The Boll Weevil
The Boll Weevil
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棉铃象甲虫
DOI：
10.4135/9781483300528.n23
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发表时间：
2010
影响因子：
3.4
通讯作者：
Walter M. Riggs
中科院分区：
文献类型：
--
作者：
Nathaniel Barksdale Dial;Richard I. [from old catalog] Manning;Walter M. Riggs
棉铃象鼻虫，无疑是墨西哥或中美洲的土著，大约四分之一英寸长，三分之一宽。发育中的幼虫在蕾（花蕾）或铃（果实）中获得的食物量导致象鼻虫大小的差异。颜色从浅黄色到灰色或接近黑色，取决于它的年龄。棉铃象鼻虫是由瑞典昆虫学家Boheman从他从墨西哥获得的标本中首次发现的。我们对它在墨西哥的传播知之甚少。它穿过德克萨斯州布朗斯维尔附近的格兰德河，在1892年左右。到了1894年，它已经传播到德克萨斯州南部的六个县。它每年前进40到160英里，到1922年，它已经在我们的棉花带上出没了85%以上。在棉花带的虫害地区生产棉花是可能的，因为大约95%的冬眠成虫死亡，许多真正活过冬天的成虫在棉花产生可以产卵的方格之前出现并死亡。即使在产卵和象鼻虫开始发育之后，高温、干燥的天气、昆虫寄生虫和捕食者以及鸟类也会在物质上帮助阻止象鼻虫的快速繁殖。如果没有这样的自然干扰，一对棉铃象鼻虫的后代在一个季节中可能达到数百万。利用寄生虫防治棉铃象甲的可能性已引起人们的极大关注。在不同的州饲养的所有寄生虫中，约有80%是茧蜂。其他重要的物种是Triaspis curculioniSy Eurytoma carderidae，Catolaccus hunterij Zatropis incertus，Eupelmus cyaniceps amicuSj和Myiophasia globosa。棉铃象幼虫被寄生率约为6%。偶尔寄生率会高达30%。在一些地方，整个季节都高达20%。来自肯尼亚殖民地的Bracon kirkpatricki）和来自秘鲁的Triaspis vesticida和Bracon vesticida已被释放到棉田，但我们没有证据表明其中任何一种已在美国定居。棉铃象甲造成的危害每年变化很大。例如，在1950年，棉铃象鼻虫的危害比1921年和1922年以来的任何一年都大，在整个棉花带，阿肯色州、北卡罗来纳州和弗吉尼亚州是有记录以来最大的。夏末秋初的气候条件影响着棉铃虫取食和繁殖材料的供应，决定了棉铃虫越冬的数量和条件。冬季的低温严重影响了次年春夏的生存和出苗。在整个棉花生产期间，降雨和温度的影响最为重要。这些因素中的每一个都构成了一项单独的研究。在路易斯安那州的塔卢拉，从6月21日到8月19日，在控制棉铃象甲的试验区，降雨量在0.3英寸或以上的天数与产量增加的百分比之间的相关性比任何其他两个变量之间的相关性都大。
The boll weevil, undoubtedly a native of Mexico or Central America, is about one-fourth inch long and a third as wide. The amount of food the developing larva gets in the square (flower bud) or boll (fruit) causes differences in the size of the weevils. The color varies from light yellow to gray or nearly black, depending on its age. The boll weevil was identified first by the Swedish entomologist Boheman from specimens he got from Mexico. We know little about its spread through Mexico. It crossed the Rio Grande River near Brownsville, Tex., in 1892 or so. By 1894 i^ ^^^ spread to six counties in southern Texas. It advanced 40 to 160 miles a year and by 1922 it had infested more than 85 percent of our Cotton Belt. It is possible to produce cotton in the infested part of the Cotton Belt because about 95 percent of the hibernating adults die and many that actually survive the winter emerge and die before cotton produces squares in which eggs may be deposited. Even after egg deposition and weevil development have started, heat, dry weather, insect parasites and predators, and birds help materially to check the rapid multiplication. Without such natural interference, offspring of a single pair of boll weevils could amount to several millions in one season. Much attention has been given to the possible control of the boll weevil with parasites. About 80 percent of all the parasites reared in the different States have been Bracon mellitor. Other species of importance are Triaspis curculioniSy Eurytoma tylodermatis, Catolaccus hunterij Zatropis incertus, Eupelmus cyaniceps amicuSj and Myiophasia globosa. About 6 percent of the boll weevil larvae were parasitized. Occasionally parasitization has run as high as 30 percent. In a few localities it has remained as high as 20 percent throughout the season. Bracon kirkpatricki) from Kenya Colony, and Triaspis vesticida and Bracon vesticida, from Peru, have been released in cotton fields, but we have no evidence that any of them have become established in the United States. The damage caused by the boll weevil varies greatly from year to year. During 1950, for example, boll weevil damage was greater than for any year since 1921 and 1922 over the Cotton Belt as a whole and was the greatest ever recorded in Arkansas, North Carolina, and Virginia. The supply of feeding and breeding material, which is affected by weather conditions during the late summer and early fall, determines the number and condition of boll weevils for hibernation. Low temperatures in winter greatly influence the survival and emergence during the following spring and summer. The effect of rainfall and temperatures is most important throughout the period of cotton production. Each of these factors constitutes a separate study. At Tallulah, La., a greater correlation occurred between the number of days on which there was 0.3 inch or more of rainfall from June 21 to August 19 and the percentage of increase in yield in experimental plots where boll weevils .were controlled than between any other two variables.