| Bemisia tabaci is the main injurious insect of greenhouse vegetable, and this kind of insect can be found in most regions of our country, resulting in great loss in agricultural production. Because the biological characteristics of B. tabaci and lack of efficient preventing measures in production, the main prevention of B. tabaci is still mainly chemical prevention. The traditional chemical prevention will easily result in environment pollution and may make B. tabaci become resistant to drugs. This kind of prevention may also result in vegetable pesticide residue. So this kind of method can not satisfy the needs of modern vegetable industry. Therefore, building efficient comprehensive prevention system has become present research hotspot. On the basis of the occurrence and harm study of B. tabaci, this paper has studied the preventing effect of castor-oil plant avoidance, celery intercropping, jasmonic acid methyl ester inducing insect resistance of plant. Select several kinds of pesticide that have good prevention effect on B. tabaci and set up a set of ecological regulation system of greenhouse vegetable B. tabaci prevention, which provided scientific evidence for the prevention of B. tabaci.1、The study results of population status of B. tabaci on different greenhouse vegetable and under different equipment in Jiangsu indicate that, the occurrence condition of greenhouse vegetable in different region of Jiangsu are different. In the middle area of Jiangsu, the harm caused by B. tabaci started from the last 10-days of April while the north area of Jiangsu started from the first 10-days of May, with the temperature rising, the number of B. tabaci also increased. On the autumn crops, the B. tabaci began to harm the greenhouse vegetables at middle and north area of Jiangsu at first and middle 10-day of October. With the decrease of the temperature, the population in the open field continuously enters into the greenhouse and the B. tabaci on the greenhouse vegetable continuously increase. The B. tabaci population dynamic states in different greenhouses are different. The number of B. tabaci in greenhouse is larger than that in the ordinary house and it also has a long continuity.2、The effects of different population densities of B. tabaci on pepper yield and quality were studied in a solar greenhouse. The results showed that B. tabaci produced significant harmful effects on pepper yield and quality. The bigger the B. tabaci population was,the more severe effects were observed on pepper yield and quality. When the population of nymph on the plant leaves was maintained at 20-30 heads per cm2, there was a reduction of 28.01% and 30.99% in chlorophyll content of leaves and green pepper 8.48% in average fruit weight,15.73% in fruit weight per plant,6.37% and 4.64% in soluble sugar, vitamin C, and protein content. When the population of nymph on the plant leaves reach a level as high as 50-60 heads per cm2, there was a reduction of 39.86% and 53.52% in chlorophyll content of leaves and green pepper fruit, 29.04% in seed setting rate,45.82% in fruit weight per plant,41.08%,32.51%, and 6.99% in soluble sugar, vitamin C, and protein content. Our results indicated that early prevention of B. tabaci should be conducted on pepper plants.3、Sprinkled jasmonic acid methyl ester to induce B. tabaci resistance of tomato, and we found that jasmonic acid methyl ester can evidently change the volatile matter of the tomato plant and the nutrition matter and resistance substance in the sleeve and improve its resistance to B. tabaci. The higher the concentration of jasmonic acid methyl ester is, the stronger the resistance it will be. When the spraying concentration is 10-6 mol/L, the percentage composition of a-pinene and (3-caryophyllene, which has avoidance effect on B. tabaci, have increased by 1.70% and 0.51%, the percentage composition of myrcene, which has attracting effect on B. tabaci, has decreased by 0.58%, the content of contents of soluble sugar, free proline and protein in the sleeve have decreased by 0.38%,6.47% and 3.53% respectively, the content of flavonoids and phenolic compound have increased by 65.93% and 48.46%. The higher the spraying concentration is, the more obvious the volatile matter of the tomato plant, and the nutrition matter and resistance substance is.After the B. tabaci eating the tomato sleeves that have been treated by 10-7 jasmonic acid methyl ester, POD, SOD and CAT enzyme in its body are the same with the contrast and stay in a steady state. After eating the tomatoes that have been treated by 10-4、10-5、10-6 mol/L jasmonic acid methyl ester, the POD and SOD change in its body are the same. Compared with the contrast, they all have been increased. With the extending of the eating time, it presents a rising trend. The CAT activity in its body presents a first-rise late-decrease trend. And the higher the treating concentration of jasmonic acid methyl ester is, the more evident the changing trend is.4、We systematically studied the effects of growing castor-oil plants outside of sunlight greenhouse containing Chilli, planting celery between rows of tomato, adjusting the planting time, and spraying methyl jasmonate on the Chilli. Results show that growing castor-oil plants outside of sunlight greenhouse, planting celery between rows of tomato can effectively control the Chilli, with methyl jasmonate on the tomato can reduce the happening of Chilli. The effect is more obvious with the increase of spraying concentration and number. In the autumn, the planting time of Chilli should be postponed to avoid the peak time at which B. tabaci enters the greenhouse, which would reduce the population density significantly. Compared with an area in which B. tabaci was controlled with imidacloprid, the comprehensive control area (celery, castor and MeJA treatment) showed better performance, with the number of B. tabaci adults and nymphs reduced by 63.4% and 59%, respectively.By selecting and studying on a few chemical agents,5% technical system granules,50% Kelishi water dispersible granule and 0.3% azadirachtin missible oil have good preventive effect on nymph and imago of B. tabaci.Based on the above study, green prevention and control technical system of B. tabaci is set up for protected vegetable. |
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