The terms “leaffolder,” “leafroller,” and “leaftier” refer to the leaf structures produced by certain moth caterpillars. Leaffolders fold leaves, leafrollers roll leaves, and leaftiers tie leaves together. The descriptive terms have no relationship to moth taxonomy. They are intended to aid in identification by portraying the caterpillar’s creative use of silk to fashion a home.
Unfortunately, moths don’t read what we write about them. Some caterpillars may produce more than one type of leaf structure creating a challenge with an accurate common name. An example is the Redbud Leaffolder (Fascista cercerisella, family Gelechiidae) which folds as well as ties the leaves of its namesake host together.
A further challenge is presented by the inaccurate use of the leaf-structure terms by different online resources. When I used the search term “leaffolder,” Google’s A.I. returned, “Leaf folders are moths and their caterpillars that [sic] roll leaves into tubes to feed inside and create shelters.”
The response by Google’s A.I. (Astounding Ignorance?) clearly missed the mark. I consider the Oak Leafroller (Archips semiferana, family Tortricidae) and the Grape Leafroller (Desmia funeralis, family Crambidae) to be the poster children for leafrollers. Both tightly roll their host’s leaves to create cigar-like structures.
Sweetgum Leafier (Leafroller)
The so-called Sweetgum Leafroller (Sciota uvinella (previously Nephopterix uvinella), family Pyralidae) occurs on its namesake host, Liquidambar styraciflua. It may be found on the straight species as well as selections such as ‘Rotundiloba’ and ‘Slender Silhouette.”
The moth species has no common name approved by the Entomological Society of America (ESA). iNaturalist uses the common name “leafroller” for this caterpillar; however, I’ve never seen them roll leaves. They may occasionally use silk to loosely tie the tips of a leaf together, but the structure is never so tight that it would be accurately described as “rolling” the leaf as illustrated by the leafrollers above.
Indeed, the authors of a scientific paper published in 1976 (see Selected References below) noted that the caterpillars tie together overlapping leaves. They did not report that caterpillars roll leaves.
Early instar caterpillars are light green with stripes that darken as they age. Later instar caterpillars are brown with dark brown stripes.
The caterpillars live within silk tubes bounded by frass (insect excrement) and constructed between the tied-leaf surfaces. The caterpillars extend their bodies a short distance out of their tubes to feed as skeletonizers. When disturbed, they quickly retreat back into their tubes. Pulling apart the tied-leaf structures will fail to expose the caterpillars unless they’re coaxed forth using a finger.
The iNaturalist map for the leafroller/tier shows observations throughout the eastern half of the U.S. from Maine to Florida. I’ve found it this season in Wooster, OH., and in northern Kentucky.
The 1976 paper notes the moth has three generations in North Carolina and overwinters as pupae in the soil. Although each new generation produces more damage, I’ve never observed enough collective damage to warrant a concern. Indeed, I consider the caterpillars to be more of an oddity rather than a significant threat to the overall health of their sweetgum hosts.
Redbud Leaffolder (Leaftier)
Participants in the OGIA/OSU Greater Cincinnati BYGL! Diagnostic Walkabout held this past Monday at the Boone County Arboretum observed the unusual damage caused by the Redbud Leaffolder on its namesake host (Cercis canadensis). Populations of this native moth appear to be sporadic and highly localized in Ohio this season. However, where populations are high, damage can be very noticeable.
The caterpillars use silk to stitch together leaf edges to produce nests that conform to the "leaffolder" common name that's approved by the Entomological Society of America (ESA). However, some nonconformist caterpillars make nests like a "leaftier" by stitching together neighboring leaves. In fact, I typically find a far greater number of leaves that have been tied together rather than folded.
Pulling apart the folded or tied leaves will expose silk stitching. Caterpillars live between the leaf layers where they feed beneath strands of heavy silk. Late instars commonly live in silk tubes festooned with frass pellets. As with the sweetgum leaffolder/leaftier, the caterpillars emerge out of their protective tubes to feed.
The caterpillars feed as skeletonizers, consuming the upper and lower leaf surfaces. The affected areas turn orangish-brown which sharply contrasts with the normal dark green color of the foliage.
Early instar caterpillars are cream-colored and have no discernible markings. As the caterpillars mature, markings begin to develop with alternating segments darkening to produce a striking appearance of black and light-green bands running the length of the body. Late instar caterpillars resemble a tiny, banded sea krait snake.
When disturbed, caterpillars in all instar stages will wiggle back and forth violently further enhancing their tiny snake impersonation. They have great entertainment value!
