Hot on the trail of caterpillar frass

My cannas have rarely looked lovelier. The leafrollers never showed up to roll the leaves with their sticky white goo and eat holes through the "cigars" this summer.

Just as I was celebrating, my creeping myrtle aka periwinkle aka vinca minor leaves became folded, brown, and brittle. This never happened before. The leaves reminded me of the powdery mildew on flowering crape myrtles (completely unrelated to creeping myrtle). That put me off the trail briefly, though I really suspected an obnoxious, poopy insect.

My little students are fascinated with the tomato hornworms that hide in our school garden. Hornworms are frass champions, meaning they can outpoop any other insect and many small mammal pets on any given day. My patio pests aren't hornworms.

What kind of insect goes to the trouble of neatly folding and gluing itself inside a leaf just to suck out all the green food goodness and leave frass in the living room before vacating the premises for the next leaf on the vine? Okay, it does remind me of some rugby players I knew in college who would throw major parties to get evicted instead of paying their rent. This insect is not large enough to carry the beer kegs into the rental house, though.

Yesterday I attacked the ugly plants to work out unsuccessful water heater service frustrations. Hacked the vinca way back, and bagged it, along with other overgrown plants in a sweaty machete mama therapy. I left enough periwinkle for it to revive, but not much for pest food. I only spotted one likely villain. The little yellow and green caterpillar with black spots, an orange head, and a Groucho Marx leer disappeared too quickly.

Today I wanted to catch Groucho in the act. I followed a series of frass-filled brittle ruins of former leaf room-&-boards to a still-green and moist folded leaf flophouse. Yes! This dude has played his last rugby game! No more free rent. No more beer and Cheetos. He's spending the rest of his days in a periwinkle-filled Ragu jar with tiny holes in the lid. I may have to play good cop/bad cop to learn why Groucho went for the vinca this year, instead of the cannas.

What do you do about leaf-rollers on Cannas, Vinca Minor and Vinca Major? Parker County Master Gardener La Donna Stockstill

...Damaged canna blades become notched and ragged. When they mature and open, they look like someone has shot them with a B B gun. One finds robust caterpillars hidden inside leaf rolls. Canna leaf-roller caterpillars are clear white at first. They become semi-pale green with age. Lesser canna leaf-roller caterpillars are smaller and yellow. Large ornate butterflies lay eggs from which they hatch. The caterpillars spin silk thread used to pull leaf edges together. They hide inside the protective tube, presumably to avoid predators. Leaf rollers in late summer are devastating to foliage of vinca major and to some lesser degree to vinca minor and should be prevented with systemic insecticide before they begin... If the damage has been done, you will may want to cut the marred foliage back and allow new growth to cover the area ...

You may want to check references before renting to rugby players, too.

© 2007 Nancy L. Ruder

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