BYGL Bug Bytes July 3, 2008 SOME BLUEBERRY BLUES
| SOME BLUEBERRY BLUES |
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 Tim Malinich and Erik Draper reported a few blueberry growers are singing the blues over two blueberry insects, namely, the CRANBERRY FRUITWORM (Acrobasis vaccinii) and the BLUEBERRY MAGGOT (Rhagoletis mendax). Both of these insects cause damage to blueberry fruit, but in noticeably different ways. These differences will help identify the true culprit responsible for putting the blues into blueberry picking. Control of these pests is achieved by timing applications of insecticides to prevent the larvae from entering the fruit.
The cranberry fruitworm is a serious pest of blueberries in the Eastern United States. More often than not, the early ripening blueberry varieties are typically most affected. This insect overwinters in the soil as a full grown larva. The larvae pupate in the spring and the adult moths begin to emerge after blueberries bloom and set fruit. The adults are small moths with dark grayish-brown wings, and they fly at night. The female deposits eggs on the berries, almost always on or inside the calyx cup (blossom end) of unripe fruit. The eggs hatch in about five days and the young larvae travel to the stem end of the fruit where they enter, and feed on the berry flesh. The larva moves within a fruit cluster, traveling from one berry to another. One larva may feed on up to eight berries before it completes its development. The fruitworm larva feeds entirely on the inner flesh of developing and ripening berries. These damaged berries are usually webbed together, covered with brown sawdust-like excrement (frass), and the tunnels in the berries are also filled with frass where the cranberry fruitworm ate its way through. There is one generation per year. The blueberry maggot, which is an immature fly, overwinters as a pupa in the soil. Adults emerge over a period of time from about mid-June through mid-August. Female flies begin laying eggs about 10 days after their emergence. The female will lay only one egg per berry, under the skin, just as the fruit begins to turn blue and ripen. The egg hatches in about one week and the maggot feeds for about three weeks inside the ripening fruit. As the maggot tunnels throughout the berry, the fruit flesh liquefies as it matures. Infested fruits are soft, sometimes shriveled and may have a depression or hole where the egg was inserted. Small larvae are colorless making their detection almost impossible. Full-grown larvae are about 1/4" - 5/16" long, glossy white or yellowish in color, legless, with bodies tapering towards the head end. There is one generation per year. Fruitworms and maggots provide a cautionary message: If the pie moves … Don't eat it! For more information, see:
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| Last Updated ( Friday, 04 July 2008 11:28 ) |
