Leaftier and Leaf Roller Caterpillars

by Andrea Laine, EMGV

I recently learned about leaftiers and leaf rollers. These plant pests may be confused with one another as at first glance the damage they do to leaves looks similar.

This was a scene on my Hydrangea paniculata ‘Limelight’ in early May (see photo below). A tiny creature was cocooned on the leaves where a flower would hopefully form later this summer. Surrounding the creature the leaves were crinkly and curled in a deformed way as were leaves at the tips of other flower stems. I instinctively snipped the stem tip to minimize damage to the plant and get a closer look.

Photo by Andrea Laine

I had a hunch that the creature was the pupa of an insect. But what insect and how much damage could it potentially wreak to my, otherwise healthy, hydrangea? I was curious enough to research further; and it was a good time to re-educate myself about insect lifecycle.

Insects look different in each stage of their development. Typically, there are four stages: egg, larva, pupa, adult. The process by which insects move from stage to stage is called metamorphosis.  Most of us know that the butterflies (adult stage) we admire in our garden were once caterpillars (larva stage). We are probably less familiar with recognizing insect eggs and pupa. I know I am.

“My” pupa is likely a developing moth (insect order Lepidoptera). I believe this because of the way in which it wrapped itself in the leaves at the branch tip of the hydrangea. For protection while they morph from pupa into adults, moth larvae, i.e. moth caterpillars, spin cocoons or silky webs (behavior indicative of leaftier caterpillars), while others roll a leaf around their bodies (leaf rollers). The caterpillar feeds on the developing flower bud and leaf surfaces within their reach. The damage may be unattractive and limit bloom, but it will not kill the host plant.

Hydrangea leaftier caterpillar (Olethreutes ferriferana ) has a distinctive appearance: long green body and brown head. There are as many types of leaftiers and leafrollers as there are plants to pester. Photo credit: University of Illinois Extension.

By the time I took note of the distorted leaves on my hydrangea the moth had advanced to the pupa stage and ceased feeding. According to Durham County Agriculture Agent Ashley Troth, leaftier caterpillars drop to the ground to pupate and leaf rollers largely pupate where they have been eating. No activity on the outside belies much activity internally. During pupation many tissues and structures are completely broken down and structures of the adult are formed.2 The following spring the adult moth will emerge.

Since becoming an Extension Master Gardener Volunteer in 2015, I have become hesitant to destroy an insect lest it be one of the beneficial ones. (Prior to my EMGV education I didn’t acknowledge that many are beneficial.) Given that there are 11,000 species of moth3 in the U.S., I may never learn to distinguish between a good one and a bad one. But, so long as the nibbling of their larvae stays within reason and lets my plant produce most of its blooms, perhaps we can co-exist.

Leaftiers and leafrollers are found on a wide range of plants, including many fruit trees. Prune out the effected foliage, webbing and remove caterpillars from plants. Bacillus thuringiensis (BT) is an effective control for recurring problems, particularly if applied as soon as larvae hatch.4  Trees infested with leafrollers can furthermore be sprayed with horticultural oil.5

Footnotes,  Sources & Further Reading

1, 4, 5 http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/caterpillars/caterpillars-leaf-tiers-bagworms-and-web-former.aspx

2 https://content.ces.ncsu.edu/extension-gardener-handbook/4-insects#section_heading_5108

3 https://www.si.edu/spotlight/buginfo/moths

http://hyg.ipm.illinois.edu/article.php?id=359

When you are stumped about something gone wrong in your garden, remember Durham County Cooperative Extension’s  Ask an Expert resource. Send photos and an explanation of what you are seeing to:  mastergardeners@dconc.gov.  

Special Event: Breakfast in the Garden

Are you curious about the role of Durham County Cooperative Extension Services? Join us for breakfast at Briggs Avenue Community Garden on Friday, May 31, 8:30 – 10:30 a.m. for our 2019 Report to the Community.

Enjoy a fresh garden breakfast, tour the garden, see our new greenhouse, learn about Extension’s work in Durham County, meet our new director, Donna Rewalt, and receive a small gift of appreciation for your support.

Photo by Andrea Laine

The event begins at 8:30 a.m. and a short presentation will take place at 9:20 a.m. The event is free but registration is required so we know how much food to prepare.

Register online or call 919-560-0521.

Briggs Avenue Community Garden is located at 1598 S Briggs Avenue in Durham, NC. Get Directions.

