Project GREEEN committed to controlling spotted wing drosophila
Project GREEEN has invested significant resources into mitigating the effects of the invasive pest spotted wing drosophila.
Spotted wing drosophila is an invasive fly that was first detected in the U.S. in California in 2008. SWD has now been reported in 34 states, including detection in Michigan in 2010. SWD is able to attack undamaged, ripening fruit using a specialized ovipositor to pierce the skin of the fruit and deposit eggs.
This pest has a wide host range, with berry crops and cherries most susceptible to infestation. In the first two years following its detection in the U.S., SWD was responsible for annual losses of $500 million in a wide range of crops, including 30 to 40 percent of California cherries. In Michigan, SWD may have up to 13 generations per growing season. The short generation time, coupled with a high reproductive potential, results in rapid population growth.
Project GREEEN has devoted many resources toward understanding SWD behavior and developing control mechanisms. Just this past year, Project GREEEN is supporting these efforts:
Biology and detection of the overwintering stage of SWD
SWD overwinters as an adult fly. As temperatures and hours of daylight decrease, developing larvae change into what has been described as a winter morph phenotype. Researchers are determining the survival rate of winter morph SWD under Michigan field conditions and the overwintering locations. Wilson said they also seek to understand if the winter morphs behave similarly in terms of which colors and stimuli attract them. This can help to optimize the winter and spring monitoring programs to detect SWD earlier. The team is continuing winter field trapping experiments with the intention of delivering outreach presentations, writing articles and reports, and preparing web-based materials for growers.
Development of post-harvest cultural management tactics for SWD
Researchers are trying to determine the potential of fruit compost mixes as potential SWD breeding resources. They are also evaluating cultivation as well as larval and pupal burial as a potential late season SWD management tactic. Sharing project findings via MSU Extension activities and developing leveraged proposals is the next step.
Identifying efficient and selective attractants for SWD using its natural yeast symbionts
Larry Gut, a professor of entomology, said that researchers are determining the behavioral preferences of SWD, comparing its symbiotic yeast and baker’s yeast in the laboratory and in the field. Researchers are looking at whether the attractiveness of symbiotic yeast is affected by crop types: blueberry, blackberry and cherry. The team is seeking to develop an attractive dry lure using odors released from preferred yeast strains and determine its attractiveness and specificity in the laboratory and in the field.
Diversifying tactics for managing SWD in Michigan blueberries
SWD pressure has driven up production costs and increased insecticide use, an unsustainable situation economically and environmentally. Entomology professor Rufus Isaacs is exploring alternative approaches for making management of this pest more diversified and sustainable. These tactics include adjusted pruning practices and mulching options to make fields less suitable for SWD, testing different insecticides and monitoring current biological control levels. Information from this project will be integrated into an existing online, printed and in-person MSU Extension program for SWD management.
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