| Beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae), also named Laphygma exigua Hübner, is one of important pests in the world. It has characteristics of wide distribute range, many host plants, strong ability of migration and dispersal, liking warm and ability of abiding high temperature. The endanger area distributes in Asia, North America, Europe, Australia andAfrica. Beet armyworm disserve vegetable, Beet armyworm is a kind of polyphagous pest, and they can eat 35 families 108 genera, 138 species of plants, including 28 kinds of field crops, 32 kinds of vegetables. Before the eighties of the 20th century, the beet armyworm was only a kind of sporadic pest in our country, but since 1986, beet armyworm has expanded in our country gradually, now, spread provinces and cities in our country more than 20, and have the tendency to expand constantly, cause high disaster frequency, endanger becoming more serious. Based on the insect nutrition ecology theory and in view of the beet armyworm bioecology characteristic, the systemic research of the influence of beet armyworm development, the population dynamics and AChE and CarE activity on protein, sugar and so on the main nutrients and different host plants, the larvae of beet armyworm feeding taxis to the different host plants were conducted. The results were summarized as follows.1 The influence of different protein content and dextrose content on increase of beet armyworm populationBased on laboratory artificial diets, Penman changed the protein content and dextrose content in beet armyworm larva artificial diets by menthod of changing the component and dosage of artificial diets, and observed the influence of different treatments on larval development and adult fecundity. The results showed that the increase of the protein and dextrose content can promote the population of the beet armyworm to increase effectively. With the increase of the protein and dextrose content, larval survival rate increased, larval duration shortened, adult and pupa durations increased, pupa weight and average No. of egg laid by per female adult increased.2 The influence of different host plants on increase of beet armyworm development and fecundityPenman choiced three beet armyworm host plants (asparagus lettuce, water spinach, pakchoi) in Chongqing region as the larvae diets of beet armyworm, and observed the influence of different host plants on increase of beet armyworm development and fecundity. The results showed that the influence of larval period, survival rate, pupae period, pupae weight and adult duration, adult fecundity of beet armyworm have varied degrees of differences with larvae feeding different host plants. Three beet armyworm host plants,with feeding asparagus lettuce, the beet armyworm larvae has the shortest larval period(13.0d±0.56), the highest survival rate(44.8%), the longest adult duration (4.0±0.85d) and the largest pupae weight (94.1±50.45mg) ;With feeding water spinach, the larval period (14.3±0.49d) , the survival rate (33.3%) , the pupae duration(6.1±0.64d),the adult duration(3.9±0.69d) and the pupae weight(56.5±10.32mg);With feeding pakchoi, the larval period (15.7±1.23d) , the survival rate (42.0%) , the pupae duration(4.5±0.60d),the adult duration (3.9±0.69d) and the pupae weight (63.6±6.56mg) .3 The influence of different protein content and dextrose content on beet armyworm energy substancesPenman changed the protein content in beet armyworm larva artificial diets by menthod of changing the component of artificial diets.The results showed that : 1 In a laboratory experiment, 2nd-4th instar larval soluble protein of beet armyworm,increased with protein in the artificial diets within the range of the protein concentrations used, and 5th instar larval soluble protein with protein in the artificial diets to a certain point, followed by a decline.In 24% of the protein concentrations used(treatment4), larval has the largest soluble protein(3.1278mg/ larval).2 2nd instar larval soluble protein of beet armyworm has no significantly difference,3rd-4th instar larval glycogen of beet armyworm increased with protein in the artificial diets within the range of the protein concentrations used, to a certain point, followed by a decline.3 2nd-5th instar larval triglyceride of beet armyworm,increased with protein in the artificial diets within the range of the protein concentrations used, to a certain point, followed by a decline.In 20% of the protein concentrations used(treatment4), larval has the largest triglyceride (0.1889mg/larval,0.8436mg/larval,2.1759mg/ larval,3.5320mg/ larval).4 pupa, adults glycogen, soluble protein of beet armyworm,increased with protein in the artificial diets within the range of the protein concentrations used to a certain point, followed by a decline. In 20% of the protein concentrations used(treatment3), larval has the largest triglyceride (1.7830mg/larval,1.8042mg/larval).The results showed the same with beet armyworm raised with changed the soluble sugar content in beet armyworm larva artificial diets.4 The influence of different host plants on beet armyworm energy substances and host plantsPenman choiced three beet armyworm host plants (asparagus lettuce, water spinach, pakchoi) in Chongqing region as the larvae diets of beet armyworm. The results showed that the influence of larval energy substances increased with the development with beet armyworm larvae feeding different host plants.With feeding three beet armyworm host plants, larval soluble protein of beet armyworm, Spodoptera exigua (Hübner) with asparagus lettuce feeding is higher than larval soluble protein of beet armyworm with asparagus lettuce feeding water spinach, larval soluble protein of beet armyworm with water spinach lettuce feeding is higher than larval soluble protein of beet armyworm with asparagus lettuce feeding pakchoi; the influence of larval glycogen of beet armyworm is asparagus lettuce＞water spinach＞pakchoi; the influence of larval triglyceride of beet armyworm is pakchoi＞water spinach＞asparagus lettuce.At the same time penman determined the nutrition substances of three beet armyworm host plants (asparagus lettuce, water spinach, pakchoi), especially the crude protein and soluble sugar content,then analyzed the the relationship between the nutrition substances of three beet armyworm host plants and armyworm development, armyworm energy substances. The results showed that, among several kind of host plants, the crude protein content in water spinach (2.223g/100g) is asparagus lettuce feeding pakchoi; the influence of larval glycogen of beet armyworm is asparagus lettuce＞water spinach＞pakchoi; the influence of larval triglyceride of beet armyworm is pakchoi＞water spinach＞asparagus lettuce.At the same time penman determined the nutrition substances of three beet armyworm host plants (asparagus lettuce, water spinach, pakchoi), especially the crude protein and soluble sugar content,then analyzed the the relationship between the nutrition substances of three beet armyworm host plants and armyworm development, armyworm energy substances. The results showed that, among several kind of host plants, the crude protein content in water spinach (2.223g/100g) is highest, next is pakchoi (1.556g/100g) , asparagus lettuce (1.421g/100g) is the lowest;but the soluble sugar content in asparagus lettuce (3.662g/100g) is highest, next is pakchoi (3.652 g/100g), pakchoi (1.159g/100g) is the lowest. The correlated analysis results showed, the development and fecundity with eating different host plants with crude protein content negative correlation; the last larval energy substances with crude protein content positive,with soluble sugar content negative correlation; the development and fecundity of beet armyworm with the ratio of soluble sugar content to crude protein content positive correlation, the last larval energy substances with the ratio of soluble sugar content to crude protein content negative correlation.As important content and energy: protein and soluble sugar,as well as their ratio in food plan would promote the population of the beet armyworm in proper field.
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