Learn With Us, week of May 19

Composting – Durham Garden Forum
Tuesday, May 217:00 – 8:30pm
420 Anderson St, Durham, NC 27708, USA
Description:Composting
Rhonda Sherman, Extension Solid Waste Specialist
Rhonda is a leading authority on vermicomposting, with
additional expertise in composting, recycling and waste
reduction. She also brings an enthusiasm to the subject
that is infectious and energizing. Join us to learn more
about composting at home.

Lectures are free for members, $10 for general public. No pre-registration necessary. Contact: durhamgardenforum@gmail.com

Pollinators – Durham Garden Center
Saturday, May 2510:00 – 11:00am
4536 Hillsborough Rd, Durham, NC 27705, USA
Description:This POLLINATORS talk will offer information, advice and suggestions about the plants and critters that benefit our flower and vegetable gardens and our yards. Also reviewed will be some of the common pests and the diseases that can be prevented by propagating proper pollinator practices. (Say THAT three times quickly.)

Free/Registration required Contact: 919-384-7526 or http://www.durhamgardencenternc.com

Sign up at the store, online or by phone
Include the seminar title and full name(s) of persons attending

Moss in Lawns

by Flora O’Brien

Don’t get me wrong. I love all things mossy. But recently, probably because of all the rain, I’ve been getting questions about how to get rid of moss in lawns. In the spirit of equanimity I will address this subject.

If you have moss taking over your lawn the problem isn’t the moss, it’s the lawn. Turf grass struggles in areas that are too wet, too shady, too compacted, too acidic, too lacking in nutrients. These are the ideal conditions for moss, though. In order to eliminate moss, you must resolve these conditions.

A moss lawn in Saluda, N.C., November 2017. Photo by Flora O’Brien.

First address the drainage issues. Limiting the amount and frequency of lawn watering would be a first step. Slowing or redirecting the flow of water by restructuring the topography might help. You could add topsoil or install terracing stones. Placement of a French drain or similar strategies will also work.

To manage excessive shade you might have to limb up or remove trees and large shrubs. Keep in mind that the roots of trees drink large amounts of water so removing them may add to your problems. You could expand the diameter of mulch under trees and around beds. You could also try planting a grass more tolerant of shade but all of them need some sun.

Dense, compacted clay soils like we have in this area will not support turf grass for long. Yearly aeration is recommended. Leave the plugs where they lie. They will decompose and add to the soil’s fertility.

Let’s talk about fertility. First take a soil sample. It may recommend the application of lime to raise the pH and suggest a fertilization regimen. When you mow the grass leave the clippings in place to feed the soil. Good cultural practices like regular mowing, fertilizing and watering will produce the healthy lawn that will resist the growth of mosses.

How about the moss that’s already there. For small patches, dig them out, including an inch or so of the base soil and plant them in another spot. Then add new soil, seed or sod. The entire lawn could be raked dislodging the moss, new soil added and the area reseeded. There are products on the market made especially for killing moss in lawns but if the underlying conditions are not corrected, the moss will return.

Now here’s the thing. If you have wet, compacted soil in the shade you are not going to have a successful lawn without major expenditures of time and money. So why not just let the moss establish itself? You will have a year round green carpet that never needs mowing, watering, fertilizing, spraying, or plugging. It is true that mosses don’t tolerate heavy foot traffic but you could add stepping-stones or pathways. Then find a small, dry area in the sun and plant a pocket of lawn there.

NC State Fair garden vignette, October 2013, Photo by Flora O’Brien.

Sources & Further Reading

https://njaes.rutgers.edu/FS426/

https://web.extension.illinois.edu/cfiv/homeowners/030329.html

https://sampson.ces.ncsu.edu/2012/07/why-does-moss-grow-in-areas-of-my-lawn-and-not-my-grass-2/

This article originally appeared in the EMGV newsletter.

Learn With Us, week of May 12

Herbs – For Garden’s Sake Nursery
Saturday, May 1810:00 – 11:00am
9197 NC-751, Durham
Description: This talk will cover common and interesting herbs that can be grown in our area. Successful herb gardening utilizing both indoor and outdoor techniques will be addressed as well as treatment of pests and diseases that may be encountered. Also mentioned will be harvesting, preservation and perhaps an interesting recipe use or two.

Free/Registration required. To register, email ann@fgsnursery.com or call 919-484-9759