There has been little research attention given to the developmental biology of the leaffolder. Various online references report that there are two to three generations per year. I believe there are at least two and perhaps three overlapping generations each season in Ohio. It’s common to find both early and late instar caterpillars in the same nest as the season progresses making it difficult to separate the generations.
The velvety black female leaffolder moths tend to lay their eggs on or near the leaves from which they developed. So, the nests expand with each new crop of caterpillars. Consequently, the most significant damage occurs late in the season.
Redbud leaffolder nests are common on wild eastern redbuds. However, infestations on established trees are mainly an oddity and tend to be light and irregularly distributed throughout the canopy. The caterpillars seldom represent a threat to the overall health of the trees. On the other hand, heavy damage to wild redbud seedlings may potentially cause significant injury.
Potentially damaging populations may also occur on weeping redbuds. It’s an open question whether high populations on weeping redbuds are related to a host preference based on food value, or if it’s a physical preference. The vertical orientation of the leaves causes them to naturally overlap which may make it easier for the caterpillars to tie multiple leaves together. Of course, the cascading leaves certainly make the leaffolder damage more obvious.
I could only find one study that mentions possible host preferences among redbuds. The study was conducted in the U.S. National Arboretum and published in 2007. The authors observed that Chinese redbuds (C. chinensis) with semi-rugose leaves were resistant to the redbud leaffolder. However, no host evaluation data was presented, and no observations were reported on native redbuds.
Redbud leaffolder damage to landscape trees seldom affects the tree’s overall health; however, it can seriously reduce the tree’s aesthetic appeal, particularly on weeping redbuds. Where practical, populations can be reduced by pinching nests to kill caterpillars.
The moth spends the winter as pupae in debris and fallen leaves beneath infested trees. So, raking and destroying fallen leaves will help to reduce localized numbers by taking the overwintering pupae that remain attached to fallen leaves out of the picture.
Although the redbud folder isn’t considered a tree health-threatening pest in forests or landscapes, heavy leaffolder activity on nursery stock can affect marketability. I’ve included two publications in “Selected References” below that provide insecticide efficacy information.
Persimmon Leaffolder / Sculptured Moth
During a team trip to the Cincinnati region a few weeks ago, members of the OSU Buckeye Environmental Horticulture Team (BEHT) observed leaffolding structures produced by caterpillars of the Sculptured Moth (Eumarozia malachitana, family Tortricidae) on native persimmon (Diospyros virginiana). The caterpillars have no common name; however, I’m calling them the persimmon leaffolder.
Although the “sculptured moth” common name for the species isn’t approved by the ESA, the name is used in iNaturalist and other resources. It’s descriptive of the beautiful little moths.
The specific epithet, malachitana, is also descriptive. The name refers to the deep green late-instar caterpillars and is derived from the gemstone, malachite.
I’m using “leaffolder” in the common name because this nest behavior appears to dominate. However, the caterpillars will also tie leaves together.
The species is reported in various taxonomic and biodiversity checklists from Maine to Florida and west to Michigan, Missouri, and Arkansas. However, I found no information on the biology, impact, or management of the caterpillars.
Based on personal observations, it’s possible the caterpillars are seldom observed causing significant, or perhaps even noticeable, damage to their hosts. In fact, this is the first season that I’ve observed this moth caterpillar; it may only be an oddity.
The Natural History Museum’s Host Database [ https://data.nhm.ac.uk/dataset/hosts ] lists the following genera and species as hosts for this caterpillar: Cassia, D. virginiana, D. digyna, Gomphrena, Manilkara, Ostrya virginiana, and Pyrus communis.
Selected References
Doerksen, G.P. and Neunzig, H.H., 1976. Biology of some immature Nephopterix in the eastern United States (Lepidoptera: Pyralidae: Phycitinae). Annals of the Entomological Society of America, 69(3), pp.423-431. Available at: https://academic.oup.com/aesa/article/69/3/423/31373
Rebek, E.J., 2011. Evaluation of Foliar Applications of Acelepryn (Chlorantraniliprole) and DPX-HGW86 (Cyantraniliprole) for Redbud Leaffolder Control, 2009. Arthropod Management Tests, 36(1). p. G8
https://go.osu.edu/redbudleaffolder1
Rebek, E.J., 2011. Evaluation of Soil Applications of Acelepryn (Chlorantraniliprole) and DPX-HGW86 (Cyantraniliprole) for Redbud Leaffolder Control, 2010. Arthropod Management Tests, 36(1), p.G9.
https://go.osu.edu/redbudleaffolder2
