic experiment method to study the effect of mineral nutrition on Q-biotype Bemisia tabaci development, survival rate and host selectivity, the mechanism of effect on selectivity was preliminary discussed in order to provide theoretical foundation for the control of Q-biotype Bemisia tabaci by regulating the nutrition of host plant. Our main results and conclusions were as follows.1、Nutrient elements screening of the selectivity and adaptability of Q-biotype Bemisia tabaci on tobacco Q-biotype B. tabaci:The selectivity and adaptability of Q-biotype Bemisia tabaci on tobacco were tested by using the tobacco treated with different deficiency nutrient solution and tobacco treated by all nature. The adult number, spawning number and survival rate were choose as evaluate index. The results showed that there were four kinds of nutrition can have a significant effect on the selectivity and adaptability of Q-biotype Bemisia tabaci on tobacco, which were nitrogen, phosphorus, potassium and manganese.2、The selectivity and adaptability of Q-biotype Bemisia tabaci on tobacco treated with single nutrient:The host selectivity, development and survival rate of Q-biotype B. tabaci were investigated on water-cultured tobacco plants with five different concentrations of nitrogen, phosphorus, potassium and manganese. It was shown that developmental duration were prolonged and survival rate were dropped treated with higher concentrations of four kinds of nutrition. The host selectivity of Q-biotype B. tabaci were poor on tobacco plants treated with medium concentration of nitrogen or manganese and high concentration of phosphorus or potassium Therefor Q-biotype B. tabaci populations can be managed by regulating the potassium nutrition of tobacco plants.3、The relationship between Q-biotype B. tabaci survival rate and nitrogen, phosphorus, potassium and manganese nutrition composition:Nitrogen, phosphorus, potassium and manganese, four kinds of the change of the nutrient concentration (nitrogen nutrition:7.5-22.5 mmol/L, phosphorus nutrition:15～20 mmol/L, potassium nutrition:6～12 mmol/L, manganese nutrition:0.005～0.02 mmol/L) were designed according to the results of single factor experiment. The influence of different fertilization combinations to B. tabaci mortality were conducted by using quadratic general rotary unitized design. It was shown that nitrogen, phosphorus, potassium, manganese four kinds of nutrition have a significant impact on B. tabaci mortality. The contribution to the mortality were, in order N>K>Mn>P. There was no significant interaction between four kinds of nutrient elements. Opt the solutions statistical, the highest mortality rate can be reached 35.17% within the scope of the test.4、The mechanism for selectivity of Q-biotype B. tabaci on tobacco with different concentrations of nutrition:Investigated the trichome density, the color of leaves and the behavior reaction to tobacco treated with different concentrations of nitrogen, phosphorus, potassium and manganese. We found that the trichome density was significantly different on tobacco treated with different concentrations of nitrogen, phosphorus, potassium and manganese. The trichome density, except treated with nitrogen nutrition, have significantly correlated with adult host preference and the number of eggs laid. Nutrition can change the external morphological characteristics of tobacco, in turn, affect the host selectivity of B. tabaci.