这是涉及到一项出口价值每年700万至1千万美元的大事。经过昆虫学家们的研究,市场交易之门重新开放了。从三十年代以来,在华盛顿州很少关于黑森瘿蚊的报导,因而农学家们怀疑这种害虫是否在这个州也存在。到1932年,黑森瘿蚊仅在喀斯开德山脉(Cascade Mountains)以西发现,这并不是大量装运梯牧草到日本去的主要地区。 This is a major event involving an export value of 7 million to 10 million U.S. dollars each year. After the study of entomologists, the door to market trading has reopened. Since the 1930s, very few reports of mosquitoes in the state of Washington have been made in Washington, and agronomists wonder if the pests are also present in this state. By 1932, Hystrix, found only to the west of the Cascade Mountains, was not the main area where large numbers of tails were shipped to Japan.