Pests & Diseases
Tuesday, September 1st, 2009
The saddleback caterpillar is stunningly beautiful, but it is most likely to impress its presence upon you with a devilish sting. If you innocently brush against one where it hangs on the underside of a leaf, you will be punished with an intensely burning welt for several minutes at least. Perhaps you can forgive its cruelty as you marvel at its vivid color and otherworldly form.
The caterpillar’s common name refers to the brown, saddle-like blotch in the center of its rich kelly green back. Each end is capped with reddish-brown and bears a pair of imposing bristly “horns.” The head…
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Monday, August 24th, 2009
Dogwood sawfly, Macremphytus tarsatus, has been found on shrubby dogwood species on campus. While this pest looks like a caterpillar, it is actually the larval stage of a wasp-like Hymenoptera species.
Adult sawflies emerge in late spring and lay their eggs on the undersides of leaves. When the eggs hatch in mid-summer, the first stage larvae are tiny, yellow, and translucent. As they grow and molt, they become covered with a white waxy coating. They usually spend the daylight hours curled up and clinging to the underside of leaves. They can be quite gregarious, with a dozen or more congregating on one…
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Monday, July 27th, 2009
We are excited about weevils at the Scott Arboretum. The stem-boring weevil, Rhinoncomimus latipes, has been found throughout the Arboretum nibbling on the invasive mile-a-minute weed, Polygonum perfoliatum.
Mile-a-minute weed is an annual Asian vine that has invaded habitats in the northeastern US: forested floodplains, streamside herbaceous wetlands, and upland forests. It can be found growing along the Crum Creek, in the Crum Woods, and on banks throughout the campus.
This prickly, branching vine germinates in April in the Mid-Atlantic region and proceeds to rapidly climb over other plants. It produces iridescent blue berry-like achenes in the beginning of mid-summer, completing its…
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