广州地区自然条件下扶桑绵粉蚧入侵定殖能力研究

【背景】扶桑绵粉蚧是一种对棉花等作物具有严重威胁的新的外来人侵害虫，2008年8月在广州市区扶桑上发现该虫。关于该虫入侵种群的大小是需要明确的基本人侵生物学问题之一。【方法】采用了野外接虫、定点系统跟踪观察的方法，研究了广州地区番茄、棉花田间扶桑绵粉蚧的最小入侵种群规模。【结果】扶桑绵粉蚧初始种群侵入棉花、番茄田3d后数量急剧下降，分别减少了82．7％、61．2％，进入3龄后田间种群数量呈现持续小幅度减少的规律，进入产卵期的雌虫出现概率分别为2．83％、2．5％。棉花上扶桑绵粉蚧单雌产卵量为532．6粒，明显高于番茄（418．4粒）。棉花、番茄田的入侵种群趋势指数分别为15．09、10．46，下一代种群呈明显增长趋势，能够成功定殖。棉花、番茄田扶桑绵粉蚧自然种群存活曲线均符合Ⅰ型（凹型），存活率（S）与接虫后天数（D）的关系模型分别为S=（1．0000＋1．1．505D）-1.1250,S=（Q9996＋Q124810）^-3.0614。根据进入产卵期雌虫的概率，计算出保证扶桑绵粉蚧成功入侵的最小自然种群规模为36—40头。【结论与意义】广州地区6～8月番茄、棉花田新人侵的扶桑绵粉蚧自然种群存活曲线为Ⅰ型（凹型），最小入侵种群规模为36—40头。该结果为深入研究扶桑绵粉蚧的入侵生物学特性和制定防治策略等提供了依据。

Potential of invasion and colonization for the cotton mealybug Phenacoccus solenopsis Tinsley populations in cotton and tomato fields in Guangzhou, China

Background ] The cotton mealybug Phenacoccus solenopsis Tinsley is a new cotton pest world-wide. The mealybug was found in August 2008 in Guangzhou, and could seriously threaten the cotton production in China. Method ] The invasion and, colo- nization for the mealybug populations in cotton and tomato fields in Guangzhou was investigated by methods of releasing the 1 st instar nymph and following in a systematic survey. Result] The results revealed that the initial population declined sharply within 3 days after release, with a mortality of 82.7% and 61.2% in cotton and tomato fields, respectively. After developed into 3rd nymph, the population decline became slow. The probabilities which females reached oviposition were 2.83% and 2.5% in cotton and tomato fields, respectively. The fecundities of the adult females in cotton and tomato fields were 532.6 individuals and 418.4 individuals/ female, respectively, and population trend indices were 15.1 and 10.5 on the two host crops. The survival curves for the mealybug populations in cotton and tomato fields were fitted to type I, and the relationship between survival rate and the duration could be de- scribed with the models S = （ 1.0000 ＋ 1.1505D） -1.1250 on cotton, and S = （0.9996 ＋0.12481D） -3.0614 on tomato. The minimum in- vasive population producing at least one ovipositing female for P. solenopsis mealybug ranged from 36 to 40 individuals according to the probabilities from 1 st nymph to adult female in oviposition period. Conclusion and significance ] The survival curve of P. solenopsis invading tomato and cotton in June ~ August in Guangzhou was I type （concave）, the minimum level for invasive population is 36 ~ 40 individuals.