[Control effect of blue light on Bemisia tabaci]. / è“å ‰å¯¹è”¬èœçƒŸç²‰è™±çš„æŽ§åˆ¶ä½œç”¨.

Light is a important way in controlling vegetable pests. In this work, we examined the effects of blue light on Bemisia tabaci on cucumbers, as well as on nutrients, secondary metabolites, and resistance-related enzymes in cucumbers. Results of the direct repellent test showed that blue light had a strong repellent effect on B. tabaci, which increased with light intensity and exposure time. The repellent effect of direct light was stronger than that of transmitted light under the same light intensity and time. The population decline rate of B. tabaci was 77.7% after direct exposure to 1200 lx blue light for 5 min, being 17.4% higher than that of transmitted light. After 2 min exposure to 1750 lx blue light, the population decline rate was 41.2%, which was 10.6% higher than that of transmitted light. Under the condition of pot culture, blue light also had a good repellent effect on B. tabaci on leaves. The corrected population decline rate of B. tabaci reached 88.5% after 5 h exposure to 100 lx blue light. Blue light affected the development of B. tabaci. In addition, blue light significantly increased the contents of soluble sugar, free protein, total phenols and flavonoids in cucumber leaves, decreased the content of proline. The contents of trans-ß-farnesene, trans-2-hexenal, cis-4-heptanal, trans-ß-ocilene, D-carvone, longifolene and 3-carene, and the activities of peroxidase, catalase, superoxide dismutase, ascorbate peroxidase were significantly increased. The results suggested that blue light could drive off B. tabaci and influence the resistance of cucumber. 100 lx blue light had a good control effect on B. tabaci.

[Effects of alcohol extracts from three kinds of biomass energy plant tissues on biological activity of Bemisia tabaci].

To test the feasibility of using raw extracts from the tissues of biomass energy plants Ricinus communi and Kosteletzkya virginica as plant protection agents, the alcohol extracts from R. communi seed and leaf and from K. virginica leaf were used to treat adult Bemisia tabaci by spraying. The glutathione S-transferase and carboxylesterase activities in B. tabaci body were measured after treated for 4 h, 24 h, 48 h, 72 h, and 96 h, and the olfaction responses of B. tabaci to the alcohol extracts were detected with a Y-tube olfactomet. All the three alcohol extracts obviously inhibited the glutathione S-transferase and carboxylesterase activities in a concentration-dependent manner. The inhibitory effect of the 250-times diluted alcohol extracts on the two enzyme activities was equivalent to that of 3000 times-diluted 1.8% avermectins. In addition, the 250-times diluted alcohol extracts had obvious repellent effect on B. tabaci, with the repellent coefficient of the alcohol extracts from R. communi seed and leaf and from K, virginica leaf being 100.0%, 96.7%, and 79.4%, respectively. All of these suggested that the test three alcohol extracts had repellent and other biological effects on B. tabaci.

[Flight behaviors of Bemisia tabaci and corresponding IPM strategies].

Bemisia tabaci, a pest insect with stronger capabilities of flying and host plant-exploitation, is capable of flying 150 m high and over a distance as far as 7 km, but hardly flies higher than 0. 5 m and long distance in food-abundant areas. B. tabaci has the characteristics of both searching-and migrating flying, which enable it to exploit and locate on suitable hosts. Up to now, no oogenesis-flight syndrome of B. tabaci has been detected. Visual spectrum, air temperature and relative humidity, host quality, and wind speed are the main factors affecting the flight behavior of B. tabaci. In this paper, the flying capability of B. tabaci and the factors affecting its flight behavior were summarized, and the corresponding IPM strategies in the areas where B. tabaci could not overwintering in open field were discussed.