I've been getting reports from gardeners throughout eastern Ontario that lily beetle numbers appear to be down this year compared to last year. In Ottawa, many gardens that were hit hard in previous years have had very few adults this year. It would be nice to be able to say that this was a result of successful biological control, but there simply hasn't been enough time for the wasp Tetrastichus setifer to have spread throughout the region since its release in 2010. Here's my hypothesis: the severe drought we had last summer affected larval or pupal survival. I've noticed that the larvae have a hard time forming a cocoon out of soil particles when the soil is too dry.
Reports of low numbers in Massachusetts (and possibly Connecticut?) are likely due to the spread of the biocontrol agents from the release sites.
Reports from Manitoba and from the Maritime Provinces indicate that lily beetle populations are going strong in those areas.
Write and let us know whether your beetle infestation seems more or less severe this year compared with previous years!
Reports of low numbers in Massachusetts (and possibly Connecticut?) are likely due to the spread of the biocontrol agents from the release sites.
Reports from Manitoba and from the Maritime Provinces indicate that lily beetle populations are going strong in those areas.
Write and let us know whether your beetle infestation seems more or less severe this year compared with previous years!
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