Showler Allan T
USDA-ARS IFNRRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596, USA.
J Econ Entomol. 2008 Feb;101(1):68-73. doi: 10.1603/0022-0493(2008)101[68:roacft]2.0.co;2.
Abscised cotton, Gossypium hirsutum L., fruit in field plots planted at different times were examined to assess adult boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), use of squares and bolls during 2002 and 2003 in the Lower Rio Grande Valley of Texas. Although boll abscission is not necessarily related to infestation, generally more bolls abscised than squares and abundances of fallen bolls were not related to the planting date treatments. During 2003, fallen squares were most abundant in the late-planted treatment. Although large squares (5.5-8-mm-diameter) on the plant are preferred for boll weevil oviposition, diameter of abscised squares is not a reliable measurement because of shrinkage resulting from desiccation and larval feeding. Fallen feeding-punctured squares and bolls were most abundant in late plantings but differences between fallen feeding-punctured squares versus fallen feeding-punctured bolls were found in only one treatment in 2003. During the same year, fallen oviposition-punctured squares were more numerous in the late-planted treatment than in the earlier treatments. Treatment effects were not found on numbers of oviposition-punctured bolls, but fallen oviposition-punctured squares were more common than bolls in the late-planted treatment compared with earlier treatments each year. Dead weevil eggs, larvae, and pupae inside fallen fruit were few and planting date treatment effects were not detected. Living third instars and pupae were more abundant in fallen squares of the late-planted treatment than in the earlier treatments and bolls of all three treatments. This study shows that fallen squares in late-planted cotton contribute more to adult boll weevil populations than bolls, or squares of earlier plantings.
对不同时间种植于田间小区的陆地棉（Gossypium hirsutum L.）脱落棉铃进行检查，以评估2002年和2003年德克萨斯州下里奥格兰德河谷地区棉铃象甲（Anthonomus grandis grandis Boheman，鞘翅目：象甲科）对棉蕾和棉铃的利用情况。虽然棉铃脱落不一定与虫害有关，但通常脱落的棉铃比棉蕾多，且掉落棉铃的数量与种植日期处理无关。2003年，晚播处理中掉落的棉蕾数量最多。虽然棉铃象甲产卵更喜欢植株上直径5.5 - 8毫米的大棉蕾，但由于干燥和幼虫取食导致的收缩，脱落棉蕾的直径不是一个可靠的测量指标。晚播中掉落的有取食穿刺孔的棉蕾和棉铃数量最多，但2003年只有一个处理发现有取食穿刺孔的掉落棉蕾与有取食穿刺孔的掉落棉铃之间存在差异。同年，晚播处理中掉落的有产卵穿刺孔的棉蕾比早播处理中的更多。在有产卵穿刺孔的棉铃数量上未发现处理效应，但与每年的早播处理相比，晚播处理中掉落的有产卵穿刺孔的棉蕾比棉铃更常见。掉落果实内死亡的象甲卵、幼虫和蛹数量很少，未检测到种植日期处理效应。在晚播处理掉落的棉蕾中，存活的三龄幼虫和蛹比早播处理以及所有三个处理的棉铃中的更为丰富。本研究表明，晚播棉花中掉落的棉蕾对成年棉铃象甲种群的贡献比棉铃或早播棉花中的棉蕾更大。
