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2012年2月12日,星期日

Larvae in fruit: distinguishing between spotted wing drosophila and other internally feeding fruit pests

It finally feels like winter in North Carolina, which may seem like a strange time to talk about pest of ripe fruit. However, this morning I answer what I expect to be the first several questions from a homeowner who had "lots of maggots" (we prefer to use the term larvae here) in their fruit last summer and wanted to be prevent the same issue from occurring this year. In this case, the homeowner was growing blueberries and was searching for tools to monitor and manage blueberry maggot.

Before 2010, it would be reasonable to assume that blueberry maggot (Rhagoletis Mendax) larvae would be the most likely insect to be present in infested ripe blueberries grown in North Carolina. However, the establishment of斑点的果蝇(SWD)在整个美国东部意味着不再安全地假设在蓝莓(或黑莓,覆盆子,草莓和其他柔软的皮肤水果)中发现的蝇幼虫是本地昆虫而不是SWD。重要的是要正确确定在商业或家庭种植的水果中存在哪些害虫,因为害虫物种的管理策略会有所不同。如果您怀疑自己的水果中有这些昆虫,请联系您县合作推广代理or

I posted this summer about insects that might be present in“有趣的”蓝莓并包括有关蓝莓,蔓越莓和樱桃果虫的两个毛毛虫病虫的信息和链接。我不会回顾这些害虫和蝇幼虫之间的区别,除了重申,如果幼虫有腿(即使它们很小),那不是我们的蝇虫之一。

为了确定您的水果中是否存在幼虫,请至少收集30种成熟的良好水果。如果您要种植多种或种类的水果,请从每个水果中收集一个单独的样本。至关重要的是只能采样声音。如果您不吃水果,请不要采样!许多非害虫昆虫会以过度的成熟,损坏或腐烂的水果为食,并采样这种水果可能会导致您得出结论,如果您实际上没有,就会出现问题。您绝不应该根据您不会吃或出售的农作物做出管理决定。

一旦收集样本,您可以通过几种方法来确定水果是否被侵扰。这些包括简单地解剖或粉碎水果并寻找活幼虫。如果您的样品数量相对较少,眼睛(或手镜头),这是最简单的方法。但是,当您有大量样品时,水果清除可能会很耗时,如果您不仔细看,就可能会错过幼虫。俄勒冈州立大学的SWD研究人员发布了一个视频,详细介绍了水果扣篮方法here。该方法涉及冻结样品,从而导致幼虫退出果实,然后将冷冻的水果从幼虫中飘散,这可以在容器的底部观察到。最后,可以将盐或糖溶液倒在缓慢压碎的水果上,这鼓励幼虫退出。当在黑暗的表面上进行操作时,很容易看到幼虫移动。保护我们,这是一个佛罗里达大学的侵入性物种检测和监测计划,有一个张贴的视频,描述了盐和糖测试here

All of these tests will help you determine if you have larvae in your sample but not what the larvae are. If you find fly larvae in sound, otherwise harvestable blueberries, they are most likely either blueberry maggot or SWD. These two different pests can be distinguished from one and other based on shape and size. Shape is the most reliable differentiator between these two pests. Blueberry maggot larvae are "carrot-shaped". Their head end, with dark mouth parts often visible, is tapered to a point and their rear end, with six, light brown spiracles (breathing holes; in two rows of three) is flattened. Larvae of all果蝇包括SWD在内的spp。在两端都逐渐变细,其呼吸管在其后端达到一定程度。

Larva of "true" fruit flies (Tephritids), which include the blueberry maggot fly, cherry fruit fly, and many others (top); larva of "vinegar flies" (Drosophilids), which include spotted wing drosophila and many native species (bottom).
SWD和蓝莓型幼虫也可以通过大小来区分。一个完整的蓝莓虫幼虫的大约是完整的果蝇幼虫的两倍。但是,中年蓝莓虫的幼虫的大小将与SWD幼虫相似,因此形状是一种更可靠的工具。

Spotted wing drosophila larvae in ripe yellow raspberry, a closer detail in upper left hand corner. Photo: HJB
Blueberry maggot幼虫在蓝莓中。请注意,幼虫正在运动中,并不总是以C形卷曲。照片:Shawn Banks,,,,Johnston County Cooperative Extension.
您也可以捕获成人蓝莓岩浆和SWD。如果您在果实成熟之前陷入困境,那么捕捉成年人可能会向您提供警告,警告这些昆虫在您发现水果中的幼虫之前存在。我提供了DIY说明蓝莓马戈特andSWD去年夏天陷入困境。


更多信息
自己动手 - 斑点的翅果蝇监测
Do it yourself - Blueberry maggot monitoring
保护我们 -YouTube Channel
Oregon State University Spotted Wing Drosophila Site
Michigan State University Spotted Wing Drosophila Site

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