海南甘蔗蝗虫的暴发及其防治对策

根据甘蔗蝗虫发生的基本规律以及成虫、若虫大量取食蔗叶的特点,针对今年海南甘蔗蝗虫的发生呈上升、蔓延、暴发的态势,从生态学的角度,分析了甘蔗蝗虫暴发的原因,阐述了生态控制是防蝗治蝗的根本对策,强调甘蔗蝗虫的防治必须遵循综合治理的原则,要求应用农业的、人工的、化学和生物的防治技术,压低虫源基数,降低暴发频率。同时提出了在确保人、畜、水产和环境安全的条件下,及时采取的一些应急化学防治技术措施。     

Cuticular hydrocarbons of gregarious and solitary locustsLocusta migratoria cinerascens

The cuticular hydrocarbons ofLocusta migratoria cinerascens—larvae and adults, males and females, gregarious and solitaries—have been investigated by combined gas chromatography-mass spectrometry. The hydrocarbons comprise 52–78% of the cuticular lipids and are divided inton-alkanes (28.7–47.3%), 3-, 4-, and 5-methylalkanes (11.3–15.8%), internally branched monomethylalkanes (13.7–19.9%), and internally branched dimethylalkanes (19.8–35.9%) with seven or nine methylenes between the two branch points. While the sexual dimorphism does not seem to be reflected in the cuticular hydrocarbon composition, clear quantitative variations favoring the longest chain alkanes have been observed between gregarious and solitary locusts, thus revealing a new phase character in these insects.     

Composition and role of volatile substances in atmosphere surrounding two gregarious locusts,Locusta migratoria andSchistocerca gregaria

Volatile substances in the atmosphere surrounding gregarious locustsSchistocerca gregaria andLocusta migratoria were captured and investigated by combined gas chromatography-mass spectrometry. Three aromatic derivates have been identified: phenol, guaiacol, and veratrole. Their relative percentages differ for different ages and species. Behavioral tests show that essentially phenol, guaiacol, and the mixture of the three products tend to increase the aggregation behavior in both species and thus act as cohesion pheromones.